Today, the U.S. Chemical Safety and Hazard Investigation Board (CSB) released an update on the agency’s investigation of a fatal release of toxic hydrogen sulfide gas at the PEMEX Deer Park Refinery in Texas on October 10, 2024, which killed two workers and injured 13 others. PLEASE UNDERSTAND we may know WHAT happened, but we still do NOT know HOW or WHY it happened.
During a maintenance activity at 4:23 p.m., approximately 27,000 pounds of toxic hydrogen sulfide gas were released. In addition to the two fatalities and other serious injuries, the release resulted in shelter-in-place orders issued by officials in the nearby cities of Deer Park and Pasadena, Texas, lasting for several hours, and a portion of Texas State Highway 225 was closed temporarily.
The CSB’s update states that on the day of the incident, two (2) contract workers at the refinery partially opened a flanged connection on piping containing hydrogen sulfide gas, which caused the release. One of these workers was fatally injured. The work was supposed to be done on a different, isolated piping segment located about five feet away from the flange that was opened. Two other contract workers from a separate company, who were working on equipment less than 250 feet away and downwind from the release, were also affected, with one fatally injured from the hydrogen sulfide exposure.