Directives - Table of Contents Directives - Table of Contents
• Record Type: Instruction
• Old Directive Number: CPL 03-00-007
• Title: National Emphasis Program – Crystalline Silica
• Information Date: 01/24/2008


OSHA INSTRUCTION

DIRECTIVE NUMBER: CPL 03-00-007 EFFECTIVE DATE: 1/24/08
SUBJECT: National Emphasis Program - Crystalline Silica


ABSTRACT


Purpose: This instruction describes policies and procedures for implementing a National Emphasis Program to identify and reduce or eliminate the health hazards associated with occupational exposure to crystalline silica.
 
Scope: This instruction applies OSHA-wide.
 
References: OSHA Instruction CPL 02-00-103 (CPL 2.103), September 26, 1994, Field Inspection Reference Manual (FIRM).

OSHA Instruction CPL 02-00-140, June 26, 2006, Complaint Policies and Procedures.

OSHA Instruction CPL 02-00-025 (CPL 2.25I), January 4, 1995, Scheduling  System for Programmed Inspections.

OSHA Instruction CPL 02-00-051(CPL 2-0.51J), May 28, 1998, Enforcement Exemption and Limitations under the Appropriations Act.

OSHA Notice CPL 07-03 (CPL 02), May 14, 2007, Site-Specific Targeting 2007 (SST-07).

OSHA Instruction CPL 02-00-120 (CPL 2-0.120), September 25, 1998, Inspection Procedures  for the Respiratory Protection  Standard.

OSHA Instruction CPL 02-02-038 (CPL 2-2.38D), March 20, 1998, Inspection Procedures  for the Hazard Communication  Standard.
 
Cancellations: OSHA Instruction CPL 02-02-007 (CPL 2-2.7), Crystalline Silica, October 30, 1972.

OSHA Instruction CPL 02-02-007 (CPL 2-2.7 CH-1), Removal of Obsolete Sections, June 3, 1985.

Memorandum for Regional Administrators from Joseph A. Dear, Assistant Secretary, May 2, 1996, Subject: Special Emphasis Program (SEP) for Silicosis.
 
State Impact: This Instruction describes a Federal Program change  for which state adoption is not required (See Paragraph V).
[State Adoption Summary]
 
Action Offices: OSHA Regional and Area Offices, State Plan and State Consultation Offices
 
Originating Office: Office of Health Enforcement Programs
 
Contact: Directorate of Enforcement Programs
Office of Health Enforcement Programs
200 Constitution Avenue, NW, N3603
Washington, DC 20210

By and Under the Authority of

Edwin G. Foulke, Jr.
Assistant Secretary




Executive Summary

In 1996, the Occupational Safety and Health Administration (OSHA) issued a memorandum establishing a Special Emphasis Program (SEP) for Silicosis, which provided guidance for targeting inspections of worksites with employees at risk of developing silicosis . This instruction establishes a National Emphasis Program (NEP) that expands and builds upon the 1996 SEP. This instruction addresses targeting of worksites with elevated exposure to crystalline silica, as well as silica-related inspection procedures and compliance assistance.  All Local Emphasis Programs (LEPs) for silica-related activities may remain in effect under this NEP.  Any conflicts between an LEP and an NEP should be resolved in favor of the NEP.

Significant Changes

This Instruction expands the 1996 SEP to include the following changes:
  • New program evaluation  procedures designed to ensure that the goals of this NEP are measured as accurately as possible. The procedures require Area Offices to conduct follow-up inspections where overexposures to crystalline silica are found and to provide to the National Office-Directorate of Enforcement Programs portions of case files containing citations for crystalline silica overexposure;

  • Detailed procedures for conducting silica-related inspections;

  • Updated information for selecting sites for inspection, including an updated list of North American Industrial Classification System (NAICS) and Standard Industrial Classification (SIC) codes for industries with documented employee exposures to respirable crystalline silica (as described in Appendix B);

  • Development of outreach  programs by each Region and Area Office, emphasizing the formation of voluntary partnerships  to share information on effective methods for reducing or eliminating employee exposure to crystalline silica; and

  • Guidance on calculating the permissible exposure limits (PELs) for dust containing respirable crystalline silica in Construction and Maritime, using the OSHA-adopted conversion factor of 0.1 milligrams per cubic meter (mg/m³) per 1 million particles per cubic foot (mppcf), described in Appendix E.


Table of Contents

  1. Purpose
  2. Scope
  3. References
  4. Cancellation
  5. Federal Program Change
  6. Consultation Programs
  7. Action
  8. Application
  9. Background
  10. National Emphasis Program Goals
  11. Program Procedures Appendix A: Background Information on Silica
    Appendix B: Industries with Potential Overexposure to Crystalline Silica
    Appendix C: Guidelines for Air Sampling
    Appendix D: Cyclone Leak Test Procedure
    Appendix E: Conversion Factor for Silica PELs in Construction and Maritime
    Appendix F: Employee Questionnaire
    Appendix G: Non-Mandatory Medical Monitoring Recommendations for Employees Exposed to Crystalline Silica
    Appendix H: CSHO Checklist for Conducting Silica-Related Inspections
    Appendix I: Case File Components to be Sent to the National Office
    Appendix J: Bibliography
    INDEX





  1. Purpose.

    This instruction describes policies and procedures for implementing a National Emphasis Program (NEP)  to identify and reduce or eliminate the health hazards associated with occupational exposure to crystalline silica.

  2. Scope.

    This instruction applies OSHA-wide.

  3. References.

    1. OSHA Instruction CPL 02-00-103 (CPL 2.103), September 26, 1994, Field Inspection Reference Manual (FIRM).

    2. OSHA Notice CPL 07-03 (CPL 02), May 14, 2007, Site-Specific Targeting 2007 (SST-07).

    3. OSHA Instruction CPL 02-00-140, June 26, 2006, Complaint Policies and Procedures.

    4. OSHA Instruction CPL 02-00-025 (CPL 2.25I), January 4, 1995, Scheduling  System for Programmed Inspections.

    5. OSHA Instruction CPL 02-00-051 (CPL 2-0.51J), May 28, 1998, Enforcement Exemptions and Limitations under the Appropriations Act.

    6. OSHA Instruction TED 01-00-015 (TED 1-0.15A), January 20, 1999, Occupational Safety and Health Administration Technical Manual.

    7. Memorandum for Regional Administrators from R. Davis Layne, Deputy Assistant Secretary, July 12, 1999, Subject: Strategic Plan IMIS Coding.

    8. OSHA Instruction CPL 02-00-120 (CPL 2-0.120), September 25, 1998, Inspection Procedures  for the Respiratory Protection  Standard.

    9. OSHA Instruction CPL 02-02-038 (CPL 2-2.38D), March 20, 1998, Inspection Procedures  for the Hazard Communication  Standard.

    10. OSHA Instruction CPL 02-00-135, Recordkeeping  Policies and Procedures Manual (RKM), December 30, 2004.

  4. Cancellation.

    1. OSHA Instruction CPL 02-02-007 (CPL 2-2.7) Crystalline Silica, October 30, 1972.

    2. OSHA Instruction CPL 02-02-007 (CPL 2-2.7 CH-1), Removal of Obsolete Sections, June 3, 1985.

    3. Memorandum for Regional Administrators from Joseph A. Dear, Assistant Secretary, May 2, 1996, Subject: Special Emphasis Program (SEP) for Silicosis.

  5. Federal Program Change.

    This instruction describes a Federal program change which establishes a National Emphasis Program (NEP) to reduce or eliminate employee exposure to crystalline silica through inspection targeting, outreach and compliance assistance.  States with a similar strategic goal regarding crystalline silica or with significant exposures are encouraged to participate in this national emphasis effort.  State notice of intent regarding this directive is required.

    The State's notice of intent must indicate whether it will initiate an emphasis program and if so, whether the State's program will be identical to or different from the Federal.  The States' implementing policies and procedures are expected to be at least as effective as those in this instruction and must be available for review.  If the State's program differs from the Federal, the State may either post its different emphasis program on its State plan website and provide the link to OSHA or provide information on how a copy may be obtained.  OSHA will provide summary information on the State responses to this instruction on its website.

    The assignment of appropriate IMIS identifier codes for State Emphasis Programs should be coordinated with the Directorate of Information Technology and the Regional Administrator.

  6. Consultation Programs.

    When appropriate, Consultation Projects are encouraged to develop their own strategic approaches for addressing overexposures to silica, as well as to reduce the health hazards associated with occupational exposure to crystalline silica .

  7. Action.

    1. Responsible Office.

      Office of Health Enforcement, Directorate of Enforcement Programs.

    2. Action Offices.

      OSHA Regional and Area Offices, State Plan and State Consultation Offices.

    3. Information Offices.

      OSHA National Office.

  8. Application.

    This instruction applies to general industry and construction workplaces where crystalline silica is present.

  9. Background.

    1. The term "silica" refers broadly to the mineral compound silicon dioxide (SiO2). Silica can be crystalline or amorphous.  Crystalline silica is significantly more hazardous to employees than amorphous silica.  In addition to causing the disabling and irreversible lung disease silicosis , crystalline silica has been classified as a Group I carcinogen - Carcinogenic to Humans by the International Agency for Research on Cancer (IARC ) [IARC, 1997].  The term "silica" as it is used in this directive refers specifically to crystalline silica.

      Crystalline silica is an important industrial material, and occupational exposure occurs in a variety of workplace settings, including mining, manufacturing, construction, maritime, and agriculture.  Processes associated historically with high rates of silicosis  include sandblasting, sand-casting foundry operations, mining, tunneling, cement cutting and demolition, masonry work, and granite cutting.  Appendix A provides further information on silica, including sources, industrial uses, and adverse health effects.  Appendix B provides a list of North American Industrial Classification System (NAICS) and Standard Industrial Classification (SIC) codes for industries in which silica exposure occurs frequently, based on a review of OSHA inspection data for the period 1996 to 2007.

    2. Reducing and ultimately eliminating the workplace incidence of silicosis  has been a primary goal of the Agency since its inception.  In 1972, OSHA issued guidelines for conducting inspections in workplaces with significant crystalline silica exposure.  In the early 1980s, the Agency placed a special emphasis on the prevention of silicosis in foundry personnel, and in 1996 OSHA implemented a Special Emphasis Program (SEP) to reduce the workplace incidence of silicosis.

