OSHA objective data guide
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.
Roadmap for Meeting the Requirements of the Respirable Crystalline Silica Standard
1. Determine if the silica standard applies to your employees.
Could employees be exposed to respirable crystalline silica at or above 25 µg/m3 as an 8-hour TWA under any foreseeable conditions, including the failure of engineering controls, while performing construction activities?
No: No further action is required under the silica standard.
Yes: Choose to comply with the standard using either the:
• Specified exposure control methods in Table 1, or
• The alternative methods of compliance
2. Determine what additional requirements you must meet under the standard, based on the compliance method you are following.
Action level means an airborne concentration of 25 μg/m3 calculated as an 8-hour TWA. Exposures at or above the action level trigger requirements for exposure assessment.
Competent person means an individual who is capable of identifying existing and foreseeable respirable crystalline silica hazards in the workplace and who has authorization to take prompt corrective measures to eliminate or minimize them. The competent person must have the knowledge and ability necessary to implement the written exposure control plan required under the standard.
Employee exposure means the exposure to airborne respirable crystalline silica that would occur if the employee were not using a respirator.
Objective data means information, such as air monitoring data from industrywide surveys or calculations based on the composition of a substance, demonstrating employee exposure to respirable crystalline silica associated with a particular product or material or a specific process, task, or activity. The data must reflect workplace conditions closely resembling or with a higher exposure potential than the processes, types of material, control methods, work practices, and environmental conditions in the employer’s current operations.