The U.S. Department of Labor’s Occupational Safety and Health Administration (OSHA) is soon set to release new exposure limits to air-borne silica dust. The rulemaking has been in the works for about three years with a final rule scheduled to be announced this year. The silica industry is not enthused.
Silica dust is known to cause respiratory illnesses (e.g., silicosis, lung cancer, other airways diseases) that may contribute to or lead directly to death when it is breathed in high enough concentrations over long enough time periods.
OSHA explains that exposure to respirable silica “occurs in operations involving cutting, sawing, drilling and crushing of concrete, brick, block and other stone products and in operations using sand products, such as in glass manufacturing, foundries and sand blasting.”
OSHA’s proposal, generally, is to lower the existing permissible exposure limits (adopted in 1971) by about 50%, dropping them from around 0.1mg/m3 to 0.05mg/m3 (specific details here). OSHA explains:
The agency currently enforces 40-year-old permissible exposure limits (PELs) for crystalline silica in general industry, construction and shipyards that are outdated, inconsistent between industries and do not adequately protect worker health. The proposed rule brings protections into the 21st century.
And, as the government likes to claim with all of its regulations, the added restrictions will save lots of lives, and in doing so, will save lots of money:
OSHA estimates that the proposed rule will save nearly 700 lives and prevent 1,600 new cases of silicosis per year once the full effects of the rule are realized.
The proposed rule is estimated to provide average net benefits of about $2.8 to $4.7 billion annually over the next 60 years.
Interestingly, a visit to the Centers for Disease Control in search of deaths from silica inhalation produces this chart graphing silicosis mortality over time. The numbers have dropped considerably over the past 40+ years, and by 2010 had fallen to about 100 or so deaths per year (U.S. residents over the age of 15) attributed to silicosis as either the underlying or contributing cause.
Figure 1. Silicosis: Number of deaths, crude and age-adjusted death rates, U.S. residents age 15 and over, 1968–2010 (Source: CDC).
The CDC data shows that silicosis deaths have been declining and although the decline has slowed, it continues to drop while under the current OSHA guidelines. And further, the 100 or so deaths that are occurring annually are several times less than the annual number of deaths that OSHA predicts will be saved by the new regulations. That’s a pretty neat trick—the new regs are going to save several times more lives than are actually lost!