      The 1994 Government Performance and Results Act (GPRA ) mandates that federal agencies improve performance and devise a system for measuring results. To comply with the provisions of GPRA, OSHA developed a Strategic Plan for improving the safety and health of all employees.  In 1998 and again in 2003, under the Strategic Plan, OSHA identified crystalline silica as one of the focused hazards.

      This NEP is being implemented to direct OSHA's field staff inspection efforts to address elevated silica exposures in the workplace, including General Industry (1910) and Construction (1926). These efforts meet the Strategic Plan goal of reducing silicosis , set forth by the Agency.

  10. National Emphasis Program Goals.

    The purpose of this NEP is to significantly reduce/eliminate employee overexposures to crystalline silica and, therefore, control the health hazards associated with such exposures.  This goal will be accomplished by a combined effort of inspection targeting, outreach  to employers, and compliance assistance.

    Inspections should be targeted to work sites that likely create high silica exposures. In each Region, at least 2 percent of inspections every year must be silica-related inspections.  Additionally, the silica-related inspections should be conducted at a range of facilities reasonably representing the distribution of general industry and construction work sites in that region.

    To ensure abatement and measure the effectiveness of this NEP, follow-up site visits often will be necessary as outlined in Section XI.(D.) below.

  11. Program Procedures.

    1. LEP Development.

      Inspections conducted under this NEP will focus on industries where employees are potentially exposed to levels of crystalline silica in excess of the permissible exposure limit (PEL).  Appendix B, which was developed from OSHA inspection data, lists industries with potential silica exposure and provides an overview of the types of industries in which silica exposures frequently occur.  Each Area Office (AO) or Regional Office (RO) that does not already have a Local Emphasis Program (LEP) for crystalline silica, will develop and implement a LEP for crystalline silica based on one or more of the industries in Appendix B.

      1. Industry Selection

        Each Area Office (AO) or Regional Office (RO) will identify the industry sectors that are to be targeted by the AO or RO and shall then prepare a master list of NAICS codes from those listed in Appendix B.  The rationale for selecting each industry shall be documented, and may include information such as, but not limited to:

        1. History of overexposures, based on previous local inspection history within a RO or AO's jurisdiction of industries listed in Appendix B.

        2. Limited or no local inspection history of an industry listed in Appendix B.

        3. The AO or RO may establish knowledge of a pattern of silicosis or overexposures to silica by reviewing objective illness or exposure data from any and all sources including, state workers' compensation records or public health data from sources such as the National Institute for Occupational Safety and Health (NIOSH).

        4. Industries that are not included in Appendix B, but are known by the AO or RO, based on local knowledge (i.e. a documented history of referrals from local agencies or healthcare providers, or previous inspection histories, etc.), to have demonstrated a pattern of silica overexposures or cases of silicosis.

      2. Site Selection

        1. Targeting Sources

          After selecting the industries each RO, or AO in coordination with the RO (instead of the NO), shall develop a master list of establishments to be inspected in accordance with OSHA Instruction CPL 02-00-025 (CPL 2.25I)-Scheduling Systems for Programmed Inspections.

        2. Master List Generation

          After identifying the relevant industries, each Regional or Area Office, using all available information, will prepare a master list of establishments within the designated industries.  Establishments with fewer than 10 employees shall also be included in this NEP.  Establishments will be placed on the list in alphabetical order, and appropriate deletions shall be made in accordance with OSHA Instruction CPL 02-00-025 (CPL 2.25I), Scheduling System for Programmed Inspections, at B.1.b.(1)(b)(6).  Establishment sources may include:

          1. the Dun & Bradstreet employer list (available from the National Office);

          2. commercial directories;

          3. telephone listings;

          4. local knowledge of establishments;

          5. Dodge reports for construction sites.

        3. Deletions

          Based on their familiarity with local industries, Regional and Area offices shall delete from the master list any firms known to be out of business.

          The Regional and Area Offices shall also delete any establishment that has had an inspection where employee exposures to silica have been evaluated within the previous three (3) years, provided either that no serious violations related to silica exposures were cited or that serious violations were cited but a follow-up inspection documented effective abatement of the cited conditions.

        4. Cycle Generation

          Each establishment on the corrected list will be assigned a sequential number, starting at the top of the list with number one.  A random number table will then be applied to create the first inspection cycle of five or more establishments.  Subsequent cycles will be created in the same way until the expiration of the LEP or until all establishments on the list have been assigned to a cycle.  Cycles may be created all at once or as needed, and need not be of the same size.

          Whenever an office becomes aware of a previously unknown establishment in one of the identified NAICSs, that establishment shall be added to the master list for inclusion in the next inspection cycle.

      3. Inspection Scheduling:

        Within a specified cycle, inspections may be scheduled in any order to make efficient use of resources.  An inspection cycle must be completed before another cycle is started except that establishments may be carried over in accordance with OSHA Instruction CPL 02-00-025 (CPL 2.25I), at B.1.b.(1)(d).

        For construction, inspections shall be scheduled from a list of construction work sites rather than construction employers, pursuant to CPL 02-00-025 (CPL 2.25I).  If during the course of any construction inspection a Compliance Safety & Health Officer (CSHO) encounters a site that falls within any of the NAICS codes listed in Appendix B, that inspection shall also focus on any activity(s) that potentially exposes employees to silica.

      4. Complaints  and Referrals:

        Detailed guidance regarding complaints and referrals is provided in OSHA Instruction CPL 02-00-140, June 26, 2006, Complaint Policies and Procedures.

      5. Site-Specific Targeting (SST-07):

        Targeted establishments which also appear on the Site-Specific Targeting (SST) list will undergo a DART/DAFWII evaluation.  The evaluation of the establishment's DART and DAFWII rates shall be made in accordance with OSHA Notice CPL 07-03 (CPL 02), May 14, 2007, Site-Specific Targeting 2007 (SST-07), or successor guidance replacing the SST-07.  If the evaluation shows that the site has DART/DAFWII rates below the SST-07 cut points, then the inspection will be conducted focused on only the hazards related to silica, otherwise the silica inspection should be done concurrently with the SST Plan.  If this is not possible, the SST plan inspections have priority and are to be conducted prior to NEP inspections.  Refer to OSHA Notice CPL 07-03 (CPL 02), May 14, 2007, Site-Specific Targeting 2007 (SST-07).

      6. Voluntary Compliance Programs

        Employers participating in voluntary compliance programs may be exempt from programmed inspections.  The CSHO should follow the procedures outlined in the FIRM, Section A.3.e., for additional guidance if an on-site consultation visit is in progress, or if the establishment is a participant in OSHA's Voluntary Protection Programs (VPP) or the Safety and Health Achievement Recognition Program (SHARP).

      7. Strategic Partnerships

        Inspections initiated at establishments currently engaged in a strategic partnership with OSHA that have been established in accordance with OSHA  Instruction CSP 03-02-002, Strategic Partnership Program for Worker Safety and Health, December 9, 2004, shall be conducted in accordance with the terms outlined in the partnership agreement.  Establishments engaged in partnerships may be exempt from programmed inspection for six (6) months, or may qualify for focused inspections, the scope of which is specified in the partnership document.

      8. Expanding Scope of Inspection:

        The Compliance Safety and Health Officer (CSHO) may expand the scope of an LEP inspection beyond the silica-related activities if other hazards or violations are observed, following the guidelines set forth in the FIRM.

      9. LEP Evaluation

        One year from implementation, each LEP will be evaluated and a determination made as to the effectiveness of the LEP using Appendix A of CPL 04-00-001 - Procedures for Approval of Local Emphasis Programs (LEPs).  If the LEP is determined to be ineffective, different industries from Appendix B will be selected and a new LEP developed and implemented.  If the LEP is determined to be effective but the master list of establishments has been depleted to the point of having too few work sites for each cycle, different industries from Appendix B will be selected and a new LEP developed and implemented.  If the LEP is determined to be effective and the master list of establishments still contains enough employers, the LEP may be renewed.

    2. Inspection Procedures.

      This section outlines procedures for conducting inspections and preparing citations for silica-related violations.  For further guidance, the CSHO should consult the OSHA directives, appendices, and other references  provided below.  Appendix H contains a checklist that summarizes the information to be documented during a silica-related inspection. The checklist may be used by the CSHO to ensure proper coverage of the essential elements of a silica-related inspection.

      1. Employee Exposure Monitoring:

        1. Conduct monitoring to determine employee exposure to respirable dust containing crystalline silica, in accordance with the OSHA Technical Manual (OTM), Section II, Chapter 1 and OSHA method ID-142.  Appendix C contains guidelines on collecting air samples and Appendix D summarizes procedures for performing leak tests on cyclones.

        2. Obtain bulk samples  of settled dust from silica operations, in accordance with the OTM, Section II, Chapters 1 and 4.

        3. Review any existing employer's silica exposure monitoring records.

          Citation Guidance:  When the PEL for respirable dust containing silica is exceeded (regardless of the use of PPE), the CSHO should cite 1910.1000(c) or 1926.55(a) for the relevant industry in accordance with the FIRM (Chapter III, Section C.1.b.).

          For construction, exposures are not based on the general industry PEL, but are determined gravimetrically and converted to mppcf and should therefore be cited as exceeding the construction PEL in mppcf.  Appendix C contains guidance on calculating the general industry PEL, and Appendix E provides information on calculating the construction and maritime industry PELs for crystalline silica.

      2. Engineering and Work Practice Controls:

        1. Document and evaluate any engineering and work practice controls in place intended to reduce exposure to respirable crystalline silica, such as:

          1. Location of employee(s) with respect to dust generation source.

          2. Isolation (e.g., control room, enclosures, or barriers).

          3. Local exhaust ventilation (LEV) systems.

          4. Wet methods for cutting, chipping, drilling, sawing, grinding, etc.

          5. Use of HEPA-equipped vacuums or wet sweeping for cleaning.

          6. Employers should be advised not to use compressed air  for cleaning silica contaminated surfaces.

          7. Substitution with non-crystalline silica material.

          8. Use of tools with dust collecting systems.

          Controls for abrasive blasting are addressed further in Section XI(B)(7), below.

