US Chemical Safety Board Faults Pemex in 2024 Fatal Accident

Lack of standardized equipment identification system led to deadly hydrogen sulfide release at Deer Park refinery.

Published on Feb. 24, 2026

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The U.S. Chemical Safety and Hazard Investigation Board (CSB) released a report on Monday that found the lack of a standard system for correctly identifying idled equipment at Pemex's Deer Park, Texas refinery led to a 2024 incident where a poison gas release killed two workers. The report said workers were preparing an idled, de-inventoried unit for upcoming work when they opened a flange on a nearby pipe of an operating unit, releasing 27,000 pounds of deadly hydrogen sulfide.

Why it matters

The CSB report highlights the importance of clear safety protocols and equipment identification systems at industrial facilities to prevent tragic accidents. The Pemex refinery incident resulted in two fatalities and required shelter-in-place orders in nearby communities due to the dangerous gas release.

The details

According to the CSB report, on October 10, 2024, workers at the Pemex Deer Park refinery were preparing an idled, de-inventoried unit for upcoming work. However, they mistakenly opened a flange on a nearby pipe of an operating unit, releasing 27,000 pounds of deadly hydrogen sulfide. One worker who opened the flange was killed, and as the gas drifted downwind, it overcame another worker who was unable to escape and he also died. Thirteen other workers were taken to medical facilities for evaluation.

  • The incident occurred on October 10, 2024.
  • The CSB report was released on February 23, 2026.

The players

Pemex

The Mexican state-owned petroleum company that operates the Deer Park, Texas refinery where the fatal incident occurred.

U.S. Chemical Safety and Hazard Investigation Board (CSB)

The independent federal agency that investigated the 2024 fatal accident at the Pemex Deer Park refinery and issued the report.

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What’s next

Since the release, the Pemex refinery has adopted a system for identifying equipment to be opened for work, according to the CSB report.

The takeaway

This incident underscores the critical need for industrial facilities to have robust safety protocols and standardized equipment identification systems in place to prevent catastrophic accidents and protect worker and community safety.