NIOSH Exposure Assessments in the Upstream Oil and Gas Industry: Exposures during Flowback and Production Testing Operations

NIOSH initiated the Field Effort to Assess Chemical Exposures in Oil and Gas Workersto determine if chemical exposure risks were present for workers during drilling, completions and servicing operations. This presentation describes continuing industrial hygiene field research focusing on exposure risks for hydrocarbons including benzene, toluene, ethyl benzene and xylenes (BTEX) and other chemicals associated with flowback and production testing operations.  A variety of exposure assessment techniques (personal and area air sampling) were conducted at a number of oil and gas well sites using integrated industrial hygiene sampling and real-time detection methods for chemicals including hydrocarbons such as BTEX, alcohols, glutaraldehyde, polyaromatics, and respirable crystalline silica.  Preliminary study results suggest that inhalation risks for hydrocarbon exposures are present for workers who gauged flowback and production tanks, with average concentrations of benzene 2.5 times that of the NIOSH full-shift recommended exposure level (REL). Pre and post-shift biological monitoring of workers for benzene was also performed; however, sample results were below the American Conference of Governmental Industrial Hygienists’ (ACGIH) Biological Exposure Index (BEI). Real-time monitoring identified instances of high concentrations of total volatile organic compounds (VOCs) above 10% of the lower explosive limit (LEL) prompting concerns for flammability/explosivity and acute toxicity hazards. Initial NIOSH research identified exposures of concern for total VOCs and benzene, in particular, for workers involved in manually gauging flowback and production tanks at oil and gas well sites. Considerations for controls will be briefly discussed.