        2. Guidelines for investigations of ventilation systems are contained in the OTM, Section III, Chapter 3.

          Citation Guidance: If an employer fails to implement feasible engineering or work practice controls for reducing respirable crystalline silica exposures to levels less than the PEL, the CSHO should cite 1910.1000(e), 1926.55(b), or 1926.57(a) and (b), as appropriate.  Guidance on what constitutes feasible administrative, work practice, and engineering controls is provided in the OSHA Field Inspection Reference Manual (FIRM), CPL 02-00-103 (CPL 2.103), Section 8, Chapter IV.  Information is also available on the OSHA website.

          Subsequent citations may not be appropriate when all of the following conditions have been met:

          1. the employer has fully implemented the feasible means of abatement recommended in the previous citation;

          2. the employer has fully implemented a respiratory protection program;

          3. applicable engineering controls used to address the hazard have not significantly advanced since the previous citation.

          Under these conditions, the Area Office shall contact the Regional Office for guidance.  (Note:  This policy is limited to situations where the employer has made good faith efforts to comply with the silica exposure limit by implementing engineering controls previously suggested by the Area Office but which have not reduced exposures below the PEL.  In such situations requiring the employer to continue to implement additional controls which may not reduce the exposures below the PEL may be inappropriate.)

      3. Respiratory Protection:

        1. Detailed inspection and citation guidance related to respiratory protection is contained in OSHA Instruction 02-00-120 (CPL 2-0.120) - Inspection Procedures  for the Respiratory Protection  Standard.

        2. Minimum Respiratory Protection: When respirators are a permissible means to address overexposure, the minimum respiratory protection for employees exposed to crystalline silica during operations, other than abrasive blasting, is the N95 NIOSH-approved respirator for exposures that do not exceed the assigned protection factor .

        3. Medical Evaluations for Respirator Use:  Medical evaluations must be given to all employees required to wear a respirator, however, medical evaluations are not required for employees who voluntarily use filtering face-piece respirators (dust masks). Employees who refuse to be medically evaluated cannot be assigned to work in areas where they are required to wear a respirator.

      4. Hazard Communication:

        1. Detailed inspection and citation guidance related to hazard communication is contained in OSHA Instruction CPL 02-02-038 (CPL 2-2.38D)-Inspection Procedures  for the Hazard Communication  Standard.

        2. Labeling of Carcinogens:  Information regarding evidence of carcinogenicity must be included on container labels and Material Safety Data Sheets (MSDSs) for crystalline silica, and for products containing crystalline silica.  Carcinogen warnings are required on containers of materials containing more than 0.1 percent crystalline silica by weight or volume, as determined by analysis of a bulk sample of the original product.  The CSHO should collect bulk samples  to determine silica content if MSDSs appear inadequate or incomplete.

        3. Bricks/Tiles/Cement boards:  Bricks, tiles and cement boards containing silica fall under the requirements of the Hazard Communication  standard (HCS) due to the hazards associated with silica.  Under normal conditions of use, bricks, tiles and cement boards are cut, sawed, or drilled, generating airborne levels of crystalline silica that could result in elevated exposures and are therefore not considered to be exempt under the HCS as articles.  Note: Bricks do not need to be individually labeled.  Bricks that are palletized and bound by metal bands are considered to be containers and are to be tagged with an appropriate label.

        4. Crushed Stone:  Vehicles hauling shipments of crushed stone  shall include hazard warnings concerning the carcinogenicity of crystalline silica on their shipping papers or bills of lading.  CSHOs should initially determine whether the Mine Safety and Health Administration (MSHA ) or OSHA has jurisdiction over the specific crushed stone operation.

      5. Housekeeping and Hygiene Practices:

        1. Determine whether the employer's housekeeping  and hygiene practices may contribute to overexposure.  For example:

          1. Exposed surfaces should be as free as practicable of silica-containing dust (bulk samples  of the dust may need to be collected).

          2. Contaminated surfaces should not be blown clean with compressed air or other forced air (such as leaf blowers).

          3. Wet sweeping should be used to clean areas if possible.

          4. If vacuuming is used for cleaning, the exhaust air should be properly filtered to prevent release of airborne silica back into the workroom.

          5. There should be separate break areas for consuming food, beverages, etc. that are kept free of silica.

          6. Clothes contaminated with silica should not be blown or shaken to remove dust.

        2. Document poor housekeeping  and hygiene practices.

          Citation Guidance: If employees are overexposed to crystalline silica, and poor housekeeping  practices are noted, the CSHO should cite, as applicable, 1910.141, 1926.51(f), or 1926.51(g).

      6. Employee Exposure and Medical Records:

        1. Interview employees to determine whether they understand their right to review their medical and exposure records, as well as their rights regarding the confidentiality of such records.

        2. Review the employer's recordkeeping program to ensure that the required information is being collected and reported.

        3. Evaluate the employer's method for ensuring the confidentiality of employee medical records.

        4. When it is necessary to review employee medical records, ensure that they are obtained and remain confidential in accordance with 1913.10 and 1910.1020.

          Citation Guidance: If violations are found, CSHOs should cite the applicable section of 1910.1020 or 1926.33. These rules do not require creation of any records, only preservation and access requirements.

          Recent revisions to recordkeeping policies and procedures are described in CPL 02-00-135, Recordkeeping  Policies and Procedures Manual (RKM).

      7. Abrasive Blasting:

        In addition to the program elements described above, the following procedures apply specifically to abrasive blasting operations:

        1. Conduct monitoring to determine employee exposure to metals, such as: lead, arsenic, manganese, chromium, cadmium, copper, and magnesium.  (Abrasive blasters  may be exposed to metals either from the surface being blasted or from non-silica abrasive media.)

        2. The air sampling device (cyclone) must be placed within the breathing zone, outside of any protective equipment including the abrasive blasting hood.

        3. Conduct exposure monitoring of potentially exposed employees not engaged in abrasive blasting but still working in the area.

        4. Conduct noise exposure monitoring as appropriate.

        5. Determine whether the ventilation systems for abrasive blasting rooms and containment structures prevent escape of dust and provide prompt clearance of dust-laden air.

        6. Determine whether each blast cleaning nozzle is properly equipped with an operating valve that must be held open manually.

        7. For supplied-air respirators, evaluate breathing air quality and use.  For oil-lubricated compressors, ensure that the compressor is equipped with a high-temperature or carbon monoxide alarm, or both, to ensure that carbon monoxide levels remain below the PEL.  [Note: Using an abrasive blasting hood while wearing a filtering face piece respirator violates the NIOSH approval for both respirators.]

        8. When compressors are used to supply air, ensure that in-line absorbent beds are used and maintained.

        9. Review electrical grounding.

        10. Review pressure controls.

        11. Determine whether the abrasive blasters have adequate PPE, such as canvas or leather gloves and aprons, to protect against injury from material impact.

        12. Where an alternative abrasive material is being used such as glass beads, steel grit and shot, sawdust and shells, ensure that an appropriate evaluation of the hazards associated with the material has been conducted.

          Citation Guidance:  If overexposures to metals or noise are found, the CSHO should cite the applicable standard.

          If the ventilation system for a blast cleaning enclosure is found to be inadequately designed or ineffective at controlling dust, the CSHO should cite the applicable section of 1910.94(a).

          If blast cleaning nozzles are not properly equipped with operating valves that must be held open manually, the CSHO should cite 1910.244(b) or 1926.302(b)(10).

          Violations related to respiratory protection for abrasive blasting operations may be cited under 1910.94(a)(5).  Guidance is also contained in OSHA Directive CPL 02-00-120 (CPL 2-0.120), Inspection Procedures  for the Respiratory Protection  Standard.

          Violations related to personal protective equipment should be cited under 1910.94(a)(5), 1910.132, 1926.28, 1926.95, or 1926.100-103.

    3. Outreach.

      The OSHA Office of Training and Education, in conjunction with the Directorate of Enforcement Programs and the Office of Communications, will develop crystalline silica-related information and training materials. This information will be made available to the Regional Offices for distribution to the Area Offices and Consultation Program offices. Each Area Office/Region is encouraged to develop outreach  programs that will support their enforcement efforts.

      1. Suggested Outreach:

        Products and activities include the following:

        1. Letters and News Releases announcing implementation of the Silica National Emphasis Program.

        2. Seminars on silica-related topics, tailored for specific audiences, such as employers, employee groups, local trade unions, apprentice programs (e.g., masons, bricklayers, railroad employees), and equipment manufacturers. Local occupational medical staff can be invited to participate.

        3. Partnerships and Alliances, such as teaming employers within the same industry (e.g., foundries) to share successes and technical information concerning effective means of controlling and reducing or eliminating employee exposure to crystalline silica.

        4. Partnership and Alliance with groups representing non-English-speaking  employees such as Hispanic Contractors of America. Include silica-related information on OSHA's new Spanish-language website.

      2. Targeted Audiences for Outreach:

        1. Local employers engaged in silica-related work (refer to Appendix B for examples).

        2. Local employer associations, such as Associated General Contractors. Associated Builders and Contractors, Inc. and Shipbuilders Council of America.

        3. Local trade unions and apprenticeship programs (e.g., masons, bricklayers, railroad employees) and other employee groups.

        4. Independent contractors and the self-employed.

        5. Local hospitals, occupational health clinics, and other health organizations (e.g., state lung associations).

        6. Local professional associations (e.g., local safety councils).

        7. Temporary employment agencies providing employees to targeted employers (e.g., construction day laborers).

        8. Local building permitting authorities.

        9. Local newspapers, TV stations, trade magazines (can help inform the public and less accessible employers).

        10. Local government, such as health departments and department of transportation.

        11. Local suppliers of materials or services.

    4. Follow-up and Monitoring.

      1. Where citations are issued for overexposure to crystalline silica, follow-up site visits must be conducted to determine whether the company is eliminating silica exposures or reducing exposures below the PEL.  Where exposures can not feasibly be reduced below the PEL, engineering and administrative controls must be used to reduce exposures to the extent feasible and employees protected with the use of PPE.

      2. For those employers where follow-ups cannot be done, (i.e., construction sites or temporary abrasive blasting operations) the Area Office should request that the employer provide written updates documenting the progress of their abatement efforts per 1903.19.

      3. Once the necessary abatement verification  is received, a copy of the relevant information in the case file  will be sent to the National Office - Directorate of Enforcement Programs (see Appendix I).  Information in the case file will be distributed to the Office of Statistics for use as the Goal Indicator for silica.

    5. Coordination.

      1. National Office:

        This NEP will be coordinated by the Office of Health Enforcement (OHE), Directorate of Enforcement Programs (DEP).

