OSHA will be accepting comments on its proposed silica rule over the next three months, and a coalition of 11 construction trade associations says it "will assist OSHA in establishing a final rule on silica that protects workers without placing an undue burden on construction employers."

The coalition includes the Mechanical Contractors Association of America, the National Association of Home Builders, Associated General Contractors and other trade groups.

"OSHA's proposed rule is a good starting point," said Tom Skaggs, chairman of the safety and health committee for the Mechanical Contractors Association of America, and vice president-safety for the St. Louis-based Murphy Co.

"Several provisions in the proposed rule appear unnecessary for worker protection, and most likely will not be feasible for many construction firms. It is my hope that, by working with OSHA on the solution, [the Mechanical Contractors Association of America] and the coalition will be able to develop a practical rule for worker protection."

A practical rule "would adequately protect workers from overexposure without imposing unnecessary costs and burden on construction employers," the association asserted in a press release.

On Aug. 23, OSHA unveiled a proposed rule that would cut the permissible exposure limit in general industry, construction and shipyards to 50 micrograms of respirable crystalline silica per cubic meter of air.

The current silica-exposure limit in general industry is 100 micrograms per cubic meter of air, and the limit in construction is even higher.

OSHA estimates that 2.2 million workers – most of them in construction – are exposed to silica dust on the job.

The agency says its proposed rule would save nearly 700 lives and prevent 1,600 new cases of silicosis per year.

Silica is a common compound that can be harmful to humans when it is inhaled in high concentration over a period of time. Certain construction activities, such as pulverizing concrete, brick, block, tile and other silica-containing materials, generate silica-dust particles that are small enough to inhale.