What is Respirable Crystalline Silica?
Crystalline silica is a common mineral found in many naturally occurring and man-made materials used at construction sites. Materials like sand, concrete, brick, block, stone and mortar contain crystalline silica. Amorphous silica, such as silica gel, is not crystalline silica. 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 abrasive blasting with sand.
What are the Risks?
Workers exposed to respirable crystalline silica are at increased risk of developing serious adverse health effects including silicosis, lung cancer, chronic obstructive pulmonary disease, and kidney disease. Approximately 2 million construction workers that drill, cut, crush or grind silica-containing materials like concrete, quartz, and stone are exposed to respirable crystalline silica. Another 300,000 workers in brick manufacturing, foundries, and hydraulic fracturing also are exposed to breathing the material, which in severe cases can be disabling and fatal. The respirable silica enters the lungs and creates scar tissue, reducing the ability to take in oxygen.
When are workers at risk from exposure?
According to OSHA, the most severe exposures for construction workers arise from the use of abrasive blasting with sand to remove paint and rust from bridges, tanks, concrete structures and other surfaces. Other activities that may result in severe exposure include jackhammering, rock/well drilling, concrete mixing, concrete drilling, brick-and-concrete block cutting, and tunneling operations.
OSHA’s final rule reduces the permissible exposure limit for respirable crystalline silica to 50 micrograms per cubic meter of air over an average eight-hour shift. To comply with the rule, OSHA urges employers to use engineering controls that limit worker exposure, provide respirators when engineering controls fail to adequately limit such exposure; and train workers on silica risks, among other guidance. The rule became enforceable for construction entities on June 23, 2017.
For more information:
Construction Workers Standards
OSHA’s Respirable Crystalline Silica standard for construction requires employers to limit worker exposures to respirable crystalline silica and to take other steps to protect workers. The standard provides flexible alternatives, which OSHA expects will be especially useful for small employers. Employers can either use the control methods laid out in the table below (example shown for use of saws), or they can measure workers’ exposure to silica and independently decide which dust controls work best to limit exposures to the PEL in their workplaces.
Regardless of which exposure control method is used, all construction employers covered by the standard are required to:
- Establish and implement a written exposure control plan that identifies tasks that involve exposure and methods used to protect workers, including procedures to restrict access to work areas where high exposures may occur.
- Designate a competent person to implement the written exposure control plan.
- Restrict housekeeping practices that expose workers to silica where feasible alternatives are available.
- Offer medical exams-including chest X-rays and lung function tests-every three years for workers who are required by the standard to wear a respirator for 30 or more days per year.
- Train workers on work operations that result in silica exposure and ways to limit exposure.
- Keep records of exposure measurements, objective data, and medical exams.
Construction employers must comply with all requirements of the standard, including requirements for laboratory evaluation of exposure samples, which began on June 23, 2018.
Resources for the Construction Industry are available at:
ABCO Supply can help you prepare for these inspections to ensure you are OSHA compliant. We have a range of products to support you to minimize exposure.