      2. Field:

        Each Regional Administrator is required to name a coordinator for this NEP.

    6. Federal Agencies.

      This instruction describes a change that affects Federal Agencies .  Executive Order 12196, Section 1-201, and 29 CFR 1960.16 requires Federal Agencies to follow the enforcement policy and procedures contained in this Directive.

    7. NEP Evaluation.

      This NEP will be evaluated using data collected from case files and follow-up site visit reports submitted by each Area Office to the Office of Health Enforcement. In the interim, the method currently used by the Office of Statistics to evaluate how the Strategic Plan goals are being met will continue to apply. Once the Office of Statistics has received a reasonable number of case files and follow-up site visit reports, the data will be evaluated to determine the impact of OSHA inspections on the reduction of crystalline silica exposures at each work site.

    8. IMIS Coding Instructions.

      For each form that has a Strategic Plan field, "SILICA" will be entered in that field for all inspections.

      For inspections which are conducted under this NEP, for each form that has an NEP field, enter "SILICA" in the appropriate field (see below).

      Additionally, for situations where crystalline silica is used as the abrasive media when abrasive blasting, Optional Information "ABRASIVE" will be entered on all forms (see below).

      OSHA Form NEP Field Optional Information Strategic Plan
      Item Value Item Type ID Value Item Value
      1 25d SILICA 42 N 02 ABRASIVE 25f SILICA
      7 50 SILICA 46 N 02 ABRASIVE 52 SILICA
      36 36 SILICA 35 N 02 ABRASIVE 38 SILICA
      55 15 SILICA 19 N 02 ABRASIVE 17 SILICA
      90 30 SILICA 29 N 02 ABRASIVE 32 SILICA


      Consultation: Recording silica related visits will be done whenever a visit is made in response to this NEP. For each form that has an NEP field, enter "SILICA" for situations where crystalline silica is used. For situations where crystalline silica is used as the abrasive media when abrasive blasting, Optional Information "ABRASIVE" will be entered on all forms (see below).

        NEP Field Optional Information
      Form Item Value Item Type ID Value
      Request Form-20 25 SILICA 18 N 02 ABRASIVE
      Visit Form-30 28 SILICA 22 N 02 ABRASIVE



List of Appendices

Appendix A.  Background  Information on Silica

Appendix B.  Industries with Potential Overexposure to Crystalline Silica

Appendix C.  Guidelines for Air Sampling

Appendix D.  Cyclone Leak Test Procedure

Appendix E.  Conversion Factor  for Silica PELs in Construction and Maritime

Appendix F.  Employee Questionnaire

Appendix G.  Medical Monitoring Recommendations  for Employees Exposed to Crystalline Silica

Appendix H.  CSHO Checklist  for Conducting Silica-Related Inspections

Appendix I. Case File Components to be Sent to the National Office

Appendix J.  Bibliography





Appendix A: Background  Information on Silica

This appendix provides an overview of the following silica-related topics: the forms and sources of silica; common industrial uses of silica and workplaces with silica exposure; history  of silicosis ; and health effects associated with exposure.  The reference list at the end of this appendix, as well as the expanded bibliography in Appendix J, provide many sources that may prove useful to those interested in a more in-depth treatment of these topics.

Introduction

"Silica," is a term which refers broadly to the mineral compound silicon dioxide (SiO2).  Silica can be crystalline or amorphous.  Crystalline silica is significantly more hazardous to employees than amorphous silica.  In addition to causing the disabling and irreversible lung disease known as silicosis , crystalline silica has been classified as a human carcinogen by the International Agency for Research on Cancer (IARC ) [IARC, 1997].  As it is typically used in this document, "silica" refers specifically to crystalline silica.

Crystalline silica is characterized by a large scale, repeating pattern of silicon and oxygen atoms, as distinguished from the more random arrangement found in amorphous silica.  Abundant in the earth's crust, crystalline silica is a basic component of most classes of rock.  Naturally-occurring forms of amorphous silica include diatomaceous earth (the skeletal remains of marine organisms) and vitreous silica or volcanic glass [Markowitz and Rosner, 1995; Davis, 1996].

Forms and Sources of Crystalline Silica

Crystalline silica occurs in three primary mineralogical forms, or polymorphs-quartz, cristobalite, and tridymite.  Silica is also called "free silica," to distinguish it from the silicates, which are minerals containing silicon dioxide bound to one or more cations [Beckett et al., 1997].

Quartz is by far the most common form of naturally-occurring silica [Davis, 1996; IARC , 1997]. Cristobalite and tridymite, which are molecularly identical to quartz, are distinguishable by their unique crystalline structures.  They are less stable than quartz, thus accounting for the dominance of the quartz form. Quartz itself exists as either of two sub-polymorphs, alpha-quartz (also known as low quartz), and beta-quartz (high quartz).  Alpha-quartz is the thermodynamically stable form of crystalline silica and accounts for the overwhelming portion of naturally-occurring crystalline silica [IARC, 1997].

Quartz is a major component of soils and is readily found in both sedimentary and igneous rocks, although the quartz content varies greatly from one rock type to another.  For instance, granite contains on average about 30 percent quartz, and shales contain about 20 percent quartz.  Natural stone, such as beach sand or sandstone, may be nearly pure quartz [IARC , 1997; Davis, 1996].

Cristobalite and tridymite are natural constituents of some volcanic rock, and man-made forms result from direct conversion of quartz or amorphous silica that has been subjected to high temperature or pressure.  Diatomaceous earth, composed of amorphous silica, crystallizes during heating (calcining), yielding a calcined product that contains as much as 75 percent cristobalite.  Cristobalite is also found in the superficial layers of refractory brick that has been repeatedly subjected to contact with molten metal [Markowitz and Rosner, 1995; Ganter, 1986; Cheng et al., 1992; Bergen et al., 1994].

Major Industrial Sources of Crystalline Silica Exposure

Crystalline silica is an important industrial material and occupational exposure occurs across a broad range of industries, including mining, manufacturing, construction, maritime, and agriculture (see Appendix B for a listing of industries and Standard Industrial Classifications with potential for significant occupational exposure).  Processes associated historically with high rates of silicosis  include sandblasting, sand-casting foundry operations, mining, tunneling, and granite cutting.

Crystalline silica, in the form of finely ground quartz sand as an abrasive blasting agent, is used to remove surface coatings prior to repainting or treating, a process that typically generates extremely high levels of airborne respirable crystalline silica.  A 1992 report published by the National Institute for Occupational Safety and Health (NIOSH) estimates that there are more than one million U.S. employees who are at risk for developing silicosis , and of these employees, more than 100,000 are employed as sandblasters.  Abrasive blasting  is performed in a wide variety of different industries; the construction industry employs the largest number of employees as abrasive blasters, concentrated in the special trades [NIOSH 92-102; CDC, 1997].

In addition to abrasive blasting, construction employees perform numerous other activities that may result in significant silica exposure, including tunnel and road construction, excavation and earth moving, masonry and concrete work, and demolition [IARC , 1997].  Foundry employees, primarily in iron and steel foundries, may be exposed to crystalline silica throughout the metal-casting process, including the production of sand-based molds and cores, shakeout and knockout, and finishing and grinding operations.

Crystalline silica, primarily as quartz, is a major component of the sand, clay, and stone raw materials used to manufacture a variety of products, including concrete, brick, tile, porcelain, pottery, glass, and abrasives.  The powdered form of quartz, also called silica flour, is used in the manufacture of fine china and porcelain.  Finely ground crystalline silica is also used as a functional filler in the manufacture of paints, plastics, and other materials.  The rock crystal form of quartz is of great value to the electronics industry.

Agricultural employees perform activities, including plowing and harvesting, that may generate elevated silica levels.  However, OSHA does not regulate crystalline silica exposure on farms with fewer than ten employees and exposure data for this population is lacking [Linch et al., 1998].  On the other hand, OSHA does regulate crystalline silica exposure in the agricultural services sector, and crystalline silica exposures have been documented in the sorting, grading, and washing areas of food processing operations for crops such as potatoes and beans.

Cristobalite, as calcined diatomaceous earth, is used as a filler in materials such as paints and as a filtering media in food and beverage processing.  Maintenance and trades personnel who repair and replace refractory brick linings of rotary kilns and cupola furnaces may be exposed to significant levels of quartz, as well as cristobalite and tridymite.  These kilns and furnaces are found in glass, ceramics, and paper manufacturing facilities as well as foundries [Markowitz and Rosner, 1995].

The industries described above, (see Appendix B) represent the major industrial sources of crystalline silica exposure.  However, there are numerous other operations in which silica may be used or otherwise encountered, and it is important to be aware of the risk of silicosis  in industries not previously recognized to be at risk.

History of Silicosis

Silicosis is one of the world's oldest known occupational diseases; reports of employees with the disease date back to ancient Greece.  By 1800, there were numerous common names for the lung disease now known as silicosis .  The names frequently referred to the affected laborers' trade, such as grinders' asthma, grinders' rot, masons' disease, miners' asthma, miners' phthisis, potters' rot, sewer disease, and stonemasons' disease.  Despite its different names through the centuries, silicosis is a single disease with a single cause-exposure to respirable crystalline silica dust.

During the 1920s, the health risks of the "dusty" trades, in particular the granite industry, emerged as a significant public health concern, and by 1930 silicosis  was considered the most serious occupational disease in the United States.  During the 1930s and 1940s, the granite industry was the focus of a major effort to alleviate dusty conditions and create a safer working environment [Rosner and Markowitz, 1994].  However, as the more extreme silica hazards were brought under control, attention shifted away from silica to other occupational health hazards.  Nonetheless, as the studies described below indicate, in recent decades silicosis has continued to pose a significant health threat to employees in a variety of occupations, including but not limited to construction, foundries, and sandblasting.  It is important to be aware of the possible risk of silicosis in workplaces not previously recognized to be at risk.
  • Silicosis was listed as the underlying cause of death in 6,322 fatalities in the United States from 1968 through 1990, according to a study reviewing multiple-cause-of-death data from the National Center for Health Statistics.  The total number of U.S. deaths with mention of silicosis  for that period was 13,744.  The study found that 69 percent of the deaths due to silicosis were concentrated in 12 states: California, Colorado, Florida, Illinois, Michigan, New Jersey, New York, Ohio, Pennsylvania, Virginia, West Virginia, and Wisconsin.  The construction industry accounted for more than 10 percent of the total silicosis-related deaths, and iron and steel foundries accounted for another 5.4 percent [Bang et al., 1995].

