Disclaimer: The information contained in these guidelines is intended for reference purposes only. It provides a summary of information about chemicals that workers may be exposed to in their workplaces. The information may be superseded by new developments in the field of industrial hygiene. Readers are therefore advised to regard these recomendations as general guidelines and to determine whether new information is available.

OCCUPATIONAL SAFETY AND HEALTH GUIDELINE FOR WOOD DUST, ALL SOFT AND HARDWOODS, EXCEPT WESTERN RED CEDAR

INTRODUCTION

This guideline summarizes pertinent information about wood dust, all soft and hardwoods, except western red cedar for workers and employers as well as for physicians, industrial hygienists, and other occupational safety and health professionals who may need such information to conduct effective occupational safety and health programs. Recommendations may be superseded by new developments in these fields; readers are therefore advised to regard these recommendations as general guidelines and to determine whether new information is available.

SUBSTANCE IDENTIFICATION

* Formula

Not applicable.

* Structure

(For Structure, see paper copy)

* Synonyms

Finely divided wood particles, powdered wood, sawdust, wood flour, hardwood dust, wood shavings, softwood dust, wood dust

* Identifiers

1. CAS No.: Data not available.

2. RTECS No.: ZC9850000

3. Specific DOT number: None

4. Specific DOT label: None

* Appearance and odor

This type of wood dust consists of the dust from all hard and soft woods with the exception of western red cedar. It is pulverized wood wastes, or the dusts from cutting, shaping, drilling, sanding, or general handling of wood.

CHEMICAL AND PHYSICAL PROPERTIES

* Physical data

1. Molecular weight: Not applicable.

2. Boiling point: Not applicable.

3. Specific gravity: Not applicable.

4. Vapor density: Not applicable.

5. Melting point: Not applicable.

6. Vapor pressure: Not applicable.

7. Solubility: Not applicable.

8. Evaporation rate: Not applicable.

* Reactivity

1. Conditions contributing to instability: Heat, sparks or open flames.

2. Incompatibilities: None reported.

3. Hazardous decomposition products: None reported.

4. Special precautions: A severe explosion hazard may exist if a wood dust cloud comes into contact with a source of ignition. Partially burned or scorched wood dust is especially hazardous if dispersed in air because of its explosivity.

* Flammability

The National Fire Protection Association has not assigned a flammability rating to these wood dusts. Other sources rate wood dust as a combustible solid when this substance is exposed to heat or open flame.

1. Flash point: Not applicable.

2. Autoignition temperature: Data not available.

3. Flammable limits in air: Data not available.

4. Extinguishant: Use an extinguishant that is suitable for the materials involved in the surrounding fire.

Fires involving wood dust should be fought upwind from the maximum distance possible. Isolate the hazard area and deny access to unnecessary personnel. Firefighters should wear a full set of protective clothing and self-contained breathing apparatus when fighting fires involving wood dust, all soft and hardwoods, except western red cedar.

EXPOSURE LIMITS

* OSHA PEL

The Occupational Safety and Health Administration (OSHA) has established a permissible exposure limit (PEL) of 15 milligrams per cubic meter (mg/m(3)) of air for the total dust and 5 mg/m(3) for the respirable fraction of wood dust, all soft and hardwoods, except western red cedar (as a nuisance dust) [29 CFR 1910. 1000, Table Z-3].

* NIOSH REL

The National Institute for Occupational Safety and Health (NIOSH) has established a recommended exposure limit (REL) for wood dust, all soft and hardwoods, except western red cedar of 1 mg/m(3) as a TWA for up to a 10-hour workday and a 40-hour workweek [NIOSH 1992].

* ACGIH TLV

The American Conference of Governmental Industrial Hygienists (ACGIH) has assigned wood dust, all soft and hardwoods, except western red cedar a threshold limit value (TLV) of 1 mg/m(3) for certain hardwoods, such as beech and oak, and 5 mg/m(3) for soft wood, as TWAs for a normal 8-hour workday and a 40-hour workweek and a short-term exposure limit (STEL) of 10 mg/m(3) for soft wood, for periods not to exceed 15 minutes. Exposures at the STEL concentration should not be repeated more than four times a day and should be separated by intervals of at least 60 minutes [ACGIH 1994, p. 36].

* Rationale for Limits

The NIOSH limit is based on the risk of pulmonary dysfunction and respiratory effects [NIOSH 1992].

