U.S. Proposes New Silica Limits


Federal regulators have finally released a long-awaited—and certain to be controversial—proposal to limit worker exposure to respirable crystalline silica, widely used in construction, painting and abrasive blasting activities.

The proposal—which has languished in the White House Office of Management and Budget for more than two years—includes a new exposure limit for crystalline silica and details methods for controlling worker exposure, conducting medical surveillance, training workers about silica-related hazards, and recordkeeping measures.

The proposed rule would save nearly 700 lives per year and prevent 1,600 new cases of deadly silicosis annually, the Occupational Safety and Health Administration said Friday (Aug. 23) in announcing the Notice of Proposed Rulemaking.

The proposed rulemaking includes two separate standards—one for general industry and maritime employment, and one for construction.

2M+ Workers

Silica is one of Earth's most common minerals, found in stone, rock, brick, mortar and block. Exposure to airborne silica dust occurs in operations involving cutting, sawing, drilling and crushing of concrete, brick, block and other stone products and in operations using sand products, such as in glass manufacturing, foundries and abrasive blasting.

More than two million American workers are currently exposed to respirable crystalline silica, according to OSHA. More than 640,000 are believed to be exposed to silica levels that exceed the current Permissible Exposure Limits.

OSHA silica exposure table

The new rule would update 40-year-old Permissible Exposure Limits for crystalline silica in general industry, construction and shipyards "that are outdated, inconsistent between industries, and do not adequately protect worker health," OSHA says on a website devoted to the proposal. The current PEL for construction and shipyards is based on particle counting technology, which is considered obsolete.

"The proposed rule brings protections into the 21st century," OSHA says.

“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.”

Major Provisions

Michaels said the new proposed rule contained "common sense precautions" that many employers already use.

Both proposed standards include provisions for employers to:

  • Measure the amount of silica that workers are exposed to if it may be at or above an action level of  25 μg/m3 (micrograms of silica per cubic meter of air), averaged over an eight-hour day;
  • Protect workers from respirable crystalline silica exposures above the Permissible Exposure Limit (PEL) of 50 μg/m3, averaged over an eight-hour day;
  • Limit workers’ access to areas where they could be exposed above the PEL;
  • Use dust controls to protect workers from silica exposures above the PEL;
  • Provide respirators to workers when dust controls cannot limit exposures to the PEL;
  • Offer medical exams—including chest X-rays and lung function tests—every three years for workers exposed above the PEL for 30 or more days per year;
  • Train workers on operations that result in silica exposure and ways to limit exposure; and
  • Keep records of workers’ silica exposure and medical exams.

Painter's Death Highlighted

OSHA's announcement of the proposed rule was accompanied by a new website and a new nine-minute video, Deadly Dust: Silica,  to support its case. The video is woven around the story of Bill Ellis, a professional painter and abrasive blaster who died of silicosis.

The video also includes interviews with experts, victims' families, and evidence of the hazards posed by silica exposure on the job. One safety consultant likens the effects of silicosis to slow suffocation. A third-generation stone carver describes the deaths of his father and grandfather from silicosis.

Construction and safety personnel discuss the use of controls to effectively control silica dust.

Michael Mangum, a spokesman for the National Asphalt and Pavement Association, says, "Our belief is that the very best thing you can do to protect a company is to protect the workers who are, in effect, the heart and soul of that company."

Dr. William Bennett, an assistant professor of medicine at Harvard Medical School, reports: "People are still dying of silicosis in the United States." 

And Michaels says: "This standard is about saving lives."

To emphasize how long the dangers of silica have been known, OSHA also re-released an 11-minute video, Stop Silicosis, made in 1938 with then-Labor Secretary Frances Perkins.

The Process

The proposed rule has been submitted for publication in the Federal Register. After publication, the public will have 90 days to submit written comments, followed by public hearings. After that, members of the public who filed a notice of intention to appear may submit additional post-hearing comments.

Additional information on the proposed rule and process may be found here.

OSHA says 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."

Long Wait

The agency has been talking about a new silica rule for decades. It tried a variety of non-regulatory approaches, including a Special Emphasis Program on silica in October 1997, co-sponsoring a National Conference to Eliminate Silicosis, and presenting guidance information on its Web site.

The agency completed its Small Business Regulatory Enforcement Fairness Act (SBREFA) on a proposed rule in December 2003. In May 2009, OSHA initiatied a seven-month peer review of health affects and risk assessment. 

In February 2011, OSHA sent the proposed rule to the White House Office of Management and Budget for what was supposed to be a 90-day review. While labor unions and worker health advocates fumed, the proposed rule was pushed back to the end of 2011; then to 2012; then to the spring and, finally, the summer of 2013.

(While the proposal waited, OSHA issued a Hazard Alert last year regarding silica exposure of workers in the hydraulic fracturing (fracking) industry.)

Friday's release, two and a half years later, signaled the end of the OMB review.

For and Against

Long before its release, the proposed rule was drawing a sharply mixed reaction.

In June, the Industrial Minerals Association – North America announced that it favored "protective measures," but not lower PELs, for crystalline silica. The National Association of Manufacturers told NPR in February that the rule was unnecessary, given the decline in silicosis deaths.

"The rule would cost manufacturers and the industry as a whole billions of dollars a year that is just not sustainable for manufacturing when employers are looking to hire and create new opportunities for job creation," said spokeswoman Amanda Wood.

The Chamber of Commerce called the silica rule "not appropriate for revision."

However, a spokesman for the Associated of General Contractors applauded the revisions, saying that employers frequently flout the current limits.

Other Efforts

The U.S. is not the only jurisdiction acting on silica. In June, the Canadian province of British Columbia also proposed a rule limiting silica expsoure.

Despite what is likely to be a rough rule-making road ahead, Michaels sounded confident that a rule would be approved eventually.

“The proposed rule uses common sense measures that will protect workers’ lives and lungs—like keeping the material wet so dust doesn’t become airborne,” he said. “It is designed to give employers flexibility in selecting ways to meet the standard.”


Tagged categories: Abrasive blasting; Construction; Health & Safety; Health and safety; Painters; Shipyards; Silica; Surface preparation

Join the Conversation:

Sign in to our community to add your comments.