  • Death certificates for approximately 868 men and 46 women listed silicosis  as the underlying cause of death in non-mining occupations, according to a study that reviewed death certificates for the period 1985 to 1992.  The researchers focused on death certificates that provided an entry for indicating the potential for substantial silica exposure, reviewing a total of 411,404 death certificates for men and 30,563 for women [Walsh, 1999].

  • A ten-year study (1985 to 1995) of Michigan employees found that nearly 80 percent of the 577 confirmed cases of silicosis  occurred in industries in the Standard Industrial Classification (SIC) 3300, Primary Metals, which encompasses iron and steel foundries [Rosenman et al., 1997].  In another study, foundry employees whose lungs exhibited radiographic changes consistent with silicosis were concentrated in four primary job assignments: core making, mold making, core knockout, and cleaning/finishing.  The study was conducted at a Midwestern gray iron foundry that has produced automotive engine blocks since 1949; the researchers analyzed medical records and silica exposure data for 1,072 current and retired employees with at least five years of employment as of June 1991.  Radiographic readings consistent with silicosis were also correlated with the number of years at the foundry, smoking habits, and silica exposure levels [Rosenman et al., 1996].

  • In the mid-1990s, there were two cases of accelerated silicosis  in relatively young sandblasters following short periods of extremely high crystalline silica exposures.  In 1995, a 36-year-old man who had sandblasted oil field tanks in Western Texas for 36 months died from respiratory failure, eleven years after his initial exposure to crystalline silica.  A second sandblaster at the same facility, a 30-year-old man who had worked as a sandblaster from 1986 to 1990, died in 1996,  ten years after his initial exposure [CDC, 1998].  Both of these sandblasters died from progressive massive fibrosis, an advanced stage of silicosis.
Adverse Health Effects of Crystalline Silica Exposure

Pulmonary silicosis has historically been the disease most well-known as being caused by the inhalation of respirable crystalline silica particles.  Additionally, there is evidence that exposure to crystalline silica-containing dusts causes or is associated with the following conditions:  lung cancer, tuberculosis, chronic obstructive pulmonary disease (including emphysema and bronchitis), autoimmune diseases or immunologic disorders, chronic renal disease, and subclinical renal changes [NIOSH, 2002].

Silicosis

Silicosis is a fibrotic disease of the lungs caused by the inhalation of crystalline silica dust.  It is a type of pneumoconiosis, which is a general term for chronic lung disease that occurs when certain particles are inhaled and deposited deep in the lung.

There are two main types of silicosis , chronic silicosis (also called "classical" or "nodular" silicosis) and acute silicosis, medically referred to as silico-proteinosis or alveolar lipoproteinosis-like silicosis.  Chronic silicosis, by far the most common form of the occupational disease, typically appears 20 to 40 years after initial exposure and tends to progress even after exposure ceases.  Accelerated silicosis is a variant of chronic silicosis but develops after more intense exposure to crystalline silica; it is characterized by earlier onset (within 5 to 15 years of initial exposure) and more rapid progression of disease than chronic silicosis [Weill et al., 1994].

Acute silicosis  results from an overwhelming exposure to silica and the symptoms become manifest in as little time as a few weeks after exposure.  Acute silicosis appears to be distinct from the other forms of silicosis, possibly involving an immune mechanism not associated with either accelerated or chronic silicosis.  This disease, though rare, is invariably fatal. Outbreaks of acute silicosis have occurred among sandblasters and silica flour mill employees [Peters, 1986].

The development of silicosis  is dependent on the size of the crystalline silica dust particle, the dust concentration, and the duration of exposure.  Crystalline silica particles smaller than 10 micrometers (µm) in diameter, so-called respirable particles, are particularly hazardous, because they easily pass through the tracheobronchial tree and are deposited in the deepest recesses of the lungs, the alveolar structures.  Particles larger than 10 mm in diameter are trapped in the nose or the mucous lining of the airway and are removed by the mucociliary escalator.

Chronic silicosis  has an early manifestation of a dry or non-productive cough when there is continued exposure to the inhaled irritant.  The cough then becomes prolonged and distressing, with sputum production as the disease advances.  Initially, breathlessness occurs while exercising, but progresses to shortness of breath during normal activity [Porth, 1994].  Wheezing typically only occurs when conditions such as chronic obstructive bronchitis  or asthma are also present.  Advanced states of silicosis include pneumothorax and respiratory failure.  Respiratory symptoms increase with the progression of silicosis [Wang, 1999].

A rapid increase in the rate of synthesis and deposition of lung collagen has also been seen with the inhalation of crystalline silica particles.  The collagen formed is unique to silica-induced lung disease and is biochemically different from normal lung collagen [Olishifski and Plog, 1988].

Silicosis in all its forms is incurable and causes significant impairment or death.  Therefore, eliminating or controlling occupational exposure to respirable crystalline silica is critical to prevention of the disease.

Lung Cancer

The International Agency for Research on Cancer [IARC, 1997] classifies crystalline silica inhaled in the form of quartz or cristobalite from occupational source as "carcinogenic to humans (Group 1)."  However, in making the overall evaluation, the IARC Working Group noted "that carcinogenicity in humans was not detected in all industrial circumstances studied." The Working Group also stated: "Carcinogenicity may be dependent on inherent characteristics of the crystalline silica or on external factors affecting its biological activity or distribution of its polymorphs."

The IARC  analysis included studies of U.S. gold miners, Danish stone industry employees, U.S. granite shed and quarry employees, U.S. crushed stone  industry employees, U.S. diatomaceous earth employees, Chinese refractory brick makers, Italian refractory brick makers, U.K. pottery makers, Chinese pottery makers and cohorts of registered silicotics from North Carolina and Finland.  Most of these studies found a statistically significant association between occupational exposure to crystalline silica and lung cancer .

Tuberculosis

Epidemiologic studies have firmly established the association between TB and silicosis.  Some studies have indicated that employees who do not have silicosis but who have had long exposures to silica dust may also be at increased risk of developing TB [NIOSH, 2002].

Individuals with chronic silicosis  are more susceptible to developing active tuberculosis  than the general population.  However, it is not clear whether low-level exposure to silica, in cases where silicosis has not developed, also predisposes employees to tuberculosis [Davis, 1996].

Chronic Obstructive Pulmonary Disorder

Epidemiologic studies have shown that occupational exposure to respirable crystalline silica is associated with chronic obstructive pulmonary disease, including bronchitis and emphysema.  The findings from some of these studies suggest that emphysema and bronchitis may occur less frequently or not all in nonsmokers.  Epidemiologic studies have also found significant increases in mortality from nonmalignant respiratory disease, a category that includes silicosis, emphysema, and bronchitis, as well as some other related pulmonary diseases [NIOSH, 2002].

Immunologic Disorders and Autoimmune Diseases

Several epidemiologic studies have found statistically significant increases in mortality from or cases of immunologic disorders and autoimmune diseases in employees exposed to silica.  These disorders and diseases include scleroderma (a rare multisystem disorder characterized by inflammatory, vascular, and fibrotic changes usually involving the skin, blood vessels, joints, and skeletal muscle), rheumatoid arthritis, systemic lupus erythematosus (lupus), and sarcoidosis (a rare multisystem granulomatous disease characterized by alterations in the immune system) [NIOSH, 2002].

Renal Disease  

Epidemiological studies report statistically significant associations between occupational exposure to silica dust and several renal diseases or effects, including end-stage renal disease morbidity (including that caused by glomerular nephritis, chronic renal disease mortality, and Wegener's granulomatosis (systemic vasculitis often accompanied by glomerulonephritis) [NIOSH, 2002].

Stomach and Other Cancers  

There is some evidence from studies of various occupational groups exposed to crystalline silica of statistically significant excesses of mortality from stomach or gastric cancer.  However, most of these studies did not adjust for confounding factors and possible exposure-response relationships were not assessed.  Similar issues with confounding and lack of exposure-response assessment exist for the infrequent reports of statistically significant numbers of excess deaths or cases in silica-exposed employees of other nonlung cancers such as nasopharygeal or pharyngeal, salivary gland, liver, bone, pancreatic, skin, esophageal, digestive system, intestinal or peritoneal, lymphopoietic or hematopoietic, brain, and bladder [NIOSH, 2002].

Summary

As these health findings indicate, crystalline silica exposure is associated with a number of diseases, in addition to silicosis. Silica exposure continues to pose substantial risks to employees, centuries after it was first identified as an occupational hazard.  The only way to prevent disease is to eliminate exposure to crystalline silica or reduce crystalline silica exposure to safe levels.

References

ACGIH (2000) 2000 TLVs® and BEIs®.  Threshold Limit Values for Chemical Substances and Physical Agents and Biological Exposure Indices. American Conference of Governmental Industrial Hygienists. Cincinnati, OH.

Archer, C., Gordon, D.A. (1996) Silica and Progressive Systemic Sclerosis (Scleroderma ): Evidence for Workers' Compensation Policy. American Journal of Industrial Medicine. 29:533-538.

Bang, K.M., Althouse, R.B., Kim, J.H., et al. (1995) Silicosis Mortality Surveillance in the United States, 1968-1990.  Appl. Occup. Environ. Hyg. 10(12):1070-1074.

Beckett, W., et al. (1997) Adverse Effects of Crystalline Silica Exposure. Statement of the American Thoracic Society, Medical Section of the American Lung Association. American Journal of Respiratory and Critical Care Medicine. 155:761-765.

Bergen, E.A.V.D., Rocchi, P.S.J., Boogaard, P.J. (1994) Ceramic Fibers and other Respiratory Hazards during the Renewal of the Refractory Lining in a Large Industrial Furnace.  Appl. Occup. Environ. Hyg. 9(1):32-35.

Boujemaa, W., Lauwerys, R., Bernard, A. (1994) Early Indicators of Renal Dysfunction in Silicotic Workers.  Scand J Work Environ Health. 20:180-3.

Centers for Disease Control and Prevention. (1998) Silicosis Deaths Among Young Adults - United States, 1968-1994. MMWR 47(16):331-335.

