In April, media reports drew attention to the deaths of nine workers involved in manual tank gauging, sampling, and fluid transfer at oil and gas extraction sites. In all nine cases, which occurred at crude oil productio​n tanks during the period 2010–2014, the inhalation of volatile petroleum hydrocarbons is considered a possible contributing factor. Information from various sources on these fatalities and reported exposures at other sites appears below. All nine victims were either working alone or not being observed at the time of death. In each instance, hydrogen sulfide exposure was ruled out as a possible cause. Four of the fatalities occurred during tank gauging, a task in which workers determine fluid levels by inserting gauges through hatches in the tops of tanks. Due to the tanks’ internal pressure, opening a hatch can release a plume of hydrocarbon gases. These gases can contain benzene, a carcinogen, as well as ethane, propane, and butane. NIOSH investigators have determined that concentrations of these hydrocarbons can exceed immediately dangerous to life or health (IDLH) levels near open tank hatches.

To limit worker exposures to hydrocarbons, NIOSH recommends that oil and gas extraction companies implement technology that allows remote monitoring of tank fluid levels. If remote monitoring isn’t feasible, use of respiratory protection may be required, including a self-contained breathing apparatus (SCBA). NIOSH warns that air-purifying respirators will not protect workers from exposures to certain hydrocarbons and do not protect workers in oxygen-deficient atmospheres.