Breathe Easier…OSHA’s Final Ruling on Respirable Silica 

Respirable Silica

The Occupational Safety and Health Administration (OSHA) has issued a final rule limiting worker exposure to respirable crystalline silica which should result in lower incidence of lung cancer, silicosis, chronic obstructive pulmonary disease and kidney disease in America's workers.

The rule is comprised of two standards, one which addresses Construction and one that is for General Industry and Maritime.

The final rule defines new exposure limits and action levels as well as outlining specific requirements for:

  • Employee exposure assessments
  • Exposure controls
  • Medical surveillance
  • Respiratory protection
  • Hazard communication
  • Recordkeeping


Approximately 2.3 million workers are potentially exposed to respirable crystalline silica in their workplace. This includes 2 million construction workers who drill, cut, crush, or grind silica-containing materials such as concrete and stone, and 300,000 workers in general industry operations such as brick manufacturing, foundries, and hydraulic fracturing (fracking), OSHA states.

The dangers of respirable crystalline silica have been a concern since the 1930s. Crystalline silica is a known human carcinogen that exists in sand, stone, soil, concrete as well as other materials. As workers crush, saw or cut these materials, silica particles are inhaled leading to lung diseases such as silicosis (scarring of the lungs which affects breathing) or lung cancer.

It wasn’t until OSHA’s creation in 1971 that any limits on exposure to respirable silica were set. Even so, the original rule only required that employers stay below the permissible exposure limit. No other requirements were in place, so often dust control measures to minimize exposure were not enough to provide adequate protection from silica-related diseases.

The intent of this rule, which has been in the rule-making process since 2003, is to update the standard to a level that provides adequate protection in existing industries as well as newer industries such as stone or artificial stone countertop fabrication.

Elements of the standard also address engineering controls, protective clothing, and medical surveillance.

The 2013 proposed rule received thousands of comments, but finally after roughly 13 years in the making, OSHA has finalized the Crystalline Silica Rule for General Industry and Maritime. The final rule was published in the Federal Register on March 25, 2016 with an effective date of June 23, 2016.

Are You Affected?

The new standard applies to any industry that uses sand as part of the manufacturing process, where employees could be exposed to respirable crystalline silica (quartz, cristobalite, and/or tridymite).

For the automotive industry, any foundries processing sand as part of the metal casting operation and blasting operations that use sand as the blast media would be affected.

What Does the New Standard Require?

The new silica rule not only redefines the permissible exposure limit, but also includes more stringent requirements affecting engineering controls, worker protection, training, and even medical exams.

Construction Worker Protect

The key provisions of the standard include:

  • Reducing the permissible exposure limit (PEL) for respirable crystalline silica to 50 micrograms per cubic meter of air, averaged over an 8-hour shift
  • Mandating that employers develop and implement engineering controls (such as water or ventilation) and work practices to restrict worker exposure to the PEL
  • Provide respiratory protection when engineering controls alone are not sufficient to limit exposure
  • Limit access to high-exposure sites
  • Develop and implement a written exposure control plan for tasks that involve exposure to crystalline silica
  • Adequately train employees on silica risks and methods to limit exposures, and
  • Offer medical exams to monitor highly exposed workers (exposed to levels over action levels for 30 or more days per year) and keep them apprised of their lung health.
  • Conducting initial exposure assessments for employees to determine if exposures for different job functions exceed the PEL or action level. Periodic sampling is required for employees that have exposures above the PEL (every 3 months) or the action level (every 6 months).
  • Implementing housekeeping provisions that minimize airborne crystalline silica through wet sweeping, HEPA vacuuming, or other methods.

While the rule increases the employer’s responsibility to adequately protect workers, it also provides a measure of flexibility to help employers, especially small businesses, protect workers from silica exposure.

Respiratory Silica

For example, OSHA created the table in response to small construction employers’ claims that measurement is expensive and difficult. The table outlines specified controls that construction employers can follow for “greater certainty and ease of compliance” without monitoring exposure.

The compliance schedule outlined in the ruling also spaces out compliance dates to allow employers to have enough time to satisfy requirements.

What’s the Compliance Schedule?

Both standards (construction and general industry/maritime) contained in the final rule take effect on June 23, 2016.

Industries have one to five years to comply with most requirements, based on the following schedule:

Construction - June 23, 2017, one year after the effective date.

General Industry and Maritime - June 23, 2018, two years after the effective date, allowing time for facilities to conduct exposure assessments and implement administrative and engineering controls. Additionally, medical surveillance is required to be in place for employees above the PEL (for 30 days or more) by June 23, 2018; medical surveillance isn’t required to be in place until June 23, 2020 for employees above the action level (for 30 days or more).

Hydraulic Fracturing - June 23, 2018, two years after the effective date for all provisions except Engineering Controls, which have a compliance date of June 23, 2021, allowing employers the opportunity to implement dust controls for the new PEL.

OSHA approved State Plans have six months to adopt standards that are at least as effective as federal OSHA standards.

NOTE: OSHA will delay enforcement of the respirable crystalline silica standard for construction until September 23, 2017, to conduct additional outreach and provide educational materials and guidance for employers. (see Memorandum link below for more details)

OSHA FAQs related to the silica rule (see link below for a full listing)

For a full listing of FAQs, go here.

What is crystalline silica?  Crystalline silica is a common mineral found in many naturally occurring materials and used in many industrial products and at construction sites. Materials like sand, concrete, stone and mortar contain crystalline silica. Crystalline silica is also used to make products such as glass, pottery, ceramics, bricks, concrete and artificial stone. Industrial sand used in certain operations, such as foundry work and hydraulic fracturing (fracking), is also a source of crystalline silica exposure. Amorphous silica, such as silica gel, is not crystalline silica.

