A recent study by the National Institute for Occupational Safety and Health (NIOSH) has found that workers at hydraulic fracturing or fracking sites may be routinely exposed to dangerous levels of the cancer-causing chemical benzene.
Benzene is a clear or light yellow liquid that is a component in fracking fluid. NIOSH and the Centers for Disease Control and Prevention have set the safe level for workplace benzene exposure at 0.1 of a part per million. However, NIOSH’s measurements of benzene levels above open tanks at fracking sites found levels that were well over this amount.
NIOSH researchers visited six oil and gas sites in Colorado and Wyoming in the spring and summer of 2013. The study specifically surveyed exposure risks for oil and gas workers during the phase of extraction called flowback. This phase occurs after the well is drilled and hydraulically fractured to start the flow of oil and gas. Flowback fluid which contains wastewater, sand, oil, gas, fracking fluid chemicals and water is recovered through the well bore and separated into component parts. Oil and gas are removed and stored in production tanks. Fracking chemicals that can be reused are also removed the fluid. Waste fluids are stored in flowback tanks until they can be disposed of.
Fracking-site workers must inspect and measure the volume of liquids in flowback and production tanks. To do this, they must open the hatches and insert a gauging stick. If the well is very deep, a worker may use a hand-cranked gauging tape to make the measurements. It is during this phase that workers are at highest risk of exposure to dangerous levels of benzene.
Sixteen fracking workers were provided with small, wearable devices that sampled the air during their workday. The study participants typically worked 12 hour days. During this time, they opened up the hatches one to four times an hour. The hatch was open for two to five minutes at a time.
Air samples showed this was enough to add up to dangerous levels of exposure to oil, gas, and the volatile organic compounds used in fracking. However, the researchers were primarily concerned about Benzene because benzene interferes with the normal functioning of cells. High concentrations of the chemical are toxic to the nervous system, liver, and kidneys. Benzene can also cause bone marrow to reduce the production of red blood cells and white blood cells, which can lead to anemia and damage to the immune system. Benzene is also a carcinogen that is linked to leukemia.
All except two of the samples recorded average daily benzene exposure above the NIOSH limit. The average benzene exposure also exceeded the higher limit of 1 part per million set by the federal Occupational Safety and Health Administration (OSHA). OSHA limits are legal workplace limits and tend to be higher than the limits set by NIOSH and the CDC. Little is known about the long-term effects of benzene exposure.
The study was published in the September 2014 issue of the Journal of Occupational and Environmental Hygiene. NIOSH’s research on benzene is part of an ongoing study to assess chemical exposure risks for oil and gas workers involved in fracking and flowback operations.
The study recommended that workers wear respirators when measuring flowback volume in order to decrease chemical exposure. oil and gas companies use other techniques to measure flowback volume so they can limit workers’ exposure to chemicals in the air around the flowback tanks