SUMMARY OF STAKEHOLDER COMMENTS
SAN FRANCISCO, CA.
JUNE 30, 1999
Issue 1: Scope
One stakeholder stated that silica exposures occur in the following activities in the demolition industry:
- Saw cutting,
- Removal of walls,
- Excavating, and
- Waste handling (such as dumping silicacious materials in trucks or dumpsters).
This stakeholder noted that interior demolition is the most hazardous with respect to silica exposures because jack-hammering and pulverizing cause exposures up to 3 times the current PEL. These activities occur on both renovation projects and demolition projects.
A stakeholder stated that silica exposures occur in glass making operations because the raw materials in this industry are 70 percent silica sand. Operations where exposures occur are:
- Surface mining
- Materials handling, and
- Delivery of the sand to the melting furnace.
Other operations in the glass industry where silica exposures occur include:
- Utility work,
- Manual mixing,
- Servicing systems (particularly dust collection systems).
A stakeholder from the brick, marble and masonry industry stated that silica exposures occur during dry cutting of materials and that a trend is developing toward the use of dry saws (quickie saw cuts) because it takes more time to set up a water supply. Dry cutting is also used for elevated work (scaffolds, upper floors, etc.) because it is inefficient to move the work down to the ground to reach a saw that is equipped with water. For these two reasons, dry cutting costs less. This stakeholder stated that dry cutting also is used for cutting granite, terrazzo, marble and brick. These operations often take place in contained areas with workers using only paper dust masks and with no monitoring. He stated that such situations occur on every job.
A stakeholder from the demolition industry stated that dry cutting is not a common practice in his industry and that saws are always used wet.
Another stakeholder noted that silica is a component in most refractory brick. Silica exposures occur during cutting, which is performed wet 90-95 percent of the time according to this stakeholders. Some situations in refractory brick installation must be performed dry. Brick for furnaces that operate at very high temperatures (1,300oF or above) must be kept dry during installation and therefore cannot be cut wet. Silica exposures also occur in refractory brick operations when furnaces are demolished and relined and during pouring and forming gunnite in a refractory furnace.
Silica exposures can occur in tunneling operations during dry core drilling and, to a lesser extent, during drilling and blasting operations. Silica exposures can also result from road and housekeeping activities. Conveyor belts also generate dust. Silica-containing dusts are not always easily visible. This stakeholder noted that a little "haze" in the air is a common problem, and that this factor is a key element in worker training. He stated that silica exposures are difficult to identify without air sampling and industrial hygiene monitoring.
A stakeholder representing the industrial sand industry stated that silica exposures can occur in the following operations:
- Packaging, and
- Bulk loading.
The operations that occur dry generally have higher silica exposures and are more difficult to control than these performed wet.
When asked by OSHA to address exposures during housekeeping operations, a stakeholder from the glass manufacturing industry stated that wet sweeping and vacuuming are used instead of dry sweeping and that the use of high pressure air hoses has been prohibited. He further stated that worker training that addressed housekeeping practices had been instituted. Another stakeholder stated that replacing brooms with vacuums equipped with HEPA filters, washing down equipment frequently, and proper work practices when shoveling debris have been effective.
A stakeholder that uses gunnite for concrete restoration stated that silica is present in all phases of the operation. Refractory gunnite is used in confined spaces with exhaust fans that tend to spread the dust to other areas of the job. He further stated that all employees are trained annually and that all new employees receive ½ day initial training.
A stakeholder from the glass manufacturing industry noted that, by its very nature, silica is abrasive and that as a result, leaks in equipment occur frequently and must be responded to immediately. Prevent maintenance (such as replacing seals and components that wear out quickly) is important in minimizing leaks caused by silica's abrasive nature.
One stakeholder addressed the issue of newly fractured silica particles and stated that OSHA must present substantial evidence of a difference in risk for this type of silica should the agency decide to make a distinction in the rule.
A stakeholder from the industrial sand industry also addressed OSHA's questions about exposures during housekeeping. He stated that frequently washing down facilities and equipment to floor drains and proper design of facilities were important. Further, he stated that dry sweeping had been prohibited and that brushes and brooms were no longer used. HEPA vacuums were used to remove dust from clothing or tyvek suits. Aerosol monitors were used for real-time monitoring of dusty areas in conjunction with employee exposure monitoring for silica exposures.
A stakeholder representing the foundry industry stated that silica exposure is possible during sand mold making and de-casting. He further noted that the sand is broken down in the foundry process. Dust collectors are used in these operations. In large foundries nearly continual clean-up is performed by manual sweepers. He further noted that resins mixed with the sand tend to reduce exposures. Addressing small foundries, he said that while the process is similar, they cannot dedicate personnel to continual clean-up the way a larger foundry can.
