Workers at hydraulic fracturing – fracking – oil and gas sites are routinely exposed to high levels of benzene, according to a study by the National Institute for Occupational Safety and Health (NIOSH).
The agency, part of the Centers for Disease Control and Prevention (CDC), recommends that workers limit their benzene exposure to an average of 0.1 of a part per million during their shift. But when the researchers measured airborne benzene workers would be exposed to when they opened hatches on tanks at well sites, 15 of 17 samples exceeded that amount, the Los Angeles Times reports. Benzene levels at the wells “reached concentrations that, depending on the length of exposure, potentially pose health risks for workers,” the researchers wrote in the Journal of Occupational and Environmental Hygiene. Workers must open the hatches one to four times per hour to inspect and measure the contents.
Benzene, a component of crude oil, “can be acutely toxic to the nervous system, liver, and kidneys at high concentrations,” according to the study. The CDC explains that benzene interferes with the normal workings of cells and “can cause bone marrow not to produce enough red blood cells, which can lead to anemia.” Benzene can also damage the immune system.
In 2013, NIOSH took air measurements over two-day periods at six oil and gas sites in Colorado and Wyoming, according to the Times. Sixteen workers at each site wore devices attached to their shirt collars that sampled the air throughout the day. Workers breath in the fumes for two to five minutes each time they open the hatch to measure the flowback tanks’ contents. They do this up to four times an hour in a 12-hour shift, exposing them to volatile organic compounds from the chemicals used in fracking or from the hydrocarbons themselves, according to the Times.
Little is known about the long-term effects of benzene exposure on oil and gas workers, the Times reports. Dr. Robert Harrison, director of Occupational Health Services at UC San Francisco said the risks posed by benzene are ones “that we would want to pay attention to.”