Roof Flashing Cut Dry on an Occupied Store
A roofing crew is replacing a low-slope roof on an occupied retail store. The flashing and associated roof cement contain 12% and 8% chrysotile, respectively. The crew will remove 300 linear ft of flashing and cement using reciprocating saws and an angle grinder. They plan to cut dry, sweep the debris into piles, and throw it into a dumpster. No wet methods, local exhaust, or respirators are planned. The roof hatch is open, and workers eat lunch on the roof near the work area. The store remains open below, and the rooftop HVAC units are running. The crew has had asbestos awareness training but no 40-hour worker training. The foreman argues that roofing work is exempt from asbestos rules and that the material is outside, so fibers will disperse. The project manager asks whether the job can proceed and what controls are needed.
1. Is the roofing material RACM, and is NESHAP notification required?
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The flashing and roof cement are asbestos-containing materials at 12% and 8%, above the 1% threshold. Dry cutting with saws and a grinder creates dust and can render the Material friable, making it RACM. The amount to be removed is 300 linear ft, which exceeds the 260 linear-foot NESHAP threshold. A renovation notification is therefore required, normally at least 10 working days before the work begins.
Roofing work is not automatically exempt because it is outdoors. The exemption analysis depends on the material, its condition, the removal method, and the amount. Dry cutting is especially problematic because it generates visible dust and contaminates the roof surface and nearby air intakes.
2. What engineering controls, work practices, and PPE should be required?
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The crew should stop dry cutting. Flashing and cement should be wetted and cut with HEPA-equipped local exhaust where feasible. Debris should be wetted, HEPA-vacuumed, and bagged or wrapped; dry sweeping is not acceptable. A regulated area should be established on the roof, with signs and restricted access. The roof hatch should be controlled so dust does not enter the store, and rooftop HVAC units should be shut down or isolated.
Workers need asbestos training, appropriate respirators, disposable coveralls, and decontamination before eating or leaving. No eating or drinking in the work area. Waste must be packaged and labeled. The store should be informed, and air monitoring should be conducted to verify that controls are working.
3. Personal monitoring shows an 8-hour TWA of 0.08 f/cc. How should the contractor respond?
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An 8-hour TWA of 0.08 f/cc is below the OSHA PEL of 0.1 f/cc but above the action level of 0.05 f/cc. That does not make the job safe or exempt. The contractor should evaluate task-based and short-term exposures, because grinding and cutting can produce peaks above the TWA. Engineering controls should be improved before relying on respirators.
Because the exposure is above the action level, the employer must consider the action-level triggers, including exposure monitoring and medical surveillance for eligible employees. Respirators should be used for dust-generating tasks as required by the standard and until controls are verified. The contractor should also re-monitor after changing work practices to confirm that exposure is controlled.