Occupational Safety and Health Administration OSHA

Silica Dust

Crystalline Silica: Proposed Rulemaking

On Sept. 12, 2013, OSHA published in the Federal Register a Notice of Proposed Rulemaking (NPRM) for Occupational Exposure to Respirable Crystalline Silica. The agency received over 2,000 comments on the proposed rule, amounting to about 34,000 pages of material. OSHA also held 14 days of public hearings, during which more than 200 stakeholders representing more than 70 organizations presented testimony. Hearing transcripts contain over 4,400 pages of testimony.

Inhalation of very small (respirable) crystalline silica particles puts workers at risk for silicosis, lung cancer, chronic obstructive pulmonary disease (COPD), and kidney disease. For information on the hazards associated with silica, please see our Silica Safety and Health Topics page. For more information on this rulemaking process, please see our updated FAQs.

In the NPRM, OSHA estimated that its proposed rule would save more than 600 lives and prevent more than 1,500 new cases of silicosis per year, once the full effects of the rule were realized.

The proposed rule was the result of extensive review of scientific evidence relating to the health risks of exposure to respirable crystalline silica, analysis of the diverse industries where worker exposure to crystalline silica occurs, and robust outreach efforts to affected stakeholders. OSHA carefully considered current industry consensus standards on crystalline silica exposure, recommendations from small business representatives, and input from other interested parties and partner agencies in developing the proposed rule.

OSHA currently enforces 40-year-old permissible exposure limits (PELs) for crystalline silica in general industry, construction and shipyards that are outdated, inconsistent among industries, and do not adequately protect worker health. The proposed rule would bring protections into the 21st century.

Select from the tabs at the top of the page to learn more about the proposed rule and silica hazards.

Without proper engineering controls, workers can be exposed to harmful levels of respirable crystalline silica that can cause silicosis, lung cancer, and other lung and kidney diseases (below)

Saw cutting Images

Courtesy New Jersey Department of Health

Applying water to a saw blade when cutting materials that contain crystalline silica — such as stone, rock, concrete, brick, and block — substantially reduces the amount of dust created during these operations (right)

Saw cutting Images

Courtesy Husqvarna AB

Silica Rulemaking Information/Press/Statements

News Releases


Assistant Secretary of Labor for Occupational Safety and Health Dr. David Michaels' Opening Statement at Silica Hearing [3/18/14]

Statements on Announcement of Proposed Rule:

Silica Blog

FACT SHEET: OSHA's Proposed Crystalline Silica Rule: Overview [PDF 430 KB] ] En español [PDF 375 KB]

FACT SHEET: Construction [PDF 445 KB] En español [PDF 428 KB]

FACT SHEET: General Industry & Maritime [PDF 525 KB] En español [PDF 497 KB]

FACT SHEET: Information for Small Businesses [PDF 485 KB] En español [PDF 449 KB]

Frequently Asked Questions (FAQs) [PDF 183 KB]

Notice of Proposed Rulemaking (NPRM)
The NPRM is OSHA's formal notice of regulatory action related to Occupational Exposure to Crystalline Silica. The NPRM contains some background information on analyses related to the proposed rule, as well as the proposed regulatory text. OSHA welcomes public comments on the NPRM.

Health Effects & Risk Assessment Background Documents [PDF 2.28 MB]
As part of the rulemaking process, OSHA carefully evaluated health effects of and the risk of morbidity and mortality associated with occupational exposure to crystalline silica. A Health Effects Supplement [PDF] contains OSHA's assessment of additional literature published after its preliminary analysis was complete. OSHA welcomes public comments on these background documents.

Preliminary Economic Analysis (PEA) [PDF 12 MB]
The PEA details OSHA's estimation of costs, benefits, and other economic impacts of the proposed rule. OSHA welcomes public comments on the PEA.

