FATALFacts No. 18 – 2023

Hydrogen Sulfide Release U.S. Department of Labor Occupational Safety and Health Administration www.osha.gov • (800) 321-OSHA (6742)

BRIEF DESCRIPTION OF INCIDENT* A worker died of acute hydrogen sulfide (H2S) poisoning while responding to an alarming water pump involved in the process of

Photo: U.S. Chemical Safety and Hazard Investigation Board extracting crude oil and natural gas. The worker was alone in the pump house attempting to close process valves to isolate the pump. Either before the worker’s arrival or during his work, the pump unexpectedly energized, releasing water containing H2S gas into the pump house. H2S monitors in and around the building were not functioning, and the worker was not wearing a personal H2S gas detector. The H2S concentration reached fatal levels killing the worker. A few hours later, out of concern that she had not heard from her husband in a while, the worker’s spouse entered the facility and died from H2S poisoning. Emergency responders noted they could smell H2S as soon as they entered the facility. As they approached the pump house, the smell of H2S was overwhelming even though the pump houses’ bay doors were partially open and there were no H2S alarms. H2S is a colorless, flammable, and LIKELY CAUSES corrosive gas with an odor similar to The employer knew about the potential H2S exposure hazard, but did rotten eggs. People can lose their ability not establish and enforce a formal policy requiring employees to wear to smell H2S, even at low concentrations, personal H2S detectors while in the pump house or adhere to OSHA’s a condition called olfactory fatigue. standard on air contaminants, 29 CFR 1910.1000. Because of olfactory fatigue, OSHA Although the facility had been equipped with multiple H2S detection warns that the sense of smell should and alarm systems, none of the detectors communicated with the not be used as a detection method. system’s control panel. Some detectors had been set to a testing According to the National Institute for mode, preventing any alarm signals from being sent by any of those Occupational Safety and Health (NIOSH), detectors to the alarm control panel. Other detectors that were H2S environmental concentrations of 100 correctly set up were also unable to send a signal to the control room. The employer supplied personal H2S gas detectors, which would have ppm are immediately dangerous to life notified the worker of the potential exposure with an audible alarm, or health, concentrations greater than but they did not have formal written policies requiring their use. 500 ppm can cause a person to collapse within five minutes, and concentrations The following contributed to the deaths. The employer: exceeding 700 ppm can cause immediate • Failed to maintain and properly configure the H2S detection and collapse, and death, within just one or alarm system. two breaths. The OSHA permissible • Failed to enforce operator use of personal H2S detectors when in the exposure limit (PEL) for H2S is 20 ppm vicinity of equipment or facilities with the potential for an H2S release. (29 CFR 1910.1000 Table Z-2) and is not to • Failed to develop, train, and enforce lockout/tagout procedures. be exceeded at any time during an 8-hour • Failed to evaluate the ventilation systems of the building to ensure it shift, except if the exposure is 50 ppm was adequately ventilated and in working condition. for no more than 10 minutes in an 8-hour • Lacked a robust safety management program. shift so long as no other measurable • Did not establish procedures prohibiting untrained visitors from exposure occurs. entering processing buildings; which allowed the employee’s spouse to access the facility and her subsequent toxic H2S exposure and death.

* Some of the information in this FatalFacts was obtained from the US Chemical Safety and Hazard Investigation Board Final Investigation Report on Aghorn Operating Waterflood Station Hydrogen Sulfide Release: www.csb.gov/file.aspx?DocumentId=6155.

INCIDENT PREVENTION H2S hazards during oil and gas production activities are generally well YOU HAVE A VOICE known. In this instance, H2S is a known hazard for oil and gas activities IN THE WORKPLACE in the Permian Basin where this facility was located. Employers must The Occupational Safety and Health implement appropriate safeguards against H2S exposure hazards. Act of 1970 (OSH Act) affords workers the right to a safe workplace and the Employers must have engineering and administrative controls right to speak up about hazards without for air contaminants whenever feasible in compliance with 29 fear of retaliation (see OSHA’s Worker CFR 1910.1000(e). When such controls are not feasible to achieve Rights page, www.osha.gov/workers). full compliance, protective equipment or any other protective Workers also have the right to file a safety measures must be used to keep the exposure of employees to air & health complaint with OSHA if they contaminants within the limits of OSHA’s air contaminants standard, believe that there are either violations of 29 CFR 1910.1000. Respirators must comply with NIOSH guidelines OSHA standards or serious workplace for respiratory protection and OSHA’s standard on respiratory hazards. In addition, if workers are protection, 29 CFR 1910.134. Whenever respirators are used, employers retaliated against for exercising their shall ensure that the selected respirators are certified and used in rights under the OSH Act, they may file compliance with their certification conditions in accordance with a whistleblower complaint with OSHA 29 CFR 1910.134(d)(1)(ii). The NIOSH division of National Personal within 30 days of the alleged retaliation. Protective Technology Laboratory (NPPTL) provides a certified equipment list that is regularly updated as respirators are approved, HOW OSHA CAN HELP made obsolete, or the status changes in any way. For questions or to get information or advice, to report an emergency, fatality, Additionally, if the pump had been properly isolated under a lockout/ hospitalization, amputation, or loss of an tagout program, it is less likely the worker would have been exposed eye, or to file a confidential complaint, to such high concentrations of H2S. Employers must have a formalized contact your nearest OSHA office, visit lockout/tagout program to isolate equipment from energy sources. http://www.osha.gov or call our toll-free This program should emphasize energy control procedures, training, number at 1-800-321-OSHA (6742), TTY and periodic inspections in compliance with OSHA’s control of 1-877-889-5627. It’s confidential hazardous energy standard 29 CFR 1910.147.

