Introduction to the Incident
The U.S. Chemical Safety and Hazard Investigation Board (CSB) has released an update on the investigation into the October gas leak at the PEMEX Deer Park facility. This incident resulted in the death of two contract workers due to hydrogen sulfide poisoning. The workers were in two separate locations approximately 250 feet apart. One collapsed immediately, and the other died while trying to escape.
Cause of the Leak
According to the CSB update, 27,000 pounds of hydrogen sulfide were released because two contract workers opened the wrong flange due to a misplaced identification tag. The investigation found that two pipes, one that had been depressurized and isolated for work and another that was pressurized with toxic gas, were only 5 feet apart. The workers, unaware of the correct pipe, opened the pressurized one, leading to the massive leak.
Details of the Incident
The two workers who died were boilermakers contracted by PEMEX Deer Park to work on 15 blinds, which are used to isolate sections of pipes. They were working at the Amine Regeneration Units, while two other contract workers with ISC were working at a different location, the Sulfur Recovery Unit. The boilermakers opened the pressurized piping, believing it was the unpressurized blind, and wore supplied-air respirators without personal hydrogen sulfide gas detectors. They may have been unaware of the hydrogen sulfide leak until it was too late.
Sequence of Events
At 4:23 p.m., the connection was disassembled enough that the flange opened, forcefully releasing toxic hydrogen sulfide gas. Following the leak, the two boilermakers disconnected their supplied air connections and began to flee. One died near the top of the ladder, and the other fled via the primary assembly point. The leaked hydrogen sulfide was carried by the wind toward the Sulfur Recovery Unit, where the two ISC workers were, and the sulfide detectors were disabled.
Aftermath and Response
The incident resulted in 13 contractors being taken to the hospital to be evaluated for hydrogen sulfide exposure. The CSB investigation is ongoing, and the agency will continue to review the incident. Possible recommendations will be released once the investigation is completed. PEMEX, ISC, and Repcon did not immediately respond to requests for comment.
Conclusion
The incident at the PEMEX Deer Park facility highlights the importance of proper safety protocols and accurate identification of equipment in industrial settings. The misplaced identification tag and the failure to use personal hydrogen sulfide gas detectors contributed to the tragic outcome. As the investigation continues, it is crucial for industries to learn from this incident and implement measures to prevent such accidents in the future, ensuring a safer working environment for all employees.