Centers for Disease Control and Prevention. (1997) Silicosis Among Workers Involved in Abrasive Blasting - Cleveland, Ohio, 1995. MMWR 46(32):744-747.

Checkoway, H., Heyer, N.J., Demers, P.A., et al. (1993) Mortality among workers in the diatomaceous earth industry. Brit. Jour. Ind. Med. 50:586-597.

Cheng, R.T., McDermott, H.J., Gia, G.M., et al. (June 1992) Exposure to Refractory Ceramic Fiber in Refineries and Chemical Plants. Appl. Occup. Environ. Hyg. 7(6):361-367.

Davis, G.S. (1996)  "Silica," in Occupational and Environmental Respiratory Disease, Mosby-Yearbook Inc., St. Louis, MO, eds. Harber, P., Schencker, M. B., Balmes, J.R.

Gantner, B.A. (1986) Respiratory Hazard from Removal of Ceramic Fiber Insulation from High Temperature Industrial Furnaces. Am. Ind. Hyg. Assoc. J. 47(8):530-534.

Goldsmith, D.F. (1994) Silica exposure and pulmonary cancer. In: Epidemiology of Lung Cancer,  245-298, Samet, J.M. ed.  New York: Marcel Dekker, Inc.

IARC . (1997) IARC Monographs on the Evaluation  of Carcinogenic Risks to Humans. Silica, Some Silicates, Coal Dust and para-Aramid Fibrils. Vol. 68. Lyon, France.  International Agency for Research on Cancer, World Health Organization.

Linch, K.D., Miller, W.E., Althouse, R.B., Groce, D.W.,  Hale, J.M. (1998)  Surveillance of Respirable Crystalline Silica Dust using OSHA Compliance Data (1979-1995). American Journal of Industrial Medicine. 34:547-558.

Lippmann, M. (1995) Exposure Assessment Strategies for Crystalline Silica Health Effects. Appl. Occup. Environ. Hyg. 10(12):981-990.

National Institute for Occupational Safety and Health, Publication No. 92-102 (1992) Hazard Alert: Preventing Silicosis and Deaths from Sandblasting.

Olishifski, L.B.; Plog, B.A. (1988) Overview of Industrial Hygiene, Fundamentals of Industrial Hygiene 3rd  ed. Chicago, National Safety Council.

Peters, J.M. (1986) Silicosis. Occupational Respiratory Diseases. Division of Respiratory Disease Studies, Appalachian Laboratory for Occupational Safety and Health, ed. J.A. Merchant, published by the National Institute for Occupational Safety and Health.

Porth, C.M. (1994) Pathophysiology: Concepts of Altered Health States, 4th ed. Unit V, Ch. 26 & 27, J.B. Lippincott Co., Philadelphia.

Proctor, N.H., Hughes, J.P., Fischman, M.L. (1988) Chemical Hazards of the Workplace. 2nd ed. J.B. Lippincott Co. Philadelphia.

Rapiti, E., Speranti, A., Miceli, M., et al. (1999) End Stage Renal Disease  Among Ceramic Workers Exposed to Silica. Occup. Environ. Med. 56:559-561.

Rosenman, K.D., Reilly, M.J., Kalinowski, D.J., Watt, F.C. (1997) Silicosis in the 1990s. Chest. 111(3):779-782.

Rosenman, K.D., Reilly, M.J., Rice, C., et al. (1996) Silicosis Among Foundry Workers: Implications for the Need to Revise the OSHA Standard. Am. J. Epidemiol. 144(9):890-900.

Rosner, D., Markowitz, G. (1994) Deadly Dust: Silicosis and the Politics of Occupational Disease in Twentieth-Century America. Princeton: Princeton University Press.

Schluter, D.P. (1994) Silicosis and Coal Worker's Pneumoconiosis. Occupational Medicine. eds. Zens C., et al. 3rd ed. St Louis, Mosby-Year Book, Inc.

Starzynski, Z., Marek, K., Kujawska, A., Szymczak, W. (1996) Mortality Among Different Occupational Groups of Workers with Pneumoconiosis: Results From a Register-Based Cohort Study. Am. J. of Ind. Med. 30:718-725.

Steenland, K., Mannetje, A., Boffetta, P., Stayner,L., Attfield, M., Chen, J., Dosemeci, M., DeKlerk, N., Hnizdo, E., Koskela, R., and Checkoway, H. (2001). Pooled exposure-response analyses and risk assessment for lung cancer  in 10 cohorts of silica-exposed workers: an IARC  multicentre study.  Cancer Causes and Control 12:773-784.

Walsh, S.J. (1999) Effects of Non-mining Occupational Silica Exposures on Proportional Mortality from Silicosis and Systemic Sclerosis. The Journal of Rheumatology. 26(10):2179-2185.

Wang, X., Yano, E., Nonaka, K., et al. (1997) Respiratory Impairments Due to Dust Exposure: A Comparative Study Among Workers Exposed to Silica, Asbestos, and Coal Mine Dust. Am. J. of Ind. Med. 31:495-502.

Wang, X., Yano, E. (1999) Pulmonary Dysfunction in Silica-Exposed Workers: A Relationship to Radiographic Signs of Silicosis and Emphysema. Am. J. of Ind. Med. 36:299-306.

Weill, H., Jones, R.N., Parkes, W.R. (1994) Silicosis and Related Diseases, in Occupational Lung Disorders, 3rd ed., Butterworth-Heinemann Ltd., Oxford, England.

Weill, H., McDonald, J.C. (1996) Exposure to Crystalline Silica and Risk of Lung Cancer: The Epidemiological Evidence. Thorax. 51:97-102.

Winter, P.D., Gardner, M.J., Fletcher, A.C., Jones, R.D. (1990) A mortality follow-up study of pottery workers: Preliminary findings of lung cancer. In: Occupational Exposure to Silica and Cancer Risk  (IARC  Scientific Publications, No. 97), 83-94, Simonato, L., et al. eds. International Agency for Research on Cancer. Lyon.





Appendix B:  Industries with Potential Overexposure to Crystalline Silica

This appendix contains a list of industries in which employees may be exposed to elevated levels of crystalline silica.  The list is based on a review of inspection data from OSHA's Integrated Management Information System (IMIS) for crystalline silica (quartz), for the period January 1996 through March 2007.  This table is intended to show the range of industries in which crystalline silica exposure may occur, but should not be considered to be an exhaustive listing.  Employee exposure to crystalline silica may occur in industries not listed here.  Likewise, crystalline silica exposure does not occur in all establishments encompassed within these North American Industry Classification System (NAICS) or Standard Industrial Classification (SIC) codes.

Industries with Crystalline Silica Exposure, 1996-2007
1987 SIC Code1 1987 SIC Industry Title 2002 NAICS Code2
1521 General Contractors-Single Family Houses 236115, 236118
1522 General Contractors-Residential Buildings Other Than Single-Family 236115, 236118
1541 General Contractors-Industrial Buildings and Warehouses 236210, 236220
1611 Highway and Street Construction, Except Elevated Highways 237310
1622 Bridge, Tunnel, and Elevated Highway Construction 237310, 237990
1623 Water, Sewer, Pipeline, and Communications and Power Line Construction 237110, 237120, 237130
1629 Heavy Construction, n.e.c. 236210, 237110, 237120, 237130, 237990
1721 Painting and Paper Hanging* 237310, 238320
1741 Masonry, Stone Setting, and Other Stone Work 238140
1742 Plastering, Drywall, Acoustical, and Insulation Work 238310
1761 Roofing, Siding, and Sheet Metal Work 238160, 238170, 238390
1771 Concrete Work 238110, 238140, 238990
1794 Excavation Work 238910
1795 Wrecking and Demolition Work 238910
1799 Special Trade Contractors, n.e.c. 236220, 237990, 238150, 238190, 238290
3251 Brick and Structural Clay Tile 327121, 327331
3253 Ceramic Wall and Floor Tile 327122
3255 Clay Refractories 327124
3261 Vitreous China Plumbing Fixtures and China and Earthenware Fittings and Bathroom Accessories 327111
3262 Vitreous China Table and Kitchen Articles 327112
3264 Porcelain Electrical Supplies 327113
3269 Pottery Products, n.e.c. 327112
3271 Concrete Block and Brick 327331
3272 Concrete Products, Except Block and Bricks 327332, 327390, 32799
3273 Ready-Mixed Concrete 327320
3281 Cut Stone and Stone Products 327991
3291 Abrasive Products 327910, 332999
3299 Nonmetallic Mineral Products, n.e.c. 327112, 327420, 327999
3312 Steel Works, Blast Furnaces (Including Coke Ovens), and Rolling Mills 324199, 331111, 331221
3321 Gray and Ductile Iron Foundries 331511
3322 Malleable Iron Foundries 331511
3325 Steel Foundries, n.e.c. 331513
3334 Primary Production of Aluminum 331312
3365 Aluminum Foundries 331524
3366 Copper Foundries 331525
3369 Nonferrous Foundries, Except Aluminum and Copper 331528
3431 Enameled Iron and Metal Sanitary Ware 332998
3441 Fabricated and Structural Metal* 332312
3443 Fabricated Plate Work (Boiler Shops)* 332313, 332410, 332420
3444 Sheet Metal Work* 332321, 332322, 332439, 333415
3471 Electroplating, Polishing, Anodizing, and Coloring* 332813
3479 Coating, Engraving, and Allied Services, n.e.c.* 332812, 339911, 339912, 339914
3531 Construction Machinery and Equipment* 333120, 333923, 336510
3599 Industrial and Commercial Machinery and Equipment* 332710, 332813, 332999, 333319, 333999, 334519, 336399
3715 Truck Trailers* 336212
5032 Brick, Stone, and Related Construction Materials3 423320, 425110, 425120, 444190
7532 Top, Body, and Upholstery Repair Shops and Paint Shops* 811121
*Crystalline silica exposure primarily from abrasive blasting operations

1 Standard Industrial Classification Manual, 1987.  Executive Office of the President, Office of Management and Budget.

2 North American Industry Classification System, United States, 2002.  Executive Office of the President, Office of Management and Budget.

3 This industry may be subject to OSHA Instruction CPL 02-00-051 - Enforcement Exemptions and Limitations under the Appropriations Act (or a subsequent version).

Source: Federal OSHA Inspection Data for Silica (Code 9010-Quartz) compiled in the OSHA Integrated Management Information System (IMIS), from 01/01/1996 through 03/31/2007.



