In February, NIOSH and OSHA issued a joint hazard alert on protecting oil and gas workers who manually gauge or sample fluids on production and flowback tanks from exposure to hydrocarbon gases and vapors (HGVs), exposure to oxygen-deficient atmospheres, and the potential for fires and explosions. The alert discusses how opening tank hatches, or “thief hatches,” can release high concentrations of HGVs. These exposures can cause immediate health effects in workers, including loss of consciousness and death. Oil and gas production tanks may contain HGVs that are under pressure, which can displace oxygen when the thief hatch is opened, creating an oxygen-deficient environment. Also described in the hazard alert is the potential for fires and explosions if HGV concentrations exceed 10 percent of the lower explosive limit. The alert follows a recent report identifying nine deaths of oil and gas workers between January 2010 and March 2015 in which exposure to HGVs was confirmed or suspected. The new alert includes several recommendations for employers regarding manual tank gauging and fluid sample collection that cover engineering controls, work practices, and personal protective equipment. NIOSH and OSHA encourage employers to implement alternative procedures that allow workers to perform tank gauging and sampling without opening the tank hatch; ensure that workers correctly and consistently use calibrated multi-gas and oxygen monitors; and install thief hatch pressure indicators to provide an immediate visual indicator of potential hazards. The full list of recommendations is available in the hazard alert on NIOSH’s website.