Four Fatalities Linked to Used Fracking Fluid Exposure During ‘Flowback,' NIOSH Reports

Daily Environment Report
By Robert Iafolla 

May 19 — Initial government field studies on hydraulic fracturing operations suggest that workers could be exposed to hazardous levels of volatile hydrocarbons from used fracking fluids, the National Institute for Occupational Safety and Health said May 19.

At least four workers have died since 2010, apparently from acute chemical exposures during flowback operations, which involve transferring, storing and measuring fluids that return to the surface after fracking, NIOSH said in a blog post.

The institute assessed worker exposure to other chemicals mixed into fluids that are injected into the earth during fracking, said Max Kiefer, director of NIOSH Western States Office.

 Those findings will be detailed in later publications, including a peer-reviewed case study this summer, Kiefer said.

“But right now, the exposures of concern from a worker standpoint are from endogenous hydrocarbons that can be emitted from returned flowback fluids, not from other chemicals,” Kiefer told Bloomberg BNA May 19.

NIOSH highlighted how little is known about the potential health hazards associated with fracking, such as chemical exposure, in contrast to the well-developed knowledge about safety hazards from accidents common to oil and gas extraction.

Fracking operators mix silica sand and chemicals into water, which is injected underground to fracture shale formations. The liquid mix is removed and the sand remains in the broken shale, acting as a “proppant” to keep the fractures open and allow oil or natural gas to flow. The liquid that flows back can contain volatile hydrocarbons picked up from the shale formations, NIOSH found.

More Study Needed

The institute has studied the health hazards of silica exposure at fracking well pads, but its research thus far into flowback operations is far less comprehensive, Kiefer said.

Researchers would like to look at different types of shale formations, climactic conditions, factors that led to exposure and other variables, he said.

NIOSH asked oil and gas companies and other stakeholders to help further characterize risks associated with flowback operations, as well as to assist with developing and implementing exposure controls as necessary.

Kiefer said reports from media sources and the Occupational Safety and Health Administration about fatalities triggered the research into flowback operations. Some of the fatality investigations are incomplete, but thus far the workers likely were gauging flowback or production tanks, or transferring flowback fluids, NIOSH said in the blog post. The workers, who were located at well sites in the Williston Basin in North Dakota and Montana, often died when working alone.

Risk to a Temporary Workforce

Dan Neal, director of Equality State Policy Center in Wyoming, said health hazards pose a particular risk to fracking workers—known as roughnecks—because the work is temporary, and the worksites are transient.

A roughneck could get sick after work with a company has finished, plus it could be difficult to establish a causal connection between exposure at a particular site and an illness, Neal said. These factors could conspire to make worker compensation impossible to obtain, he said.

“Roughnecks are sort of your ultimate temp worker,” Neal told Bloomberg BNA May 19. “Fracking doesn't fit the traditional employment model, which is what safety and health regulations are built around.”

Moreover, Neal questioned whether health hazards from chemical exposure is something the industry has examined.

Safety and health is important to oil and gas companies  said Shawn Bennett, a spokesman for Energy in Depth, a research and advocacy organization launched by Independent Petroleum Association of America.

Many oil and gas operators and contractors are involved with OSHA in the National Service, Transmission, Exploration and Production Safety Network, which looks for opportunities to improve environmental, safety and health issues, Bennett told Bloomberg BNA May 19.

To contact the reporter on this story: Robert Iafolla in Washington at

To contact the editor responsible for this story: Jim Stimson at

The NIOSH blog post on flowback operations is available at