A stakeholder from the stone quarry industry stated that the standard should only be applicable to materials that contain more than 1 or 2 percent quartz. He stated that materials that are less than 1 percent quartz cannot mathematically exceed the NIOSH REL, which is lower than OSHA's current PEL. The finely ground marble his firm produces is less than 1 percent quartz, and the dust particle size is tightly controlled and typically non-respirable. While his operations are not regulated by OSHA, he noted that his customers are included in the scope of the standard and do not control particle size as effectively as his firm does.
A stakeholder from the crushed stone industry confirmed that invisible dust is a concern and that current monitoring techniques take too long to yield results. He perceived a need for real-time monitoring with instantaneous read-out.
A stakeholder from the construction industry believed that sandblasting was the only real concern in construction. Using sand during turf maintenance and stadium work to aid drainage was not an exposure problem.
A representative from the foundry industry stated that the industry trade association has an engineering group performing testing in about 30 foundries to determine which situations cause employee exposures. He noted that they were having difficulty measuring as low as 0.05 mg/m3 [as an 8-hr time weighted average]..
A stakeholder noted that many different exposures occur in demolition operations and that some analogy to lead and asbestos is appropriate. Thus, decontamination procedures, wet methods, and protective clothing provide protection that reduces the need for immediate read-out of monitoring results.
A stakeholder representing a state regulatory agency questioned whether agriculture should be excluded from the standard. He stated that it helps when OSHA explains its rationale for including some industries while excluding others and that excluding some industries leads to some logistical problems for the state programs.
A stakeholder representing the medical community stated that sandblasting must be addressed and recommended that a short-term ceiling limit be used because this approach fits the exposure pattern for many operations. He also expressed concern for environmental exposure and exposure of family members due to "take home" exposure. Responding to question, he could not provide references or a source for any measurement of take-home exposure.
Another stakeholder urged that the use of sand for sandblasting be restricted, since substitutes are available.
A stakeholder noted that job specifications for construction of prisons and schools do not allow the wet cutting of bricks due to concern that the bonding of the mortar may be affected.
Issue 2: Controlling Exposure
Controls used in tunneling operations are primarily point source controls, such as local exhaust systems with scrubbers and HEPA filter banks. Conveyors are a difficult source to control using water sprays because the dust tends to stick to the conveyor. Fogging with water has been tried, but it is important not to get the conveyor belt wet. A conveyor belt scrubber is also used to remove the fine dust from the surface of the belt.
A stakeholder expressed the need for substitutes for silica in abrasive blasting operations. This stakeholder supported OSHA's hierarchy of controls and suggested more specific requirements for the use of respirators.
A stakeholder from the medical community also expressed support for the hierarchy of controls, preferring engineering and work practice controls to personal protective equipment. He further recommended that appropriate medical screening, fit testing and training for the use of respirators, including procedures for cleaning and maintenance be included in the standard.
Typical jobs in refractory removal and installation last only a few weeks. The stakeholder from this industry stated that the use of engineering controls is not feasible for such short duration jobs. He further stated that enclosing the mixing stations increases exposure to the directly affected worker(s) but reduces exposure to other workers on the site. As a result, employee training and the use of respirators are critical. Monitoring data collected over the last 5 years around mixing stations show that exposures beyond 5 feet do not exceed the current PEL for materials that contain 1-15 percent silica. This stakeholder also expressed support for a separate standard for construction operations.
Grinding operations during demolition have exposures 2-3 times the current PEL. Perimeter monitoring 10-15 feet from this operation indicates no silica exposure. Controls being used include wet methods, vacuuming clothing with HEPA vacuums, and respiratory protection. The stakeholder stated that OSHA's respirator standards are good rules that should be enforced more vigorously.
A stakeholder stated that in foundries, engineering controls such as bag houses and dust collectors are effective. However, exposures from both horizontal and vertical conveyors are difficult to control. He further stated that some of the respirable dust exposures are from natural sources and not from the sand used for mold making, which is 100 percent recycled. He expressed concern about the use of disposable respirators and stated that they should only be used for short periods of time. Only respirators with exhalation valves should be used for full-shift exposures.
A stakeholder noted the there is no substitute for sand in glass manufacturing. Drop chute covers (boots) have been used to control dust while unloading railcars. Dust collection systems are also in use. He stated that the use of personal protective equipment is critical for maintenance activities. He expressed the opinion that exposure monitoring should be used to verify that a problem does not exist.