Employment Analysis [PDF 397 KB]
Inforum, an independent, not-for-profit research entity, estimated the industry and aggregate employment effects of the proposed silica rule

Federal Docket for Silica Rulemaking
Visit the federal docket folder on Regulations.gov to examine supporting materials for the proposed rule and review comments submitted by other members of the public, workers and worker groups, affected industries, and other interested parties. However, some information (e.g., copyrighted material) is not publicly available to read or download through that website. All submissions to the docket, including copyrighted material, are available for inspection and, where permissible, copying at the OSHA Docket Office, U.S. Department of Labor, Room N-2625, 200 Constitution Avenue NW, Washington, DC 20210.

Hearing Information

Hearing Schedule

Hearing Procedures

Amendment to Hearing Procedures

Second Amendment to Hearing Procedures

Scientific and Technical Resources

Additional Resources

Safety & Health Topics Page on Crystalline Silica
OSHA's Safety & Health Topics page on Crystalline Silica is the Agency's main resource for information about silica hazards, health effects, control methods, and other standards applicable to protecting workers who are exposed to respirable crystalline silica on the job.

MSHA Silicosis Prevention web page
The Mine Safety & Health Administration (MSHA) provides information about silica hazards specific to the mining industry. Miners and mine employers can find useful information about hazard identification and control from this page.

NIOSH Silica Information web page
The National Institute for Occupational Safety & Health (NIOSH) has conducted extensive research about health hazard identification and control for respirable crystalline silica.

Archived Silica Web Chat


Silica Rulemaking FAQs

Respirable crystalline silica is a deadly dust created almost any time a worker cuts, saws, grinds, or drills stone, rock, concrete, brick, block or mortar. Crystalline silica is a common mineral found in the Earth's crust, and is present in sand, concrete, stone, mortar, and other similar materials. These tiny particles (about 100 times smaller than ordinary beach sand) are common in construction work, as well as brick, concrete and pottery manufacturing operations, and during operations using industrial sand products, such as in foundries, sand blasting and fracking operations.

Yes. Silica exposure has been linked to many diseases, including silicosis, lung cancer, kidney disease and emphysema. Every year hundreds of people die in the U.S. from preventable silica-related diseases, including silicosis. From 2009 to 2013, silicosis was listed as the underlying or contributing cause of death on more than 500 U.S. death certificates, however most people who die from silicosis go undiagnosed.

Crystalline silica becomes dangerous when it becomes respirable. Activities that generate respirable dust include: using sand in abrasive blasting; sawing brick or concrete; sanding or drilling into concrete walls; grinding mortar; manufacturing brick, concrete blocks or ceramic products; and cutting or crushing stone. OSHA estimates that over two million workers are exposed to respirable crystalline silica.

We've known for decades that inhaling silica is harmful to health, and that its negative effects are preventable. Studies from a variety of scientific organizations, including the American Cancer Society and NIOSH, show that silica kills and sickens hundreds of workers every year, from diseases including silicosis, emphysema, chronic bronchitis, kidney disease, and lung cancer. OSHA's assessment of the risk and health effects was independently peer-reviewed by some of the nation's leading experts on the health effects of silica.

The current standards don't offer enough protection for workers. The current permissible exposure limits (PEL) for silica were established in 1971. Studies conducted since then show that workers can still get sick or die when exposed to silica at the permissible levels. In order to better protect workers, we need to set new rules that lower the amount of silica to which they can be exposed. In addition, we need to ensure that these new limits are part of a thoughtful plan to control silica dust before workers are exposed to it. A comprehensive standard would ensure that employers use dust controls to protect workers and provide medical exams to highly exposed workers.

Even with 100% compliance with current standards, workers would still be at high risk of getting sick or dying. Peer-reviewed risk assessments performed by OSHA, NIOSH and others show that exposure at the current general industry permissible exposure limit results in highly significant risks of dying of lung cancer, kidney disease, silicosis, or other lung diseases. Risks are even higher at the current permissible exposure limit (PEL) for construction and shipyards, which is over twice as high as the general industry PEL. Simply enforcing the current limits will not substantially reduce or eliminate this risk.

