Dry Cutting Concrete With No Silica Controls
Bedrock Concrete Cutting is using a gas-powered hand saw to cut a 6-inch concrete slab for about 6 hours. The saw has a water kit, but the water tank is broken, so the crew is cutting dry. Two workers wear disposable dust masks that were bought at a hardware store; they have not been fit-tested or medically evaluated. The employer has no exposure monitoring, no silica training, and no medical surveillance. A worker asks whether the visible dust is harmful. The foreman says, 'Concrete dust is just dirt; we've done it this way for 20 years.' The crew is paid by the linear foot and wants to finish today.
1. What does OSHA's silica standard require for this hand-held saw task, and can the crew continue dry cutting as described?
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For a hand-held power saw, the silica standard's Table 1 approach requires integrated water delivery that continuously feeds water to the blade. If the employer does not use Table 1, it must use another exposure-control method supported by objective data or an exposure assessment, and it must provide respiratory protection as required.
The crew cannot continue dry cutting as described. The water kit is broken, there is no assessment or objective data, and the visible dust indicates a likely exposure problem. The employer should stop the dry cutting, repair or replace the water delivery, and if that cannot be done immediately, reassess the task and provide appropriate respiratory protection and other controls.
2. Are the disposable dust masks adequate? What must the employer do about respirators?
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The disposable dust masks are not adequate as used. If respirators are required, they must be NIOSH-approved for the hazard, and the employer must provide medical evaluation, fit testing, training, and maintenance. A hardware-store dust mask that has not been fit-tested may leak badly and may not provide enough protection for high silica exposures.
The employer should determine the exposure level and select a respirator with an adequate assigned protection factor. The employer cannot simply hand out masks and tell workers to wear them.
3. What training and medical surveillance obligations are triggered, and what should the employer tell the workers now?
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The employer must train workers on the silica hazard, the tasks that create exposure, the controls being used, and the proper use of respirators. Medical surveillance is required for employees who are exposed at or above the permissible exposure limit for 30 or more days per year; it must be offered, not merely mentioned.
Right now, the employer should tell the workers that the dust is not 'just dirt': respirable crystalline silica can cause silicosis and other diseases. The employer should explain the water control, why dry cutting is stopping, and what respirators and work practices will be used. Telling the crew to finish quickly because they are paid by the linear foot would undermine the controls.