Local exhaust ventilation was identified as the primary control method in the industrial sand industry. He noted that poor design and installation is common and can limit its effectiveness and that maintenance of ventilation equipment is a continual problem. Also, workplace noise increases with the use of ventilation systems. He stated that respirators are an adjunct control measure. This stakeholder further asserted that the most important control measure is commitment by employers, employees and government agencies. He stated that, in his firm, a report of dust exposures is sent to the board of directors and that dust control measures have reduced workers' compensation costs. In addition, his firm established a dust committee in which workers' have input into the placement of control measures and can stop the production line when high exposures occur. An aerosol monitoring instrument is used weekly and is perceived to be an effective leak detection device. In addition, water sprays can be effective in capturing respirable dust but only if atomized to generate a very fine mist.
Several stakeholders noted that OSHA prohibiting the use of dry sweeping and pressurized air for removing dust would help management enforce good work practices.
A stakeholder stated that the cost of substitutes for sand in foundries is 5-6 times more than the cost of sand.
Issue 3: Monitoring and Sampling
One stakeholder suggested a monitoring strategy that included the following:
- For 20 or fewer employees, 50 percent of employees should be sampled.
- For establishments with more than 20 employees, 10 workers plus 25 percent of
employees in excess of 20 should be sampled.
- Sampling should be conducted annually when exposures are less than 50 percent of the
- Sampling should be conducted every 6 months when exposures are in the range of 50 -100
percent of the PEL.
- Sampling should be conducted quarterly when exposures exceed the PEL.
- Sampling should be performed again when there is a change in operations.
A stakeholder representing an analytical laboratory noted that the results of the Proficiently Analytical Testing (PAT) indicated a large variability (greater the 16 percent). These data indicate that two laboratories could analyze the same sample and give acceptable results ranging from 52 to 163 ug/m3. This stakeholder stated that an analytical method must be developed to reduce this variability.
A stakeholder representing quarries stated that his firm uses real-time environmental monitors to measure ambient dust levels. He noted that there was much variability in the measurements from day to day. Loaders are equipment with environmentally controlled cabs. However, he noted that the fan in the cab tended to keep fugitive dust in the cab airborne.
A representative of the refractory industry stated that his industry had set up a consortium of firms to select one industrial hygiene consulting group. The group set up criteria for the industrial hygiene work, and receive data from the industrial hygiene consultant. Turnaround time for samples is 3 to 5 days. The industrial hygiene consultant also provides a review of new processes. A data base of employee exposures during refractory work is being developed.
A state regulatory agency reported a requirement for monitoring all substances including silica that can reasonably be expected to exceed the PEL. The agency's standard includes a requirement that monitoring be overseen by a competent person.
A stakeholder representing a labor union for the construction trades urged that OSHA include monitoring requirements in the standard and cited an example of a lengthy (2 year duration) project where no monitoring was performed.
A stakeholder representing the tunneling industry related the use of a DataRAM (aerosol monitor) to get real-time monitoring data. He noted that extensive calibration of the equipment using side-by-side sampling with x-ray diffraction (XRD) monitoring was necessary to make the data generated by such equipment meaningful. He noted that every job is started using respirators and their use is discontinued only after an action level of 50 percent of the PEL is achieved. The analytical cost for XRD analysis of $40 per sample. The total cost of each sample (including labor, supplies, etc.) Is $300-$350. The analytical fee for 24-hour turnaround is $700.
A stakeholder from the construction industry noted that monitoring is difficult for many construction projects that are of short duration. The use of representative monitoring, historical data and objective data is essential for this industry. OSHA should clarify that data collected by the general contractor on previous jobs is acceptable.
A glass industry representative conducts XRD-based monitoring and analysis by an AIHA accredited laboratory. Because glass manufacturing occurs at fixed locations, immediate feedback is not needed. The stakeholder stated that OSHA must allow the use of historical data for initial assessments and must allow a competent person to conduct exposure monitoring. Requiring a certified industrial hygienist to perform monitoring will be a burden on business, especially small businesses.
Monitoring in an industrial sand supplier's facilities is conducted by an employee(s) at the site. The use of consultants is limited. Safety and health professionals usually interpret the data generated on-site.
The stakeholder from the tunneling industry stated that monitoring by certified industrial hygienists is not common. Monitoring is typically not performed for short-term operations. There is a need to get the tunneling industry more involved in the regulatory process.
Issue 4: Screening and Surveillance
A stakeholder representing the tunneling industry stated that his firm conducts pre-placement medical screening physicals that include pulmonary function tests (PFT) and chest x-rays read by a (NIOSH accredited) B reader. Periodic medicals include PFTs annually and chest X-rays every 3-5 years or when a change in the PFT is detected. Physicians are informed of exposure levels. A medical examination is given upon termination of employment and includes a chest x-ray and other tests deemed appropriate by the physician. Of 150 employees initially screened, few employees with anomalies were seen. These cases are followed up by a physician. This stakeholder recommended that OSHA investigate any relationship between silica exposure-related health effects and smoking.
