The fact that microscopic asbestos fibers caused mesothelioma and asbestos-lung cancer may have come as a shock generations ago, but scientists and safety regulators have known for decades that other airborne particulates carry the same risk. With substantial profits to be gained through the use of these products, however, there continues to be resistance to regulation — or even to appropriate safety measures being taken.
As we discussed on this blog in April, another particulate that could cause mesothelioma or lung cancer similar to that caused by asbestos is taconite, an iron-bearing sedimentary rock mined for usable iron ore. Only last month, the National Institute for Occupational Safety and Health released guidelines on protecting workers from the potential risks of working with engineered nanomaterials — materials far less than the width of an eyelash in at least one dimension. Asbestos was in the minds of NIOSH scientists as they wondered about the potential for lung cancer or other inflammatory diseases airborne nanomaterials might cause.
Now, a study of more than 30,000 pottery and tin workers in China who were regularly exposed to crystalline silica dust over a 44-year period found a link to that exposure and an increased risk of lung cancer. This isn’t exactly a surprise — the International Agency for Research on Cancer has already classified crystalline silica as a human carcinogen.
“These findings confirm silica as a human carcinogen,” the researchers said, “and suggest that current exposure limits in many countries might be insufficient to protect workers from lung cancer.”
Unfortunately, cigarette smoking appeared to compound the effect of silica dust exposure, but the rate of lung cancer among the exposed workers was still higher than that among non-exposed tobacco users.
The study was just published in the American Journal of Epidemiology — just as the Occupational Safety and Health Administration considers a new rule to require greater safety steps for workers exposed to airborne crystalline silica. Inhalation of even small particles of the substance, OSHA says, can lead to silicosis, chronic obstructive pulmonary disease, lung cancer, and kidney disease.
OSHA has said that nearly 700 people’s lives could be saved and 1,600 people would be saved from getting silicosis if the new rule is fully put into place. Unfortunately, construction, shipbuilding and other industries have thus far failed to put consistent worker safety standards in place, and “do not adequately protect worker health,” OSHA says.
Source: R&I magazine’s WorkersComp Forum, “Study said to confirm that silica is a human carcinogen,” Nancy Grover, Dec. 2, 2013