Silica exposures in fracking : Over 60 percent of workers may be excessively exposed

At least 1.7 million US workers are exposed to respirable crystalline silica each year, this according to the National Institute for Occupational Safety and Health (NIOSH). These exposures occur in a variety of industries, among them construction, sandblasting, mining, masonry,  stone and quarry work, and in the rapidly expanding method of oil and gas extraction known as hydraulic fracturing or fracking. This exposure can lead to silicosis,  an irreversible, and sometimes fatal, lung disease that is only caused by inhaling respirable silica dust. Silica exposure also puts exposed workers at risk of lung cancer, pulmonary tuberculosis and other respiratory diseases. It is also associated with autoimmune disorders, chronic kidney disease and other adverse health effects. As big a number as 1.7 million is (about 200,000 more people than currently live in Philadelphia), the “true extent of the problem is probably greater than indicated by available data,” according to NIOSH. The CDC agency has also written, there  “are no surveillance data in the US that permit us to estimate accurately the number of individuals with silicosis.”

It is against this backdrop of ongoing exposures of nearly 2 million silica-exposed workers and the serious health effects, that the Occupational Safety and Health Administration (OSHA) has proposed a regulation to address the hazard.  One provision of the proposal would update the agency’s permissible exposure limits for respirable crystalline silica for the first time in forty years. The new standard, which includes a more protective exposure limit, has been in development for more than ten years. Last month – responding to requests from industry groups that include oil and gas and industrial sand producers – OSHA extended by  45 days the public comment period on the proposed changes. What OSHA is proposing would effectively drop by half the allowable exposure limit and it estimates, will “save nearly 700 lives and prevent 1,600 new cases of silicosis per year once the full effects of the rule are realized.”

Almost certainly undercounted in these estimates is the extent of workers exposed to respirable crystalline silica in hydraulic fracturing operations. As I’ve reported previously for The Pump Handle, respirable silica has recently been recognized as a hazard in fracking operations, which can use between several tons to two million pounds of industrial sand per well site. Last year, NIOSH and the Occupational Safety and Health Administration (OSHA) issued a hazard alert for silica after a NIOSH field study conducted in 2010 and 2011, and released in 2012, found excessive exposure to silica at 11 sites in five states.

These findings were summarized by the researchers in a recent article in Well Servicing Magazine where they explain that the majority of exposures for employees involved working around sand movers (74%), sand transfer belts (83%) and what are called blenders (50%) were above the 40 year old OSHA exposure limits. They also explained that excessive exposures were also documented for employees working upwind but not in the immediate area of sand moving equipment as well as for employees inside truck cabs that did not have fine particulate filters or tight-sealing doors. Not included in this documentation is the number of workers at these 11 worksites affected by these exposures.

An industry-wide problem

Exposure to respirable silica through use of the industrial sand used as proppants in fracking  – the tiny grains prop open the fissures in the rock, allowing oil and gas to flow  – is an industry-wide problem. The oil and gas industry has established a Respirable Crystalline Silica Focus Group as part of is “National STEPS Network” that is being coordinated by the American Petroleum Institute. This voluntary effort’s goal is to “expand the information on workplace exposures to respirable crystalline silica from hydraulic fracturing by collecting data within the industry” and “to further characterize the factors affecting exposures during hydraulic fracturing.” The industry group has been discussing how to address this issue. According to the minutes from the September meeting of the network’s Respirable Silica Task Force, Assistant Secretary of Labor for OSHA David Michaels told the group that OSHA estimates that roughly 25,000 workers in 444 establishments in hydraulic fracturing would benefit from OSHA’s proposed new silica exposure standard. He added that over 60% of these workers in hydraulic fracturing are exposed to silica above OSHA’s proposed permissible exposure limit (PEL). These exposures are also likely taking place across a wide geography. According to a report from Environment America released last month, fracking operations are now underway in 17 states and more than 22,326 hydraulic fracturing wells were drilled or permitted in 2012.

NIOSH has made recommendations for actions that will reduce these harmful exposures and the industry has also developed a list of best management practices. The roster of oil and gas industry company representatives participating in the voluntary respirable silica effort is extensive but at this point, publicly available information does not indicate which companies may have taken such steps or even which companies are responsible for implementing and overseeing this activity. Moreover, OSHA has not updated its on-line chemical health exposure database since 2011 so recent information about where OSHA may have found excessive silica exposures violations since 2009 is not available. The oil and gas industry workers who would be at well sites when frac sand is delivered and deployed are largely unrepresented by any labor unions so it is hard to know from an employee perspective how these workers may be informed about these and other workplace health hazards.

Information gaps persist

In hopes of filling some of these information gaps, I filed a FOIA with NIOSH in June 2012.  I asked for the names of the companies where NIOSH had done its silica exposure field study and where exactly this sampling had been done. On November 8, 2013, I received a reply: 178 pages on which every bit of information that could identify a company or business by name. or geographic location of the fracking site has been redacted. The CDC (the agency under which NIOSH works) sent copious documentation of its sampling work, including handwritten notes and photographs. But even on photographs, any logo or company name has been whited-out. Citing provisions of the Freedom of Information Act, the CDC says it is withholding this information (including more than 100 pages in their entirety) because it is confidential or otherwise privileged or private. To release it, wrote the CDC, would cause competitive disadvantage, interfere with the agency’s deliberative process or be an unwarranted invasion of privacy. Although my FOIA request did ask for names of businesses it did not ask for any information that would identify individuals.

So the overarching question remains, how does withholding from the public the names of companies whose operations exceeded existing silica exposure standards advance occupational health protection? As NIOSH has written, “People only get silicosis from inhaling respirable crystalline silica dust into their lungs. Thus, every case represents failure to prevent excessive exposure.”

Elizabeth Grossman is the author of Chasing Molecules: Poisonous Products, Human Health, and the Promise of Green ChemistryHigh Tech Trash: Digital Devices, Hidden Toxics, and Human Health, and other books. Her work has appeared in a variety of publications including Scientific American, Yale e360, Environmental Health Perspectives,, The Washington Post, Salon and The Nation. 











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