OSHA requirements are set by statute, standards and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at https://www.osha.gov.
August 29, 1996
Fernando M. Trevino, Ph.D., MPH
American Public Health Association
1015 Fifteenth Street, N.W.
Washington, D.C. 20005
Dear Dr. Trevino:
Thank you for your letter of June 23, requesting that the Occupational Safety and Health Administration (OSHA) adopt the Recommended Exposure Limit (REL) for crystalline silica from the National Institute for Occupational Safety and Health (NIOSH). OSHA recognizes the severe health hazards associated with over exposure to crystalline silica and continues to take steps to reduce the incidence of silicosis.
OSHA's priority planning process recognized crystalline silica as one of several chemical substances for promulgation as a final standard under rulemaking. When other rules, such as methylene chloride and butadiene, are completed and drop off our regulatory agenda, they will be replaced with hazards identified by the priority planning process. During the rulemaking procedures, OSHA will review the available studies and other recommended exposure limits including the NIOSH RELs and the American Conference of Governmental Industrial Hygienists threshold limit values (TLVs). The proposal of the rulemaking will be available for public comment once opened.
In the interim, until OSHA begins rulemaking on crystalline silica, we have implemented a special emphasis program for crystalline silica and silicosis (enclosed). The special emphasis program targets our agency resources to industries and facilities where the hazard of silicosis exists. The program will affect all industries including construction, maritime, and general industry.
A copy of your letter and our response has been forwarded to the Directorate of Health Standards Programs for their use and information. If you have any further questions or we can be of any further assistance please contact the Office of Health Compliance at (202) 219-8036.
Joseph A. Dear
June 23, 1996
Mr. Joseph A. Dear
Occupational Safety and Health Administration
200 Constitution Avenue, NW S-2315
Washington, DC 20210
Dear Mr. Dear:
At our 123rd Annual Meeting, the American Public Health Association (APHA), representing a combined national and affiliate membership of 55,000 public health professionals and community health leaders, adopted a resolution entitled "Prevention of Silicosis." A copy of the resolution is enclosed for your information.
Between 1968 and l99O, there were 13,744 deaths in the United States with silicosis as a primary or contributing cause of death. Although silicosis is usually a chronic disease which is often asymptomatic, its acute form (caused by massive levels of silica exposure) is a rapidly fatal disease which may develop in less than a year. In addition, silicosis is the only type of pneumoconiosis which predisposes an individual to tuberculosis.
Silicosis is entirely preventable with the implementation of conventional public health methods including the use of less hazardous materials, dust suppression techniques, improved ventilation, and respirator use. Due to the under-utilization of these techniques, however, it remains the most common type of pneumoconiosis.
APHA urges you to adopt the National Institute for Occupational Safety and Health (NIOSH) recommendations for silica exposure limits, and promote research toward the development of materials substitutes for abrasive blasting. These measures, combined with the increased monitoring of worker exposure to silica and an expansion of case identification efforts will form an effective preventive strategy.
Thank you for your time and consideration, and we look forward to receiving your views on this important issue.
Fernando M. Trevino, PhD, MPH
9512: Prevention of Silicosis
The American Public Health Association.
