Hidden Risks for Oil and Gas Workers

“Exposure to high concentrations of hydrocarbon gasses and vapors (HGV) and oxygen-deficient atmospheres during manual tank gauging and sampling can pose a risk for sudden cardiac death,” according to a new report.

“Although the first two deaths described in this series were not immediately recognized as work-related, the occurrence of seven additional deaths under similar circumstances suggests that HGV exposure during manual tank gauging and sampling can be life-threatening.”

Workers in oil and gas extraction are known to have high rates of traumatic work-related fatalities, more than seven times the national average, according to government researchers. They’ve now found that sudden deaths among the workers may result from oxygen deficiency and inhalation of HGVs.

Of the nine deaths, all had been working alone and were found collapsed on a tank or catwalk or at the base of the catwalk stairs.

An analysis of nine deaths among such workers from 2010 through March 2015 found similar characteristics among them all. “The suspected cause of these deaths was exposure to HGVs and oxygen-deficient atmospheres after opening the hatches of hydrocarbon storage tanks,” according to the National Institute for Occupational Safety and Health. “Recommendations were made to industry and regulators regarding the hazards associated with opening hatches of tanks, and controls to reduce or eliminate the potential for HGV exposure were proposed.”

Workers at these sites “often manually gauge the level of fluid or collect a sample from storage tanks containing process fluids,” the agency explained. “These workers climb to the top of the tanks, open a “thief” hatch (a closable aperture on atmospheric tanks, used to sample the tank contents) and either place a device into the hatch to measure the fluid level or lower a ‘thief’ sampler (a hollow tube) into the tank to collect liquid samples.”

Solo Workers Vulnerable

Of the nine deaths, all had been working alone and were found collapsed on a tank or catwalk or at the base of the catwalk stairs. NIOSH said at least five of the victims were found with the hatch open.

Five of the deaths occurred during the collection of a fluid sample, and four occurred during tank gauging. However, toxicologic data on HGVs were not consistently collected during autopsy, but petroleum hydrocarbon vapors had been noted as a cause of death for three workers.

Additionally, just one of the victims appeared to be wearing a respirator, although a fit test had not been conducted and the respirator was insufficient for high concentrations of HGVs or oxygen deficiency.

The report is one of the few that addresses chemical exposures and acute occupational illness associated with oil and gas extraction, the researchers said. The results have implications for employers, workers, and others.

“Health care professionals who treat or evaluate oil and gas workers need to be aware that workers might report symptoms of exposure to high concentrations of HGVs and possible oxygen deficiency; employers and workers need to be aware of this hazard and know how to limit exposure,” the researchers noted. “Medical examiners investigating the deaths of oil and gas workers who open tank hatches should consider the contribution of oxygen deficiency and HGV exposure.”