The ACGIH limits are based on the risk of impaired nasal mucociliary function, potential nasal adenocarcinoma, and related hyperplasias (1 mg/m(3) TWA for hardwoods), and dermatitis and upper respiratory tract disease (for softwoods) [ACGIH 1991, pp. 1729-1730].

HEALTH HAZARD INFORMATION

* Routes of Exposure

Exposure to wood dust can occur through inhalation, and eye or skin contact.

* Summary of toxicology

1. Effects on Animals: There is limited data available on the toxicology of wood dusts in animals. A methanol extract of beech wood dust was mutagenic in the Ames assay in the presence of an exogenous metabolic system [IARC 1987]. Among hamsters exposed by inhalation to fine particles of beech wood dust, one animal out of 22 had a nasal tumor [IARC 1987]. IARC concluded that there is inadequate evidence for the carcinogenicity of wood dust to experimental animals [IARC 1987].

2. Effects on Humans: Exposure to wood dusts can result in eye and skin irritation, dermatitis, respiratory system effects (including hypersensitivity, asthma, suberosis, granulomatous pneumonitis, or acute airway obstruction), and cancer in humans. Exposure to wood dust can result in the development of contact dermatitis [ACGIH 1991]. The primary irritant dermatitis resulting from skin contact with wood dusts consist of erythema, blistering, and sometimes erosion and secondary infections occur [Hathaway et al. 1991]. The irritant chemicals are normally found in the outer part of the wood in the sap or bark, and therefore, loggers and other workers involved in the initial handling of the wood experience dermatitis. The allergic dermatitis typically results in redness, scaling, and itching, which may become vesicular dermatitis if exposures are repeated [Hathaway et al. 1991]. This type of dermatitis often occurs on the hands, face, forearms, eyelids, neck, and genitals, and will sometimes not appear until several years have passed following the exposure, although frequently the signs are apparent within a few days or weeks [Hathaway et al. 1991]. The chemicals causing this effect are generally found in the heartwood, and therefore those workers involved in secondary wood processing are affected (e.g. carpenters, furniture makers, etc.). Certain wood dust (primarily african woods, and cork) are also associated with asthma [ACGIH 1991]. Acute and chronic respiratory system reactions to exposure can include chronic bronchitis, or chronic airflow limitation associated with asthma [Rom 1992]. An increased risk of nasal tumors (primarily adenocarcinomas) is associated with exposure to wood dust; IARC has concluded that there is sufficient evidence for the carcinogenicity of furniture and cabinet making to humans, there is limited evidence for the carcinogenicity of carpentry and joinery, and there is inadequate evidence for the carcinogenicity of lumber and sawmill industries and pulp and paper manufacturing [IARC 1987]. Hard wood dust appears to be the primary substance of concern, although the carcinogenic substances in hardwood are unknown [IARC 1987].

* Signs and symptoms of exposure

1. Acute exposure: Acute exposure to wood dusts can result in eye and skin irritation, asthma, erythema, blistering, erosion and secondary infections of the skin, redness, scaling, itching, and vesicular dermatitis.

2. Chronic exposure: Chronic exposure to wood dusts can result in dermatitis reactions, asthma, pneumonitis, and coughing, wheezing, fever and the other signs and symptoms associated with chronic bronchitis. Chronic exposure may also result in nasal cancer.

EMERGENCY MEDICAL PROCEDURES

* Emergency medical procedures: [NIOSH to supply]

5. Rescue: Remove an incapacitated worker from further exposure and implement appropriate emergency procedures (e.g., those listed on the Material Safety Data Sheet required by OSHA's Hazard Communication Standard [29 CFR 1910.1200]). All workers should be familiar with emergency procedures, the location and proper use of emergency equipment, and methods of protecting themselves during rescue operations.

EXPOSURE SOURCES AND CONTROL METHODS

The following operations may involve wood dust and lead to worker exposures to these dusts:

• The logging and transportation of wood
• The handling or initial processing of raw wood into usable lumber
• The secondary handling of wood for the production of various wood products

Methods that are effective in controlling worker exposures to wood dust, all soft and hardwoods, except western red cedar, depending on the feasibility of implementation, are as follows:

• Process enclosure
• Local exhaust ventilation
• General dilution ventilation
• Personal protective equipment

Workers responding to a release or potential release of a hazardous substance must be protected as required by paragraph (q) of OSHA's Hazardous Waste Operations and Emergency Response Standard [29 CFR 1910.120].

