US slashes exposure limit for silica dust

The US’ federal Occupational Safety and Health Administration (OSHA) has issued new, stronger rules to protect workers from silica dust, updating the standards adopted in 1971. OSHA has determined that employees exposed to respirable crystalline silica – a component of soil, sand, granite, and many other minerals – at the previous permissible limits face significant health risks such as developing lung fibrosis known as silicosis and other non-malignant respiratory diseases, as well as lung cancer and kidney disease.

The final OSHA rule, published on 25 March, establishes a new permissible exposure limit (PEL) of 50 micrograms of respirable crystalline silica per cubic meter of air (50 µg/m³), averaged over an eight-hour shift in the general industry as well as in the maritime and construction industries. This new PEL represents about 50% of the previous PEL for general industry, and roughly 20% of the previous PEL for shipyards and construction.

The new standards will take effect on 23 June, after which industries have one to five years to comply with most of the requirements.

OSHA estimates that its new regulation will save over 600 lives and prevent more than 900 new cases of silicosis each year, providing about $7.7 billion (£5.35 billion) in net benefits annually. But the National Association of Manufacturers called the new regulation ‘fundamentally flawed’, and accused OSHA of basing its new standards on out-of-date economic data. They said the agency significantly underestimated the costs that will be passed on to US manufacturers, and warned that small and medium-sized manufacturers could be forced to close.