---
title: "CSB Final Report"
description: "CBRNe World provides those tasked with defending against CBRN and IED threats with the essential practical, scientific and political information. Access the current and previous issues of the magazine by registering as a member."
url: "https://cbrneworld.com/threats-news/americas/csb-final-report"
date: "2026-07-30T21:07:02+00:00"
language: "en-GB"
---

#  CSB Final Report

 Written on 25 February 2026.

The US Chemical Safety and Hazard Investigation Board (CSB) has released its final investigation report into the fatal chemical release at a Texas-based refinery in 2024.

Two contract workers died of exposure to toxic hydrogen sulphide gas in the Oct. 10, 2024, chemical release at the Pemex Deer Park Refinery in Deer Park, TX.. Meanwhile, 13 other workers were transported to local medical facilities, and dozens more were treated at the scene.

More than 27,000 pounds of toxic hydrogen sulphide gas were released during the incident, and a shelter-in-place order was issued for two neighbouring cities, according to the report. One Repcon worker was fatally injured when the gas was released. The hydrogen sulphide vapor travelled downwind into an adjacent unit, where a worker employed by another contractor (ISC) inhaled the toxic gas and was also fatally injured. The release continued for nearly one hour until refinery emergency responders reassembled the leaking flange and stopped the discharge. Because of the release, local officials in the neighboring cities of Deer Park and Pasadena, TX, issued shelter-in-place orders that remained in effect for several hours.

The report concludes that the incident resulted from the failure to positively identify the correct equipment before mistakenly opening the piping that contained hydrogen sulfide instead of the piping that had been clear of the toxic gas.

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