Photo by https://www.osha.gov

How can exposure to crystalline silica affect workers’ health? Inhaling very small (“respirable”) crystalline silica particles, causes multiple diseases, including silicosis, an incurable lung disease that can lead to disability and death. Respirable crystalline silica also causes lung cancer, chronic obstructive pulmonary disease (COPD), and kidney disease.

Who is at risk from exposure to crystalline silica? Around 2.3 million workers are exposed to crystalline silica on the job. Simply being near sand or other silica-containing materials is not hazardous. The hazard exists when specific activities create respirable dust that is released into the air. Respirable crystalline silica – very small particles typically at least 100 times smaller than ordinary sand found on beaches or playgrounds – is generated by high-energy operations like cutting, sawing, grinding, drilling and crushing stone, rock, concrete, brick, block and mortar; or when using industrial sand. Activities such as abrasive blasting with sand; sawing brick or concrete; sanding or drilling into concrete walls; grinding mortar; manufacturing brick, concrete blocks, or ceramic products; and cutting or crushing stone generates respirable dust.

What is the relationship between silica exposure and lung cancer? There is strong scientific evidence showing that exposure to respirable crystalline silica can increase a person’s risk of developing lung cancer. The World Health Organization’s International Agency for Research on Cancer – the leading international voice on cancer causation – and the National Institutes of Health’s National Toxicology Program have conducted extensive reviews of the scientific literature and have designated crystalline silica as a known human carcinogen. The American Cancer Society has adopted the WHO and NIH’s determinations. More than 50 peer-reviewed epidemiological studies that OSHA evaluated for this rule-making have examined the link between silica exposure and lung cancer in at least 10 industries. In particular, several studies of workers in specific industrial sectors support the link between exposure to respirable crystalline silica and lung cancer among workers.

Photo by amienvironmental.com/

How will the crystalline silica rule protect workers’ health? The new rule requires that employers use engineering controls − such as ventilation and wet methods for cutting and sawing crystalline silica-containing materials − to reduce workers’ exposure to silica dust. Once the full effects of the rule are realized, OSHA expects it to prevent 600 deaths a year from silica-related diseases – such as silicosis, lung cancer, other respiratory diseases and kidney disease – and to prevent more than 900 new cases of silicosis each year.

Why is OSHA issuing a new crystalline silica rule? OSHA’s previous permissible exposure limits (PELs) for silica were outdated, inconsistent and did not adequately protect worker health. The previous PELs were based on studies from the 1960s and earlier that did not reflect more recent scientific evidence showing that low-level exposures to silica cause serious health effects, including lung cancer. In the 45 years since the previous PELs were established, the U.S. National Toxicology Program, the International Agency for Research on Cancer, and the National Institute for Occupational Safety and Health have all identified respirable crystalline silica as a human carcinogen. Previous construction and shipyard PELs were based on an old method of measuring worker exposures to silica that is not used today. Those previous limits are inconsistent, allowing permissible levels for construction and shipyards to be more than twice as high as levels in general industry. The revised rule will reduce the risk of disease among workers who inhale respirable crystalline silica and provide the same protection for all workers covered.

There is evidence of a decline of silicosis cases in recent years. Why is the rule necessary if the silicosis problem in the U.S. seems to be going away? Silicosis deaths have declined in recent years but the problem remains serious. From 2005  through 2014, silicosis was listed as the underlying or a contributing cause of death on over 1,100 death certificates in the United States, but most deaths from silicosis go undiagnosed and unreported. Also, those numbers of silicosis deaths do not include additional deaths from other silica-related diseases such as COPD, lung cancer and kidney disease. While the number of silicosis cases has declined over the past several decades, it is still a very serious workplace health problem. In fact, more workers died from silicosis in 2014 than in fires, or from being caught in or crushed by collapsing materials, such as in trench and structure collapses. Unless action is taken, new cases of silicosis could increase as workers are being exposed to respirable crystalline silica in some newer industries such as hydraulic fracturing and artificial stone countertop fabrication.

Photo by www.osha.gov

What is the new permissible exposure limit (PEL)? 

The PEL limits worker exposures to 50 micrograms of respirable crystalline silica per cubic meter of air (μg/m3), averaged over an eight-hour day. This level is the same for all workplaces covered by the standard (general industry/maritime and construction), and is roughly 50 percent of the previous PEL for general industry, and roughly 20 percent of the previous PEL for construction and shipyards. The National Institute for Occupational Safety and Health (NIOSH) first recommended this exposure limit to OSHA over 40 years ago, and the American Public Health Association has also recommended that OSHA adopt this PEL. The American Conference of Governmental Industrial Hygienists recommends an even lower exposure limit of 25 μg/m3 of air, averaged over an eight-hour day. OSHA established a PEL of 50 μg/m3 because the agency determined that occupational exposure to respirable crystalline silica at the previous PELs resulted in a significant risk of developing or dying from silicosis and dying from lung cancer, other lung diseases, or kidney disease, and that compliance with a 50 μg/m3 PEL would substantially reduce that risk. OSHA also finds significant risk remaining at the new PEL, but considers a PEL of 50 μg/m3 to be the lowest level that can reasonably be achieved through use of engineering controls and work practices in most affected operations.

What industries will be affected by the rule?

The main industries affected include:

  • Construction
  • Glass manufacturing
  • Pottery products
  • Structural clay products
  • Concrete products
  • Foundries
  • Dental laboratories
  • Paintings and coatings
  • Jewelry production
  • Refractory products
  • Landscaping
  • Ready-mix concrete
  • Cut stone and stone products
  • Abrasive blasting in:
    • Maritime work
    • Construction
    • General industry
    • Refractory furnace installation and repair
    • Railroads
    • Hydraulic fracturing for gas and oil
    • Asphalt products manufacturing

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