Recognizing that silicosis is the most common type of pneumoconiosis and that it is caused by inhalation of respirable silica dust (or quartz dust or silicon dioxide), the most common mineral in the earth's surface:(1) and Recognizing that silicosis is usually a chronic disease, developing over several years, and may be complicated with tuberculosis, and that massive exposure to silica can cause acute silicosis, a rapidly fatal disease that can develop in less than a year;(2) and Noting that cases of silicosis, even of acute silicosis, still appear in rock drill operators working on surface mines or highways, construction workers who use sand in abrasive blasting, and foundry workers who make sand castings and that recent deaths have occurred to men in their thirties;(2-4) and Recalling that between 1968 and 1990, there were 13,744 deaths in the United States with silicosis as a primary or contributing cause of death;(5) and Recognizing that the age-adjusted death rate in 1990 was 2.05 per million white men and 4.24 per million for black men, and that these rates have remained unchanged over the past ten years;(5) and Remembering that from 1985 to 1990, many different industries were recorded on silicosis death certificates, the most common being coal and metal mining (combined)(13.8 percent of cases), steelmaking (6.9 percent), miscellaneous non-mineral and stone products (6.1 percent), and iron foundries (5.4 percent);(5) and Noting that the Mine Safety and Health Administration (MSHA) and the Occupational Safety and Health Administration (OSHA) have both the mandate and the authority to regulate workers' exposure to silica; and
Recognizing that 26.9 percent of MSHA samples of mine air for respirable dust in 1991 exceeded the permissible exposure limit (PEL) and that this exposure limit is twice the value recommended by NIOSH (100 v. 50 micrograms per cubic meter);(5) and Acknowledging that silicosis is entirely preventable with known, effective, and conventional public health methods such as medical surveillance leading to secondary prevention and exposure surveillance leading to primary prevention; and
Noting that feasible and effective dust control methods include, from most to least adequate, use of less hazardous materials, dust suppression with water or enclosure of drill bits,(6) local exhaust ventilation, or use of respirators that have been fit-tested and worn by informed and trained workers who are physically able to wear them; and Recognizing that several countries in Europe (Sweden. United Kingdom, Germany) prohibit or restrict the use of sand in abrasive blasting;(7) therefore 1. Urges OSHA and MSHA to improve regulations and their enforcement for preventing silicosis by requiring exposure and medical monitoring, including surveillance for tuberculosis; improving exposure limits; restricting the use of silica; and enforcing these regulations vigorously;
2. Urges OSHA and MSHA to adopt the exposure limits recommended by NIOSH;
3. Suggests that OSHA and MSHA should require medical and exposure monitoring of workers exposed to silica and should prohibit the use of silica in abrasive blasting;
4. Urges OSHA and other agencies to investigate the use of safe alternative materials in foundries and to promote research that would identify substitute materials for abrasive blasting and sand casting, with additional funds being made available to these agencies if necessary;
5. Recommends that NIOSH continue and expand its efforts to identify cases through surveillance, investigating death certificates, and other means; and
6. Recommends health education of workers and families about prevention and treatment of silicosis.
1. Balaan MR, Banks DR. Silicosis. In Rom WN, ed., Environmental and Occupational Medicine, 2d ed. Boston: Little, Brown and Co., 1992;345-358.
2. National Institute for Occupational Safety and Health. Alert-Request for Assistance in Preventing Silicosis and Deaths among Rock Drillers. Cincinnati: U.S. Department of Health and Human Services, Public Health Service, 1992. DHHS(NIOSH) Publication No. 92-107.
3. National Institute for Occupational Safety and Health. Alert-Request for Assistance in Preventing Silicosis and Deaths from Sandblasting. Cincinnati: U.S. Department of Health and Human Services, Public Health Service, 1992. DHHS(NIOSH) Publication No. 92-102.
4. Morris J. Worked to Death. Houston Chronicle, Fall, 1994.
5. National Institute for Occupational Safety and Health, Division of Respiratory Disease Survellance. Work-Related Lung Disease Surveillance Report, 1994. Cincinnati: U.S. Department of Health and Human Service, Public Health Service, 1994. DHHS(NIOSH) Publication No. 94-120.
6. National Institute for Occupational Safety and Health. Industrial Health and Safety Criteria for Abrasive Blast Cleaning Operations. Washington, DC: U.S. Department of Health, Education, and Welfare (DHEW)(NIOSH) Pub. No 75-122.
7. PEI Associates, Inc. Investigation of Quartz Dust Sources and Control Mechanisms on Surface Coal Mine Operations. Vol I. Results, Analysis, and Conclusions. A mining research contract report, Contract No. J03348032. Pittsburgh: U.S. Department of the Interior, Bureau of Mines. March 1986.