A stakeholder representing a public health organization stated that no good screening method was currently available. Termination x-rays could be misleading since silicosis can occur many years after a worker leaves employment. While not a good indicator of silicosis, the PFT may be helpful because it may detect bronchitis caused by silica exposure and is an inexpensive test. In addition, testing for tuberculosis should be included in the standard since silicosis and TB are related. This stakeholder expressed concern about the cumulative risk of exposure to repeated x-rays, which are also expensive and not helpful. Employee questionnaires were viewed as a helpful tool.
A stakeholder representing the medical community urged that medical surveillance be included in the standard because is critical to early detection of disease. He stated that medical surveillance is the final form of monitoring; it is the last method to back-stop failures of engineering controls, monitoring, etc. Medical surveillance should be designed and supervised by a physician (MD/ DO). OSHA should require that the occupational physician be provided with employee exposure monitoring data. The content of the physical should be:
- Respiratory questionnaire;
- Chest x-ray (Oce every three years was recommended but concern was expressed that this
frequency may be too long since acute and accelerated silicosis may occur more quickly.
He suggested that OSHA might tie the frequency of x-rays to exposure levels or to
specific industries or operations.);
- General physical examination (ears, eyes, nose, throat, heart, lung); and
- Pulmonary function test (annual).
The follow-up testing should be specified because many times a different physician performs the medical surveillance each year and no one looks at the long-term picture. A termination physical should be mandatory. It is the final look at a person and provides an opportunity to educate an employee on the long-term risks and actions that can be taken to reduce those risks. Both stakeholders representing the medical community agreed that B readers should be required. One stated that, in the event that there are not enough B readers, a competent person requirement should be used.
A stakeholder representing the refractory industry stated that his firm provides the medical testing required under the respirator standard. However, he cautioned that the labor pool for his industry is a large group of people that move from employer to employer. An employee may have up to 50 employers in the course of a year and potentially would receive that many x-rays. A small to medium size company may have 1,500 different employees on the payroll over the course of a year. A typical project may have 100 people at all times, but to maintain this complement as many as 250 employees may work on the project during the year. The portability of medical records is a critical issue.
A stakeholder from the foundry industry noted that the medical surveillance requirement is a "big opening " for workers compensation claims and suggested that employees should be given pre-hire medical examinations because after they are hired it is too late to screen them out. OSHA should not preclude advancing technology such as computerized reading of x-rays films.
A stakeholder from the glass manufacturing industry stated that all employees receive mandatory medical surveillance and that B readers read annual x-rays. He noted that medical surveillance is beneficial in that it can detect other diseases. Employees hate the questionnaires and are afraid the data will be used against them. Employees tend not to believe that medical information will be kept confidential. Termination examinations are difficult because employees just leave and do not stop to take a medical examination.
Employees in the industrial sand industry receive the following medical screening:
- Medical questionnaire;
- Occupational history;
- Chest x-ray (read by B reader or certified radiologist; many films are read by three
- Smoking history;
- Pulmonary function tests (optional); and
- TB skin tests for new hires.
Termination screening is not performed. This stakeholder suggested that employee participation in the medical surveillance program be a prerequisite for receiving workers' compensation benefits. Employees that show early signs of silica-related disease receive follow-up medical testing and are removed to jobs with no silica exposure. X-rays are the most sensitive method to show silica related abnormalities. No medical surveillance requirements designed to detect early silicosis are appropriate because this disease is caused by very high exposures (30 times the current PEL). This stakeholder suggested that any employer with such poor control of exposure levels is also not likely to be performing medical surveillance. He suggested that the term "screening" is not appropriate and that OSHA should use the term "medical surveillance."
Stakeholders made the following suggestions and comments:
- Silica is not the only hazard in most workplaces. To be most cost effective, OSHA should
be conscious of how the silica standard relates to other standards.
- OSHA should focus on the problem areas - The SEP data indicated 30-50 percent of
exposures exceed the current PEL. The ancillary provisions in a 6(b) rulemaking will do a
lot of good, but attempting to lower the PEL will cause a delay in providing this
- Similar to the respirator standard, OSHA should not allow employees to decline
participation in medical surveillance.
- OSHA should include requirements for multi-employer worksites.
- OSHA should consider using the DOT medical certificate and allow employees to take
their medical records from one employer to another for a period of 6-12 months.