Have you experienced the distinctive “rotten egg” smell of a hazardous gas called hydrogen sulfide (H2S)? Occurring naturally from organic decay, for example, around sewage plants, H2S can be found in crude petroleum and natural gas — often in very high concentrations.

A 57-year-old trucker with five children was found by fellow oil workers slumped over dead next to a tank hatch at an oil well near Ardmore, Okla., on March 20, 2014

Workers operating in high-risk industries, such as oil and natural gas and chemical, encounter environments rich with hazardous gases that may be unseen or unfamiliar, such as hydrogen sulfide (H2S).

On May 19th, 2014, NIOSH posted a Science blog titled “Reports of Worker Fatalities during Flowback Operations.” This blog post provided information that NIOSH received from several sources indicating that acute exposures to hydrocarbon gas and vapors likely played a role in the deaths of at least four workers in the oil and gas extraction industry.