OSHA recently published a proposed regulation…
to limit worker exposure to crystalline silica. According to OSHA, the proposed rule would save nearly 700 lives per year and prevent 1,600 new cases of deadly silicosis annually. The proposed standard includes the following provisions:
- Establishes an Action Level of 25 μg/m3 (micrograms of silica per cubic meter of air), averaged over an eight-hour day;
- Requires protecting workers from crystalline silica exposures above the Permissible Exposure Limit (PEL) of 50 μg/m3, averaged over an eight-hour day;
- Limits worker access to areas where they could be exposed above the PEL;
- Requires the use of dust control methods (e.g. ventilation, use of vacuum shrouds on power tools, substitutes for silica sand, re-engineering of material handling equipment to emit less dust, wetting down roads) to protect workers from crystalline silica exposures above the PEL ;
- Requires that employers provide respirators to workers when dust controls cannot limit exposures to the PEL;
- Requires that employers 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;
- Requires that employers train workers on operations that result in crystalline silica exposure and ways to limit exposure; and
- Requires that employers keep records of workers’ crystalline silica exposure and medical exams.
While this standard is currently only in the proposal stage, OSHA already requires employers to limit employee exposures to below the current PEL. Control of worker exposures is also required through a number of currently enforced OSHA standards such as respiratory protection and hazard communication.
The proposed rule would impose new requirements for employers in the hydraulic fracturing, industrial painting, construction, and manufacturing industries. A brief discussion regarding the ways in which each of these industries can be affected by the proposed rule is provided below:
Silica sand is routinely used in hydraulic fracturing operations, typically as a proppant or material that holds open the fractures in the shale formation formed in the hydraulic fracturing process. The extent of potential worker exposures to crystalline silica during hydraulic fracturing was illustrated by the following findings in a recent study published by the National Institute of Occupational Safety and Health (NIOSH):
- 47% of air sample results exceeded the current OSHA Permissible Exposure Limit
- In addition to workers directly engaged in sand moving operations, workers not in the immediate vicinity of sand moving operations (i.e., workers spotting trucks who were possibly exposed to dust created by vehicle traffic) also had elevated exposures to crystalline silica. While below the OSHA Permissible Exposure Limit, these exposures did exceed the Recommended Exposure Limit published by NIOSH.
While silica sand is not commonly used as an abrasive during surface preparation, industrial painters can still be exposed to silica in the following common industrial painting tasks:
- Removal of paint containing silica. A study published in the Journal of Occupational and Environmental Hygiene in September 2002 found that abrasive blasting of bridge structural steel resulted in exposures to crystalline silica. These exposures exceeded the Threshold Limit Value recommended by the American Conference of Governmental Industrial Hygienists. While silica sand was not used in the blasting process, the silica content in the paint system being removed was high enough to cause elevated exposures.
- Abrasive blasting of concrete surfaces
- Abrasive blast cleaning using silica sand
According to OSHA, 1.85 million workers in the construction industry are potentially exposed to crystalline silica. 640,000 of these workers are estimated to be exposed to crystalline silica above the proposed OSHA PEL. Exposures can occur when workers cut, grind, crush or drill silica containing materials such as concrete, masonry, tile and rock. Exposures can also occur to operators of equipment.
According to OSHA, 325,000 workers in manufacturing facilities are potentially exposed to crystalline silica. Examples of affected industries include the following:
- Brick, concrete, and pottery
Other manufacturers may have workers exposed to crystalline silica if abrasive blasting is performed at their facility and silica sand is used or if paint that is being removed contains crystalline silica.
KTA Certified Industrial Hygienists and Certified Safety Professionals are able to assist employers with regulatory compliance and the control of worker exposure to crystalline silica. Example services available from KTA include:
- Worker exposure air sampling
- Compliance program development
If you have any questions regarding the proposed rule, or would like additional information regarding crystalline silica, please contact Mr. Dan O’Malley or Mr. Stanford Liang, CIH, CSP of the KTA Environmental, Health and Safety Department. Mr. O’Malley can be reached at 412.788.1300, extension 138 or via e-mail at firstname.lastname@example.org. Mr. Liang can be reached at 412.788.1300, extension 219 or via e-mail at email@example.com.
Dan O’Malley is the Manager of the EH&S Group for KTA where he has been employed for over 19 years. In this position, Dan serves EH&S clients (while also assisting other KTA groups on multi-disciplinary projects) by reviewing/developing safety and health programs, facilitating/evaluating laboratory results, preparing proposals, developing specifications for removal of coatings containing lead and other toxic metals, performing ambient air monitoring activities (i.e., site evaluation), scheduling staff and consulting on industrial hygiene and safety issues.