No engineering controls are being used to control dust in this photo by NIOSH/John Rekus.


OSHA’s Permissible Exposure Limits (PELs) for silica are outdated and will be replaced by a new standard, according to OSHA Assistant Secretary Dr. David Michaels.

Speaking to attendees at AIHce 2011 in Portland, Oregon last week, Michaels commented that states are moving ahead of their federal level counterparts in modernizing silica health standards. “OSHA has to catch up to them,” Michaels said. “We need to rethink our PEL (for silica).”

Exposure to silica, a naturally-occurring compound, is linked to silicosis – an incurable and often fatal lung disease – as well as lung cancer, tuberculosis, emphysema, chronic bronchitis and renal disease. Current PELs set by OSHA, the Mine Safety and Health Administration (MSHA) and the National Institute for Occupational Safety and Health (NIOSH) do not lessen the health risk for workers exposed to respirable crystalline silica over a working lifetime, according to a2002 NIOSH study.

Airborne respirable silica particles are generated by a wide range of activities in mining, construction, concrete milling, abrasive blasting and sanding, and in work environments as diverse as dental labs and auto repair shops.

Michaels pointed to engineering controls like dust collection systems and wet methods as the most effective means of diminishing the risk for workers. “We know this can be done and we know it should be done,” he said.

He asked for comment on a silica health standard which he expects his agency to propose in the near future.