CSB Safety Video: Silent Killer - Hydrogen Sulfide Release in Odessa, Texas

U.S. Chemical Safety Board (CSB), August 20, 2021

The U.S. Chemical Safety Board (CSB) has released an animation detailing the events leading up to the October 26, 2019, hydrogen sulfide (H2S) release at the Aghorn Operating waterflood station in Odessa, Texas. The release fatally injured an Aghorn employee who was working at the facility that evening, as well as his spouse who attempted to locate him at the facility after he did not return home.

In the video CSB Chairperson and CEO, Dr. Katherine Lemos says, “We urge companies operating oil and gas facilities to understand the findings from this investigation and implement appropriate safeguards and training. We need to work together to ensure that our workers and community members return home safely each and every day.

The CSB's investigation identified six serious safety issues that led to the deadly incident:

  1. Nonuse of Personal H2S Detector. The pumper fatally injured in the release was not wearing his personal H2S detection device the night of the incident, and there is no evidence that Aghorn management required the use of these devices.
  2. Nonperformance of Lockout / Tagout. At the time of the incident, Aghorn did not have any well-documented Lockout / Tagout policies or procedures. The pumper fatally injured did not perform Lockout / Tagout to deenergize Pump #1 before performing work on it, and the automatic activation of the pump allowed water containing H2S to release from the pump.
  3. Confinement of H2S Inside Pump House. The pump house ventilation methods did not adequately ventilate the toxic H2S gas from the building during the incident, contributing to the high H2S levels to which the two individuals fatally injured were exposed.
  4. Lack of Safety Management Program. Aghorn did not have adequate company safety or operational policies or procedures in place at the time of the incident.
  5. Nonfunctioning H2S Detection and Alarm System. The pump house was equipped with an H2S detection and alarm system. However, the H2S control panel did not receive signals from the internal and external detection sensors at the facility, and, therefore, did not trigger either of the two H2S alarms on the night of the incident.
  6. Deficient Site Security. As per Aghorn’s informal policy, when an Aghorn employee is working at the facility, the access gates are normally left unlocked. The unlocked gates allowed the pumper's spouse to drive directly to the waterflood station and enter the pump house, where she was exposed to toxic H2S gas and fatally injured.

To prevent future chemical incidents, and in the interest of driving chemical safety change to protect people and the environment, the CSB made seven recommendations to Aghorn Operating, Inc. (and similar companies) for safety improvements at all waterflood stations where the potential exposure to dangerous levels of toxic hydrogen sulfide gas exists. 

The CSB also made two recommendations to federal and state regulators, OSHA and the Railroad Commission of Texas, addressing the requirements for protecting workers from hazardous air contaminants and from hazardous energy.

Chairman Lemos concludes by saying, “This tragic accident did not need to happen. This is a call to action for all companies, large and small, to step up to the plate to prioritize the safety of your workers and your community.



About the CSB

The CSB is an independent, non-regulatory federal agency whose mission is to drive chemical safety change through independent investigations to protect people and the environment. The agency’s board members are appointed by the President and confirmed by the Senate. CSB investigations look into all aspects of chemical incidents, including physical causes such as equipment failure as well as inadequacies in regulations, industry standards, and safety management systems. For more information, visit or contact Communications Manager Hillary Cohen at or by phone at (202) 446-8094.

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Posted by Kishorsing Rajput on February 10, 2023
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