Appendix C - Guidelines for Air Sampling

This appendix summarizes the procedures for collecting air samples of respirable crystalline silica, contained in OSHA sampling and analytical method ID-142.  Although OSHA ID-142 applies to the collection of quartz and cristobalite, tridymite can also be collected and analyzed using this method if the appropriate reference material and diffraction pattern are used.  Compliance Safety and Health Officers (CSHOs) should consult the method directly for detailed information.  Additionally, information on respirable dust samplers and crystalline silica sampling is contained in the OSHA Technical Manual, Section II: Chapter I.

Sampling Equipment

1.   A 5-µm pore size, 37-mm diameter polyvinyl chloride (PVC) filter, preceded by a 10-mm nylon Dorr-Oliver cyclone, is used with a personal sampling pump for the collection of airborne respirable crystalline silica.  Note:  SKC metal cyclones shall not be used for sampling respirable dust (OSHA Instruction TED 01-00-015 {TED1-0.15A}).  The metal cyclones do not "cut" the appropriate particle size as required by the OSHA standard.

2.   CSHOs may obtain pre-weighed PVC filters by contacting OSHA's Salt Lake Technical Center (SLTC) or Cincinnati Technical Center (CTC).

Sampling Instructions

1. Calibrate the personal sampling pump to a flow rate of 1.7 liters per minute (L/min), with a representative sampler assembly (cyclone, filter, etc.) in-line.  The pump shall be calibrated before and after each use.  Refer to the OSHA Technical Manual (OTM), Section II: Chapter 1, for detailed information on pump calibration when sampling with cyclones.  The recommended and maximum sampling time is 480 minutes (resulting in a sample air volume of 816 liters at 1.7 L/min.), and the minimum sample time is 240 minutes (408 liters collected at 1.7 L/min.).

2. Before and after each use, clean the cyclone gently, taking care not to scratch it. A leak test must be conducted on a cyclone at least once a month with regular usage. Refer to the OSHA OTM Section 1: Chapter 1. Also, Appendix D summarizes the Cyclone Leak Test Procedure.

3. The cyclone shall be positioned outside of the employee's personal protective equipment but within the breathing zone.  Do not allow the cyclone to be inverted during or after sampling.  Maintain the cyclone in an upright position until the filter is removed from the cyclone.

4. Check the pump and sampling assembly periodically, to verify pump performance and monitor particulate loading on the sample filter.  Filters should be replaced when employees move to another task or activity, or if observation during sampling suggests possible filter overload (greater than 3 mg.).  [Note:  The CSHO should not enter an area while the abrasive blasting operation is active.]

5. When submitting the sample to the laboratory, indicate whether the requested analysis is for quartz, cristobalite, or both.  Operations in which the material has been heated to high temperatures generally should be analyzed for both.  When other airborne compounds are known or suspected to be present, such information, including the suspected identities, should be provided to the laboratory.  Where possible, a copy of the MSDS should be submitted to aid in identifying interferences. Potential analytical interferences are listed in Appendix A of OSHA ID-142. A partial listing follows:
  • Aluminum phosphate
  • Feldspars (microcline, orthoclase, plagioclase)
  • Graphite
  • Iron carbide
  • Lead sulfate
  • Micas (biotite, muscovite)
  • Montmorillonite
  • Potash
  • Sillimanite
  • Silver chloride
  • Talc
  • Zircon (Zirconium silicate)
6. Identify and submit an appropriate blank filter from each lot of filters used.

7. Obtain bulk samples  in accordance with standard procedures described in the OTM, Section II: Chapter 1.  The bulk sample should be representative of the airborne silica content of the work environment, e.g., from settled dust.  A bulk sample of the raw material should be collected to evaluate compliance with the Hazard Communication  standard.  The type of bulk sample shall be stated on the OSHA-91 form and cross-referenced to the appropriate air samples.

Determining Compliance with the PEL for Respirable Crystalline Silica

The General Industry permissible exposure limit (PEL) for respirable dust containing crystalline silica (as quartz), codified at 29 CFR 1910.1000, is determined individually for each sample, according to the following formula:
General Industry permissible exposure limit (PEL) for respirable dust containing crystalline silica (as quartz),

The PEL can be calculated either by following the steps below, or by accessing the "Advisor Genius" on-line at the OSHA web site.  The Advisor Genius performs the calculations for a respirable dust sample and yields three values: the PEL for the sample, the respirable dust exposure result, and the severity.

To determine the PEL for an air sample containing respirable crystalline silica:

1. Obtain the respirable dust concentration for the sample.  The weight of the respirable dust in the air sample (expressed as mg or µg) is the net filter weight gain, as determined by the industrial hygienist or the laboratory. The sample air volume is then used to express the concentration of respirable dust in air, as mg of respirable dust per cubic meter of air (mg/m³), as follows:
Obtain the respirable dust concentration for the sample

2. Obtain the percent respirable crystalline silica (e.g., as quartz) in the respirable dust sample, determined analytically by the laboratory and derived as follows:
Obtain the percent respirable crystalline silica

3. Calculate the PEL for the sample, using the reported percent respirable quartz, from no. 2 above, as follows:
Calculate the PEL for the sample

4. To determine whether there is an overexposure, compare the PEL, calculated in no. 3, with the sample respirable dust reading (from no. 1).  The severity ratio is determined by the following formula:
The severity ratio is determined by the following formula

5. Calculate the Lower Confidence Limit (LCL) by subtracting the Sampling and Analytical Error (SAE) from the severity:

LCL = Severity - SAE

If the LCL is greater than 1, there is a greater than 95% confidence that the sampled employee's exposure exceeded the PEL, and the employee was, therefore, overexposed to respirable dust containing crystalline silica as quartz.

Other factors may have to be considered before arriving at a final exposure value.  For example, the Time Weighted Average (TWA) calculation may require combining two or more sample results and adjusting to an 8-hour workday.  Consult the OTM, Section II: Chapter 1 for procedures to determine the PEL when the employee is exposed to different types of respirable crystalline silica (i.e., quartz, cristobalite, and tridymite) during the course of a single work shift.

References

Occupational Safety and Health Administration (OSHA). OSHA ID-142. Quartz and Cristobalite in Workplace Atmospheres (XRD). December 1996.

Occupational Safety and Health Administration (OSHA), OSHA Technical Manual TED 01-00-015 (TED 1-0.15A).  Section II: Sampling, Measurement Methods and Instruments, Chapter I: Personal Sampling for Air Contaminants, Appendix II:1-5. Sampling for Special Analyses, Samples Analyzed by X-Ray Diffraction, Air Samples, January 20, 1999.





Appendix D: Cyclone Leak Test Procedure

This section summarizes procedures for leak testing of the Dorr-Oliver cyclone samplers used for collecting respirable dust.  Further details on this procedure are contained in the Cyclone Leak Test Procedure (CLTP) available through the OSHA Cincinnati Technical Center (OSHA, 1997). Compliance Safety and Health Officers (CSHOs) should review the entire leak test procedure before conducting the leak test as summarized below.  See the CLTP for more specific procedures regarding leak tests.

Nylon Part Inspection
  • Disassemble the cyclone assembly, clean it, and inspect it for cracks and worn fit between parts.  Take care not to scratch the inside surface of the cyclone chamber.

  • Replace any worn or cracked units or parts.
O-Ring, Tubing, and Filter Leak Test
  • Connect the entire cyclone assembly (minus the cyclone body) to the pressure gauge and aspirator, maintaining the normal spacing between the plastic filter adaptor (coupler) and the vortex finder.

  • Seal the cyclone vortex finder opening by placing an airtight cap or your fingertip over the hole.

  • Hold the cyclone assembly together with one hand.

  • With your other hand, squeeze and gently release the aspirator bulb until the pressure gauge reads between 4" H2O and 10" H2O, then fold the tubing halfway between the "Tee" fitting and the aspirator. If the pressure reading is beyond full scale, release the vacuum and try again.

  • Observe the pressure gauge reading for 30 seconds.  If the pressure drops less than 25 percent, the leakage is acceptable and the unit passes the leak test.  If the pressure drops more than 25 percent, corrective action is necessary.  Sources of leaks include worn or damaged O-rings, cracked or ill-fitting tubing, and leaky pre-weighed filter cassettes.

Note:  Leaks between the filter input and the air sampling pump are more disruptive than leaks at the plastic filter adaptor O-rings.

Final Pump-Fault Leak Test
  • Connect the cyclone assembly to the pump in the normal sampling configuration with the air sampling pump running at 1.7 L/min.

  • Close the inlet to the cyclone with tape or a finger.  If the pump bears down and goes into a fault mode, the assembly passes this final, but crude, pump-fault leak test.
Reference

Occupational Safety and Health Administration (OSHA). Cyclone Leak Test Procedure.  OSHA Cincinnati Technical Center.  September 15, 1997.




Appendix E: Conversion Factor for Silica PELs in Construction and Maritime

The crystalline silica permissible exposure limits (PELs) for the construction and maritime industries, at 29 CFR 1926.55(a) and 1915.1000 respectively, are expressed in terms of millions of particles per cubic foot (mppcf).  These PELs are based on a particle count method long rendered obsolete by respirable mass (gravimetric) sampling, which yields results reported in milligrams per cubic meter (mg/m3).  In contrast with the construction and maritime PELs, the crystalline silica PELs for general industry are based on gravimetric sampling, and are the only methods currently available to OSHA compliance personnel.  Since the construction and maritime PELs are expressed in terms of mppcf, the results of the gravimetric sampling must be converted to an equivalent mppcf value.

In order to determine a formula for converting from mg/m3 to mppcf, OSHA requested assistance from the National Institute for Occupational Safety and Health (NIOSH).  Based on its review of published studies comparing the particle count and gravimetric methods, NIOSH recommended a conversion factor of 0.1 mg/m3 respirable dust to 1 mppcf.  OSHA has determined that this conversion factor should be applied to silica sampling results used to characterize exposures in construction and maritime operations.  The following examples illustrate how the conversion factor should be applied to enforce the current PEL for crystalline silica (quartz) in the construction and maritime industries.

