The U.S. Department of Labor’s Occupational Safety and Health Administration announced a proposed rule aimed at curbing silica-related disease. After publication, the public will have 90 days to submit written comments, followed by public hearings.

“Exposure to silica can be deadly, and limiting that exposure is essential,” said Dr. David Michaels, assistant secretary of labor for occupational safety and health. “Every year, exposed workers not only lose their ability to work, but also to breathe. This proposal is expected to prevent thousands of deaths from silicosis—an incurable and progressive disease—as well as lung cancer, other respiratory diseases and kidney disease. We’re looking forward to public comment on the proposal.”

The proposal is based on extensive review of scientific and technical evidence, consideration of current industry consensus standards and outreach by OSHA to stakeholders, including public stakeholder meetings, conferences and meetings with employer and employee organizations.

Niosh recently published findings in the Journal of Occupational and Environmental Hygiene that showed at 11 hydraulic fracturing sites where it conducted personal monitoring, the concentration of silica in the air workers breathe exceeded the permissible exposure limits set by OSHA. Researchers measured the silica levels of more than 100 personal-breathing-zone samples at hydraulic fracturing, or fracking, sites in five states. They discovered that in some cases the samples exceeded OSHA’s limits by a factor of 10 or more. “Occupational exposure to respirable crystalline silica is a well-established hazard in mining, sandblasting, foundry work, agriculture and construction, but not for oil and gas extraction work, which includes hydraulic fracturing,” NIOSH said. “To our knowledge, this represents the first systematic study of work crew exposures to crystalline silica during hydraulic fracturing. Companies that conduct hydraulic fracturing using silica sand should evaluate their operations to determine the potential for worker exposure to respirable crystalline silica and implement controls as necessary to protect workers.”

OSHA’s proposed silica rulemaking will include two separate standards—one for general industry and maritime employment, and one for construction. Employers in the oil and gas industry will be required to comply with the standard for general industry.

The proposed rule will include a new exposure limit for respirable crystalline silica and details widely used methods for controlling worker exposure, conducting medical surveillance, training workers about silica-related hazards and recordkeeping measures. Additional information on the proposed rule, including a video; procedures for submitting comments and the public hearings can be found here.