As a rule, no silica is good silica.
That actually is a rule of the Occupational Safety and Health Administration. Or in the words of the U.S Circuit Court of Appeals for the District of Columbia, it is "no exposure level below which workers would not be expected to develop adverse health effects."
Industry groups had challenged the zero tolerance rule, which is designed to protect workers from exposure to the chemical compound. But in North America's Building Trades Unions v. Occupational Safety & Health Administration, the appeals court upheld it.
OSHA published the rule in 2016, regulating exposure for workers who come into contact with crystalline silica. It is often found in worksites that have rock, sand, gravel and similar materials, and long-term exposure can cause lung disease -- even death.
The trade unions challenged the rule last year, claiming the research on silica exposure was not definitive. The "no threshhold" rule was "inconsistent with common sense," they said.
The DC Circuit disagreed. The appeals court said the OSHA rule was based on studies that showed "a statistically significant association between silicosis mortality and cumulative exposure."
The court discounted arguments that other factors, such as smoking, could have contributed to lung disease among respondents in one study. "OSHA did recognize and account for the weaknesses of the two studies it relied on here," the judges said.
Celeste Monforton, a lecturer in public health at Texas State University and former OSHA project director, told Courthouse News that the rule had been stalled for years. She said it was complicated by a medical protection provision.
"Medical provisions are the ones that are the most costly and most difficult to actually demonstrate a benefit for," she said. When OSHA factors in those costs, she said, those provisions tend to be the most expensive for the industry.
In remanding the case to OSHA, the DC Circuit said the agency will have to sort out costs for those workers who are pulled off sites for medical reasons.