Good sources of information about control methods are as follows:

1. ACGIH [1992]. Industrial ventilation--a manual of recommended practice. 21st ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists.

2. Burton DJ [1986]. Industrial ventilation--a self study companion. Cincinnati, OH: American Conference of Governmental Industrial Hygienists.

3. Alden JL, Kane JM [1982]. Design of industrial ventilation systems. New York, NY: Industrial Press, Inc.

4. Wadden RA, Scheff PA [1987]. Engineering design for control of workplace hazards. New York, NY: McGraw-Hill.

5. Plog BA [1988]. Fundamentals of industrial hygiene. Chicago, IL: National Safety Council.

MEDICAL SURVEILLANCE

OSHA is currently developing requirements for medical surveillance. When these requirements are promulgated, readers should refer to them for additional information and to determine whether employers whose employees are exposed to wood dust, all soft and hardwoods, except western red cedar are required to implement medical surveillance procedures.

* Medical Screening

Workers who may be exposed to chemical hazards should be monitored in a systematic program of medical surveillance that is intended to prevent occupational injury and disease. The program should include education of employers and workers about work-related hazards, early detection of adverse health effects, and referral of workers for diagnosis and treatment. The occurrence of disease or other work-related adverse health effects should prompt immediate evaluation of primary preventive measures (e.g., industrial hygiene monitoring, engineering controls, and personal protective equipment). A medical surveillance program is intended to supplement, not replace, such measures. To detect and control work-related health effects, medical evaluations should be performed (1) before job placement, (2) periodically during the term of employment, and (3) at the time of job transfer or termination.

* Preplacement medical evaluation

Before a worker is placed in a job with a potential for exposure to wood dust, a licensed health care professional should evaluate and document the worker's baseline health status with thorough medical, environmental, and occupational histories, a physical examination, and physiologic and laboratory tests appropriate for the anticipated occupational risks. These should concentrate on the function and integrity of the skin and respiratory system. Medical surveillance for respiratory disease should be conducted using the principles and methods recommended by the American Thoracic Society.

A preplacement medical evaluation is recommended to assess medical conditions that may be aggravated or may result in increased risk when a worker is exposed to wood dust at or below the prescribed exposure limit. The health care professional should consider the probable frequency, intensity, and duration of exposure as well as the nature and degree of any applicable medical condition. Such conditions (which should not be regarded as absolute contraindications to job placement) include a history and other findings consistent with diseases of the skin or respiratory system.

* Periodic medical evaluations

Occupational health interviews and physical examinations should be performed at regular intervals during the employment period, as mandated by any applicable Federal, State, or local standard. Where no standard exists and the hazard is minimal, evaluations should be conducted every 3 to 5 years or as frequently as recommended by an experienced occupational health physician. Additional examinations may be necessary if a worker develops symptoms attributable to wood dust exposure. The interviews, examinations, and medical screening tests should focus on identifying the adverse effects of wood dust on the skin or respiratory system. Current health status should be compared with the baseline health status of the individual worker or with expected values for a suitable reference population.

* Termination medical evaluations

The medical, environmental, and occupational history interviews, the physical examination, and selected physiologic or laboratory tests that were conducted at the time of placement should be repeated at the time of job transfer or termination to determine the worker's medical status at the end of his or her employment. Any changes in the worker's health status should be compared with those expected for a suitable reference population. Because occupational exposure to wood dust may cause diseases with prolonged latent periods, the need for medical surveillance may extend well beyond the termination of employment.

* Biological monitoring

Biological monitoring involves sampling and analyzing body tissues or fluids to provide an index of exposure to a toxic substance or metabolite. No biological monitoring test acceptable for routine use has yet been developed for wood dust.

WORKPLACE MONITORING AND MEASUREMENT

Determination of a worker's exposure to airborne wood dust is made using a tared low ash polyvinyl chloride filter (5 microns) preceded for respirable fraction sampling by a 10 mm nylon cyclone. Samples are collected at a maximum flow rate of 1.7 liters/minute (respirable fraction) or 2.0 liters/minute (total dust) until a maximum collection volume of 816 liters (respirable fraction) or 960 liters (total dust) is reached. Analysis is conducted by gravimetric methods. This method (for nuisance dusts) is described in the OSHA Computerized Information System [OSHA 1994] and is fully validated. NIOSH has published a similar methods (Method No. 0500 and 0600) for the sampling and analysis of nuisance dusts [NIOSH 1994b].