The US Chemical Safety and Hazard Investigation Board (CSB), an MORE INFORMATION independent federal agency charged with investigating industrial • OSHA standards and regulations: www. chemical accidents, recommend the following to the employer: osha.gov/law-regs • OSHA publications: www.osha.gov/ • Mandate the use of personal H2S detection devices as an integral part publications of every employee or visitor personal protective equipment (PPE) • OSHA-approved state plans: www. kit prior to entering the vicinity of the facility. Ensure detector use osha.gov/stateplans is in accordance with manufacturer specifications. (2020-01-I-TX-1, abbreviated) • OSHA’s free On-site Consultation services: www.osha.gov/consultation • Commission an independent and comprehensive analysis of each facility ventilation design and mitigation systems to ensure that • Training resources: www.osha.gov/ workers are protected from exposure to toxic gas (2020-01-I-TX-3, training abbreviated) • Help for Employers: www.osha.gov/ • Ensure the H2S detection and alarm systems are properly maintained employers and configured and develop site-specific detection and alarm programs and associated procedures based on manufacturer specifications, current codes, standards, and industry good practice guidance (2020-01-I-TX-5, abbreviated).

Employers in the oil and gas production industries should develop and implement a written formal site-specific security program to prevent unknown and unplanned entrance of non-employees to the facility. Site security for petroleum and petrochemical facilities should follow industry standards and guidance such as ANSI/API Standard 780, Security Risk Assessment Methodology for the Petroleum and Petrochemical Industries, and API RP 781, Facility Security Plan Methodology for the Oil and Natural Gas Industries.

ADDITIONAL RESOURCES The following CSB report provides a detailed incident report: Aghorn Investigation Report

The following resources provide additional information on chemical hazards, respiratory protection, H2S, and the control of hazardous energy:

• OSHA Chemical Hazards and Toxic Substances Safety • OSHA Hydrogen Sulfide Safety & Health Topics, Fact and Health Topics Sheet, eTool, and Quick Card • OSHA Respiratory Protection Safety and Health Topics • NIOSH H2S Safety and Health Topics • OSHA Lockout/Tagout Safety & Health Topics, Fact Sheet, • NIOSH National Personal Protective Technology Guidance Booklet, eTool Laboratory (NPPTL) • For the oil and gas extraction industry specifically: • Oil & Gas Well Drilling Common Incidents Asphyxiation – OSHA Safety & Health Topics and eTool • OSHA-NIOSH Hazard Alert: Health and Safety Risks for Workers Involved in Manual Tank Gauging and Sampling at – Harwood Grant Training Materials PowerPoint Oil and Gas Extraction Sites – LOTO OSHA Harwood Grant Training Materials PowerPoint

Note: The described case was selected to increase awareness of the risk discussed and prevent similar fatalities. The incident prevention recommendations do not necessarily reflect the outcome of any legal aspects of this case. OSHA encourages your company or organization to duplicate and share this information.

This Fatal Facts is not an OSHA standard or regulation and it creates no new legal obligations. The recommendations contained herein are advisory in nature and are intended to assist employers in providing safe and healthful workplaces. The Occupational Safety and Health Act of 1970 (OSH Act) requires employers to comply with safety and health standards promulgated by OSHA or by an OSHA-approved state plan. The requirements of OSHA approved state plans can be reviewed by selecting the state’s website at: www.osha.gov/stateplans. The OSH Act’s General Duty Clause, Section 5(a) (1), requires employers to provide employees with a workplace free from recognized hazards likely to cause death or serious physical harm.

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DSG FF-4204 01/2023