US confirms high chemical exposures in fracking

Workers in the fracking industry are exposed to high levels of dangerous chemicals including cancer-causing benzene, an official study has found. The US government’s occupational health research body NIOSH found technicians working over the flowback tanks were routinely exposed to benzene at above its recommended exposure limit.

Workers in the fracking industry are exposed to high levels of dangerous chemicals including cancer-causing benzene, an official US study has found.

The US government’s occupational health research body NIOSH evaluated worker exposures to chemicals during oil and gas extraction flowback and production testing activities. These activities are necessary to bring the well into production. Flowback refers to process fluids that return from the well bore and are collected on the surface after hydraulic fracturing (fracking).

In addition to the mixture originally injected, returning process fluids can contain a number of naturally occurring materials originating from within the earth, including hydrocarbons such as benzene. NIOSH had earlier linked a series of deaths to chemical exposures from flowback operations.

In the latest investigation, metabolites of benzene were found in the urine of fracking workers. The researchers also found technicians working over the flowback tanks were routinely exposed to benzene at above the NIOSH recommended exposure limit.
They noted: “Task-based personal breathing zone samples for benzene collected during tank gauging on flowback tanks exceeded the NIOSH short-term exposure limit (STEL) for benzene (1 ppm as a 15-minute TWA). At several sites, direct-reading instrumentation measurements detected peak benzene concentrations at open hatches exceeding 200 ppm.”

NIOSH concluded “that airborne concentrations of hydrocarbons, in general, and benzene, specifically, varied considerably during flowback and can be unpredictable, indicating that a conservative approach to protecting workers from exposure is warranted. Hydrocarbon emissions during flowback operations also showed the potential to generate flammable and explosive concentrations depending on time and where measurements were made, and the volume of hydrocarbon emissions produced.”

The US government body recommended changing work methods, providing improved training, limiting “the time spent in proximity to hydrocarbon sources” and provision of appropriate respiratory protection and impermeable gloves.