PERSONAL HYGIENE PROCEDURES

If wood dust contacts the skin, workers should wash the affected areas with soap and water.

Clothing contaminated with wood dust should be removed, and provisions should be made for the safe removal of the chemical from the clothing. Persons laundering the clothes should be informed of the hazardous properties of wood dust.

A worker who handles wood dust should thoroughly wash hands, forearms, and face with soap and water before eating, using tobacco products, using toilet facilities, applying cosmetics, or taking medication.

Workers should not eat, drink, use tobacco products, apply cosmetics, or take medication in areas where wood dust is handled, or processed.

STORAGE

Wood dust should be stored in a cool, dry, well-ventilated area in tightly sealed containers that are labeled in accordance with OSHA's Hazard Communication Standard [29 CFR 1910.1200]. Containers of wood dust should be protected from physical damage and stored separately from all sources of ignition.

SPECIAL REQUIREMENTS

U.S. Environmental Protection Agency (EPA) requirements for emergency planning, reportable quantities of hazardous releases, community right-to-know, and hazardous waste management may change over time. Users are therefore advised to determine periodically whether new information is available.

* Emergency planning requirements

Wood dust is not subject to EPA emergency planning requirements under the Superfund Amendments and Reauthorization Act (SARA) (Title III) in 42 USC 11022.

* Reportable quantity requirements for hazardous releases

A hazardous substance release is defined by EPA as any spilling, leaking, pumping, pouring, emitting, emptying, discharging, injecting, escaping, leaching, dumping, or disposing into the environment (including the abandonment or discarding of contaminated containers) of hazardous substances. In the event of a release that is above the reportable quantity for that chemical, employers are required to notify the proper Federal, State, and local authorities [40 CFR 355.40].

Employers are not required by the emergency release notification provisions in 40 CFR Part 355.40 to notify the National Response Center of an accidental release of wood dust; there is no reportable quantity for these substances.

* Community right-to-know requirements

Employers are not required by EPA in 40 CFR Part 372.30 to submit a Toxic Chemical Release Inventory form (Form R) to EPA reporting the amount of wood dust emitted or released from their facility annually.

* Hazardous waste management requirements

EPA considers a waste to be hazardous if it exhibits any of the following characteristics: ignitability, corrosivity, reactivity, or toxicity as defined in 40 CFR 261.21-261.24. Under the Resource Conservation and Recovery Act (RCRA) [40 USC 6901 et seq.], EPA has specifically listed many chemical wastes as hazardous. Although wood dust is not specifically listed as a hazardous waste under RCRA, EPA requires employers to treat waste as hazardous if it exhibits any of the characteristics discussed above.

Providing detailed information about the removal and disposal of specific chemicals is beyond the scope of this guideline. The U.S. Department of Transportation, EPA, and State and local regulations should be followed to ensure that removal, transport, and disposal of this substance are conducted in accordance with existing regulations. To be certain that chemical waste disposal meets EPA regulatory requirements, employers should address any questions to the RCRA hotline at (703) 412-9810 (in the Washington, D.C. area) or toll-free at (800) 424-9346 (outside Washington, D.C.). In addition, relevant State and local authorities should be contacted for information on any requirements they may have for the waste removal and disposal of this substance.

RESPIRATORY PROTECTION

* Conditions for respirator use

Good industrial hygiene practice requires that engineering controls be used where feasible to reduce workplace concentrations of hazardous materials to the prescribed exposure limit. However, some situations may require the use of respirators to control exposure. Respirators must be worn if the ambient concentration of wood dust exceeds prescribed exposure limits. Respirators may be used (1) before engineering controls have been installed, (2) during work operations such as maintenance or repair activities that involve unknown exposures, (3) during operations that require entry into tanks or closed vessels, and (4) during emergencies. Workers should only use respirators that have been approved by NIOSH and the Mine Safety and Health Administration (MSHA).

* Respiratory protection program

Employers should institute a complete respiratory protection program that, at a minimum, complies with the requirements of OSHA's Respiratory Protection Standard [29 CFR 1910.134]. Such a program must include respirator selection, an evaluation of the worker's ability to perform the work while wearing a respirator, the regular training of personnel, respirator fit testing, periodic workplace monitoring, and regular respirator maintenance, inspection, and cleaning. The implementation of an adequate respiratory protection program (including selection of the correct respirator) requires that a knowledgeable person be in charge of the program and that the program be evaluated regularly. For additional information on the selection and use of respirators and on the medical screening of respirator users, consult the latest edition of the NIOSH Respirator Decision Logic [NIOSH 1987b] and the NIOSH Guide to Industrial Respiratory Protection [NIOSH 1987a].

