In a harbinger of things to come, OSHA recently released comprehensive guidance on controlling silica exposures in construction. The document is over 70 pages and details control methods for a variety of operations in construction, including:
- Stationary masonry saws
- Handheld masonry saws
- Hand-operated grinders
- Tuckpointing/mortar removal
- Rotary hammers and similar tools
- Vehicle-mounted rock drilling rigs
- Drywall finishing
The two control measures most commonly recommended throughout the document are:
- Wet methods, whereby water is sprayed at the source of the silica dust generation thus reducing the dust that can become airborne, and
- Vacuum dust systems, whereby grinders or other tools are equipped with a vacuum collection device that captures the silica released at the point of operation.
The document also provides guidance to employers on the current silica permissible exposure limit (PEL) for construction. The current PEL is expressed through millions of particles per cubic foot (mppcf). This “particle count” method is now obsolete and it has been giving the agency enforcement headaches for years. In the guidance document, the agency evaluates the effectiveness of controls not against the silica construction PEL, but against a benchmark 8-hour time-weighted average (TWA) exposure of .1 mg/m3 of respirable silica dust. The agency states that this benchmark level is actually lower than the current construction PEL and thus, for employers following the benchmark level, they will be in compliance with the construction PEL.
The guidance document is also important as an indicator of where OSHA is heading in its upcoming silica rulemaking. The data on which the recommendations in the guidance document are based will be the same as that used by the agency to justify the technological and economic feasibility of a final silica standard.
OSHA’s silica rulemaking is one of the Obama administration’s highest priorities. The next step in the rulemaking process is for OSHA to conduct a peer review of the proposed rule’s risk assessment and health effects. This early look at the agency’s risk assessment for silica will be valuable in seeing the agency’s plans for the PEL. Will it be lowered? And if so, by how much?
OSHA is focused on silica and the guidance document is just the first of more to come.