The National Institute for Occupational Safety and Health blogged yesterday about reports of worker fatalities during oil and gas extraction flowback operations. Flowback refers to process fluids from the wellbore that return to the surface and are collected after hydraulic fracturing (fracking) is completed.

According to information collected by NIOSH, at least four workers have died since 2010 from what appeared to be acute chemical exposures during flowback operations. While these investigations are not complete, available information suggests to NIOSH that these cases involved workers who were gauging flowback or production tanks, or were involved in transferring flowback fluids at the well site. These fatalities, NIOSH believes, occurred when the workers were performing their duties alone.

NIOSH indicated that hydrogen sulfide (sour gas) “is well recognized as a toxic exposure hazard associated with oil and gas extraction and production.” “However, less recognized by many employers and workers is that many of the chemicals found in volatile hydrocarbons are acutely toxic at high concentrations.” NIOSH conducted exposure assessments to identify chemical hazards to workers involved in flowback operations, and indicated that the initial field studies “suggest that certain flowback operations/activities can result in elevated concentrations of volatile hydrocarbons in the work environment that could be acute exposure hazards.”

NIOSH, through its blog, has requested information and assistance from oil and gas stakeholders to further characterize risks for chemical exposures during flowback fracking operations and, as needed, to develop and implement exposure controls.

Employers in these industries should take note of these investigations and concerns. With these in mind, review your company’s safety policies and training materials and programs to ensure your employees are familiar with all such hazards. You may be sure that an OSHA inspector, should one visit, will be looking for those things as well.