PERSONAL PROTECTIVE EQUIPMENT

Workers should use appropriate personal protective clothing and equipment that must be carefully selected, used, and maintained to be effective in preventing skin contact with wood dust. The selection of the appropriate personal protective equipment (PPE) (e.g., gloves, sleeves, encapsulating suits) should be based on the extent of the worker's potential exposure to wood dust.

To evaluate the use of PPE materials with wood dust, users should consult the best available performance data and manufacturers' recommendations. Significant differences have been demonstrated in the chemical resistance of generically similar PPE materials (e.g., butyl) produced by different manufacturers. In addition, the chemical resistance of a mixture may be significantly different from that of any of its neat components.

Any chemical-resistant clothing that is used should be periodically evaluated to determine its effectiveness in preventing dermal contact. Safety showers and eye wash stations should be located close to operations that involve wood dust.

Splash-proof chemical safety goggles or face shields (20 to 30 cm long, minimum) should be worn during any operation in which a solvent, caustic, or other toxic substance may be splashed into the eyes.

In addition to the possible need for wearing protective outer apparel (e.g., aprons, encapsulating suits), workers should wear work uniforms, coveralls, or similar full-body coverings that are laundered each day. Employers should provide lockers or other closed areas to store work and street clothing separately. Employers should collect work clothing at the end of each work shift and provide for its laundering. Laundry personnel should be informed about the potential hazards of handling contaminated clothing and instructed about measures to minimize their health risk.

Protective clothing should be kept free of oil and grease and should be inspected and maintained regularly to preserve its effectiveness.

Protective clothing may interfere with the body's heat dissipation, especially during hot weather or during work in hot or poorly ventilated work environments.

REFERENCES

ACGIH [1991]. Documentation of the threshold limit values and biological exposure indices. 6th ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists.

ACGIH [1994]. 1994-1995 Threshold limit values for chemical substances and physical agents and biological exposure indices. Cincinnati, OH: American Conference of Governmental Industrial Hygienists.

ATS [1987]. Standardization of spirometry -- 1987 update. American Thoracic Society. Am Rev Respir Dis 136:1285-1296.

CFR. Code of Federal regulations. Washington, DC: U.S. Government Printing Office, Office of the Federal Register.

Genium [1993]. Material safety data sheet No. 376. Schenectady, NY: Genium Publishing Corporation.

Hathaway GJ, Proctor NH, Hughes JP, and Fischman ML [1991]. Proctor and Hughes' chemical hazards of the workplace. 3rd ed. New York, NY: Van Nostrand Reinhold.

IARC [1987]. IARC monographs on the evaluation of carcinogenic risk of chemicals to man. Supplement 7. Lyon, France: World Health Organization, International Agency for Research on Cancer.

Lewis RJ, ed. [1993]. Hawley's condensed chemical dictionary. 12th ed. New York, NY: Van Nostrand Reinhold Company.

Mickelsen RL, Hall RC [1987]. A breakthrough time comparison of nitrile and neoprene glove materials produced by different glove manufacturers. Am Ind Hyg Assoc J 48(11): 941-947.

Mickelsen RL, Hall RC, Chern RT, Myers JR [1991]. Evaluation of a simple weight-loss method for determining the permeation of organic liquids through rubber films. Am Ind Hyg Assoc J 52(10): 445-447.

NIOSH [1987a]. NIOSH guide to industrial respiratory protection. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 87-116.

NIOSH [1987b]. NIOSH respirator decision logic. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 87-108.

NIOSH [1989]. Registry of toxic effects of chemical substances: Wood dust. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, Division of Standards Development and Technology Transfer, Technical Information Branch.

NIOSH [1992]. Recommendations for occupational safety and health: Compendium of policy documents and statements. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 92-100.

NIOSH [1994a]. NIOSH pocket guide to chemical hazards. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 94-116.

NIOSH [1994b]. NIOSH manual of analytical methods. 4th ed. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 94-113.

OSHA [1994]. Computerized information system. Washington, DC: U.S. Department of Labor, Occupational Safety and Health Administration.

Rom WN [1992]. Environmental and occupational medicine. 2nd ed. Boston, MA: Little, Brown and Company.

USC. United States code. Washington. DC: U.S. Government Printing Office.