The use of wet cutting controls, vacuum dust collection, and air monitoring by employers to protect employees from overexposure to crystalline silica is emphasized in a new OSHA publication, Controlling Silica Exposures in Construction.

The guidance focuses on controls that can be used with specific equipment and activities, primarily stationary masonry saws, handheld masonry saws, hand-operated grinders, tuckpointing/mortar removal, jackhammers, rotary hammers, vehicle-mounted rock drilling rigs, and drywall finishing.

Silica, which is known to cause silicosis, a lung disease, is subject to an OSHA permissible exposure limit (PEL) that was established in 1971 as a particle-count value. Laboratories have not used particle counting for crystalline silica analysis for many years, and exposure data are now reported gravimetrically.

In the guidance, OSHA uses a benchmark of 0.1 mg/m3 of respirable quartz as an 8-hour time-weighted average to describe the effectiveness of control measures. The benchmark is approximately equivalent to the general industry silica PEL.

Potential silica exposure levels will depend on the concentration of silica in materials at construction sites as well as factors in the work environment (e.g., enclosed, semi-enclosed, or open spaces, and/or multiple operations generating silica dust) as well as environmental conditions (e.g., wind direction and speed). Therefore, OSHA encourages employers to conduct periodic exposure monitoring to confirm that engineering and work practice controls are effective and that appropriate respiratory protection is being used where necessary.

OSHA¹s document is available here.

[Source: Environmental Manager's Compliance Advisor. Subscribe today!]