No. OSHA is required by its law to only issue standards that are economically feasible for affected industries. The proposed rule issued in 2013 estimated that the benefits of changing the permissible exposure limit would be significantly higher than the costs. Net benefits were estimated at about $4.6 billion a year. The agency received many comments addressing potential costs which were estimated at $640 million a year, which will be factored into the final rule. It's also worth noting that a 1995 review of past OSHA actions found that OSHA generally overestimates potential regulatory costs.

Before proposing a rule in 2013, the agency consulted with small businesses through the Small Business Regulatory Enforcement Fairness Act process and incorporated many of the recommendations in the notice of proposed rulemaking. After the proposal, OSHA sought and received extensive feedback. Altogether, OSHA received more than 2,000 public submissions from stakeholders, containing more than 34,000 pages of materials. OSHA also held 14 days of public hearings, during which more than 200 stakeholders from more than 70 organizations presented testimony. Small entities were invited to provide written comments and to participate in public hearings during the comment period, and many of them did. The entire public comment period lasted almost one year.

OSHA requested input from businesses of all sizes throughout the rulemaking process. Small business representatives reviewed an early draft of the standard during the Small Business Regulatory Enforcement Fairness Act review and OSHA made significant changes that were reflected in the proposed rule itself, as well as to the cost, impact and other analyses contained in the proposal. More than 200 stakeholders representing more than 70 organizations presented testimony during the 2014 public hearings, including many small business representatives.

The rule has not yet been finalized, so we cannot discuss how it differs. The details of the proposed rule can be read here. OSHA has conducted extensive outreach since the proposal was published, and the thousands of submissions received during the comment period have been taken into account in drafting the final rule.

The silica standard is one of the largest and most complex worker protection standards ever issued by OSHA. The agency conducted extensive outreach and solicited feedback from a variety of sources over a period of years. The agency issued a notice of proposed rulemaking in August 2013. We extended the comment period and we held 14 days of public hearings from March 18 to April 4, 2014. Following the public hearings, we provided the public with 60 additional days to submit evidence and 136 more days to submit final comments OSHA will use all of this information to develop a final rule based on the best available evidence in the complete rulemaking record.

Many factors are involved in the publication of a final rule, making it impossible to predict exactly when the rule will be published, but OSHA hopes to publish the final rule in early 2016.

OSHA's Notice of Proposed Rulemaking (NPRM) for Occupational Exposure to Respirable Crystalline Silica was published in the Federal Register on September 12, 2013. The NPRM is available from the Federal Register in print (Document number: 2013-20997) or online at https://federalregister.gov/a/2013-20997.

Contractors adopt innovative concrete drill jig to reduce silica exposures during concrete drilling operations

Contractors adopt innovative concrete drill jig to reduce silica exposures during concrete drilling operations. Read more.

1938 "Stop Silicosis" Video

This 1938 video features former Secretary of Labor, Frances Perkins (1933-1945), and describes both the hazards associated with silica exposure and the U.S. Department of Labor's early efforts to ensure safe and healthful working conditions for America's working men and women. Although tremendous progress has been made since this video was produced, evidence indicates that a substantial number of workers still suffer from silica-related diseases. This video is available for download at http://archive.org/details/StopSilicosis

What is Crystalline Silica?

Respirable crystalline silica – very small particles at least 100 times smaller than ordinary sand you might encounter on beaches and playgrounds – is created during work operations involving stone, rock, concrete, brick, block, mortar, and industrial sand. Exposures to respirable crystalline silica can occur when cutting, sawing, grinding, drilling, and crushing these materials. These exposures are common in brick, concrete, and pottery manufacturing operations, as well as during operations using industrial sand products, such as in foundries, sand blasting, and hydraulic fracturing (fracking) operations in the oil and gas industry.

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