Reference Formulas
  1. Construction/Maritime PEL for Crystalline Silica (Quartz):
    Construction/Maritime PEL for Crystalline Silica (Quartz)
  2. General Industry PEL for Crystalline Silica (Quartz):
    General Industry PEL for Crystalline Silica (Quartz)
  3. OSHA-adopted conversion factor:

    1 mppcf = 0.1 mg/m3 respirable dust           or
    1 mg/m3 = 10 mppcf respirable dust

    Example 1: A sample is obtained for a jackhammer operator, using the gravimetric sampling method specified in OSHA ID-142.  The sample is run for 240 minutes at a flow rate of 1.7 liters per minute (L/min), yielding a total sample volume of 0.408 m3.  The respirable dust collected on the filter is determined to weigh 0.857 mg, resulting in a respirable dust concentration of 2.1 mg/m3.  OSHA's Salt Lake Technical Center (SLTC) laboratory reports that the sample contains 55 percent quartz.  SLTC also reports a Sampling and Analytical Error (SAE) of 0.20 for the sample.

    Step1.  Determine the jackhammer operator's 8-hour Time Weighted Average (TWA) respirable dust exposure (assuming zero exposure for the unsampled portion of the 8-hour shift):
    Step1

    Step 2. Calculate the general industry PEL, assuming the conditions for the jackhammer operator sample containing 55 percent respirable quartz:
    Step 2.

    Step 3. Calculate the Severity Ratio:
    Step 3

    Step 4. Calculate confidence limits by applying the sampling and analytical error (SAE):

          Lower Confidence Limits (LCL) = 5.4 - 0.20 = 5.2

    Step 5. Based on a severity of 5.4, the sample exceeds the 95% confidence limit for overexposure.

    Step 6. Apply the OSHA-adopted conversion factor to the jackhammer operator's exposure result from Step 1 and Reference Formula (B) above:
    Step 6

    Step 7. Calculate the applicable construction PEL, for jackhammer operator sample containing 55 percent respirable quartz:
    Step 7
    Step 8. Conclusion.  The 8-hour TWA exposure of the jackhammer operator exceeds the construction industry PEL for crystalline silica (quartz).

    Example 2: Two samples are obtained for a construction foreman overseeing a concrete drill press operation.  Both samples are collected at a flow rate of 1.7 L/min.  The duration of Sample A is 238 minutes, yielding a total sample volume of 0.40 m3.  The respirable dust collected on the filter is determined to weigh 0.855 mg, resulting in a respirable dust concentration of 2.1 mg/m3.  The SLTC laboratory reports that Sample A contains 30 percent quartz.  The duration of Sample B is 192 minutes, yielding a total sample volume of 0.326 m3.  The respirable dust weight is 0.619 mg, resulting in a concentration of 1.9 mg/m3.  The total weight of respirable dust collected on both samples is 1.474 mg.  The SLTC laboratory reports that Sample B contains 25 percent quartz.  SLTC reports an SAE of 0.16 for both samples.

    Step 1.  Determine the foreman's 8-hour TWA respirable dust exposure:
    Step 1
    Step 2. Determine average quartz content since SLTC provided two different percentages of quartz:
    Step 2
    Step 3. Calculate the general industry PEL, assuming the conditions for the construction foreman sample containing 28 percent respirable quartz:
    Step 3
    Step 4. Calculate the Severity Ratio:
    Step 4
    Step 5. Calculate confidence limits by applying the sampling and analytical error (SAE):

    LCL = 5.4 - 0.16 = 5.24

    Step 6. Based on a severity of 5.4, the sample exceeds the 95% confidence limit for overexposure.

    Step 7. Apply the OSHA-adopted conversion factor to the construction foreman's exposure result from Step 1 and Reference Formula (B) above:
    Step 7
    Step 8. Calculate the applicable construction PEL, using Reference Formula (A) above, for the foreman's samples containing an average of 28 percent respirable quartz:
    Step 8
    Step 7. Conclusion.  The 8-hour TWA exposure of the foreman exceeds the construction industry PEL for crystalline silica (quartz).





Appendix F:  Employee Questionnaire

This questionnaire, when completed, may be considered a medical record and must be used in accordance with 1913.10 - Rules Concerning OSHA Access to Employee Medical Records.  The questionnaire is intended to provide Compliance Safety and Health Officers (CSHOs) with a form they may fill out when interviewing employees to evaluate the employer's medical monitoring program. CSHOs should consult with the OSHA Office of Occupational Medicine regarding any findings of potential silicosis.

Date:   Company Name:   Location:  

A.  Personal Information

Employee's Name:       Gender:   Male   Female
Current Job Title:       Age:  

B.  Job-Related Information

Number of hours worked in silica-related tasks per week:   List previous jobs and duration of each job:
  10-20   a.   (       yrs.)
  20-30   b.   (       yrs.)
  30-40   c.   (       yrs.)
  More than 40 (                  hours)   d.   (       yrs.)

Time at current job:
  Six months or less
  1-2 yrs
  3-5 yrs
  More than 5 yrs. ( ______ yrs.)

C. Brief Medical History

Are you being treated by a physician for breathing problems?   Yes   No
Have you ever had a chest X-ray?   Yes   No
If yes, when was your last chest X-ray?  
Why was the chest X-ray taken?  
Did the doctor tell you everything was normal?   Yes   No
If no, what was noted?  
What treatment are you receiving for this problem?  
Have you discussed your medical history with your employer?   Yes   No
Are you a cigarette smoker?   Yes   No



Appendix G:  Non-Mandatory Medical Monitoring Recommendations for Employees Exposed to Crystalline Silica

  1. Recommendations for Baseline Medical Examination

    Note: These are recommendations only and are not required by any current OSHA regulation.

    It is recommended that a pre-placement baseline medical examination be provided to employees who are potentially exposed to crystalline silica at one-half the permissible exposure limit (PEL) or more.  The baseline examination should contain the following elements:

    • A medical examination emphasizing the respiratory system, as well as an occupational and medical history; and

    • A chest roentgenogram (X-ray), posteroanterior 14" x 17" or 14" x 14", classified according to the 1980 ILO International Classification of Radiographs of Pneumoconiosis (ILO, 1981), and read by a board-certified radiologist or certified class "B" reader (who is qualified to distinguish silicosis from sarcoidosis, asbestosis, coal miner's pneumoconiosis, and other pneumoconioses).

  2. Recommended Frequency of Examinations

    • It is recommended that a medical examination emphasizing the respiratory system and a chest X-ray be repeated every three years if the employee has less than 15 years of crystalline silica exposure, every two years if the employee has 15 to 20 years of exposure, and annually if the employee has 20 or more years of exposure.

    • It is recommended that a chest X-ray be obtained at termination of employment.



Appendix H:  CSHO Checklist for Conducting Silica-Related Inspections

This non-mandatory checklist is intended as a quick reference tool for Compliance Safety and Health Officers (CSHOs) conducting silica-related inspections.  The CSHO may wish to review the checklist before completing the inspection to make sure that none of the essential elements have been overlooked.  The checklist addresses all of the topics discussed in Section XI(B), Inspection Procedures, of this directive.

       Employee Exposure Monitoring        Medical Surveillance
    Sample for Respirable Dust/Silica     Employer Aware of Silicosis Risk
  Leak Test Filters/Cyclones   Employer Identifying Possible Cases
  Bulk Samples of Settled Dust   Employer Referring Cases to Physician
  Employer's Monitoring Records   Other              
  Other                  
           Housekeeping and Hygiene Practices
       Engineering and Work Practice Controls     Facility Cleanliness
    Location of Employees   Clean-up Methods (Compressed Air, Dry Sweeping?)
  Ventilation
  Wet Methods   Change Rooms/PPE Storage
  Other                 Separate Break Areas
      Other              
       Respiratory Protection    
    Written Program        Employee Exposure and Medical Records
  Cartridge Selection and Change-out Schedule     Employer Monitoring and Medical Records
  Medical and Fit Test Records   Employee Access and Confidentiality
  Breathing Air Quality and Use   Other              
  Other                  
           Abrasive Blasting (on-site or off-site)
       Hazard Communication     Sample for Silica and Metals
    Written Program   (including Bystanders)
  MSDSs   Sample for Noise
  Training   Ventilation and Dust Containment
  Bulk Samples of Products   PPE and Respirators
  Other                 Carbon Monoxide Alarm on Respirator
      Manual Control of Blast Nozzle
       Symptoms of Silicosis in Workplace   Operating Valve
    Survey/Interview Employees   Electrical Grounding
  Employees Obtaining Medical Evaluations   Pressure Range (90-120 psi)
  Other                   Heat Stress
      Other




Appendix I:  Case File Components to be Sent to the National Office
1.   OSHA 1

2.   OSHA 1A

3.   OSHA 1B/IH for overexposures to silica.

4.   Engineering Controls (including failed ones) used to control silica exposures.

See section XI. D. - Follow-up and Monitoring for additional information.





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INDEX

A

Abatement Verification
Abrasive Blasting
Alliances
Application
Assigned Protection Factor

B

Background
Bricks
Bronchitis
Bulk Samples

C

Carcinogen
Case File Submission
Cement Boards
Complaints
Compressed Air
Construction PEL
Consultation Programs
Contaminated Clothing
Conversion Factor
Coordination
Crushed Stone
CSHO Checklist
Cylcone Leak Testing

D

Deletions

E

Employee Questionnaire
Employee Records
Engineering Controls
Evaluation
Expanding Inspection Scope
Exposure Monitoring

F

Federal Agencies
Federal Program Change
Follow Up
Forms of Silica

G

Goals of NEP
GPRA

H

Hazard Communication
Health Effects of Silica
House Keeping
Hygiene Practices

I

IARC
IMIS Coding Instructions
Industrial Sources of Crystalline Silica Exposure
Industry Identification
Inspection Procedures
Inspection Scheduling

L

Lung Cancer

M

Master List
Medical Monitoring Recommendations
Minimum Respiratory Protection
MSHA

N

Non-English Speaking Groups

O

Outreach

P

Partnerships
PEL Calculations
Purpose of NEP

R

Recordkeeping
References
Referrals
Renal Disease
Resource Allocation
Respiratory Protection

S

Sampling Equipment
Sampling Instructions
Scheduling
Scleroderma
Severity Ratio
SIC Codes
Silica Sources
Silicosis
Silicosis History
Site Selection
Stomach Cancer

T

Targeting Sources/Audiences
Thoracic samples
Tuberculosis

V

Ventilation

W

Work Practice Controls


Directives - Table of Contents Directives - Table of Contents