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Aghorn Operating Inc. Waterflood Station Hydrogen Sulfide Release

Overview

On October 26, 2019, at Aghorn Operating Inc.'s Foster D waterflood station in Odessa, Texas, an employee responded to a pump oil level alarm and attempted to isolate Pump #1 without first performing Lockout / Tagout. The pump automatically turned on and released water containing hydrogen sulfide (H2S) from a broken plunger, fatally exposing the employee. The employee's spouse later entered the facility while searching for him and was also fatally exposed. The CSB identified failures involving personal H2S detector use, Lockout / Tagout, ventilation, H2S detection and alarm system performance, safety management, and site security.

Incident Snapshot

Field Value
Facility / Company Aghorn Operating Inc.
Location Odessa, TX
Incident Date 10/26/2019
Investigation Status The report was released on May 21, 2021. A release of hydrogen sulfide led to the death of one worker as well as a member of the public.
Accident Type Hydrogen sulfide release
Final Report Release Date 05/21/2021

What Happened

  • On October 26, 2019, an Aghorn Operating Inc. employee, Pumper A, responded to a pump oil level alarm at Aghorn’s Foster D waterflood station in Odessa, Texas.
  • In response to the alarm, Pumper A worked to isolate the pump from the process by closing the pump’s discharge valve and partially closing the pump’s suction valve.
  • Pumper A did not first perform Lockout / Tagout to isolate Pump #1 from energy sources before performing work on the pump.
  • At some point on the night of the incident, the pump automatically turned on, and water containing hydrogen sulfide (H2S), a toxic gas, released from the pump.
  • The CSB found post-incident that the pump had a broken plunger from which the water and H2S released.
  • Pumper A was fatally injured from his exposure to the released H2S.
  • Subsequently, the spouse of Pumper A gained access to the waterflood station and searched for Pumper A.
  • During her search efforts, she also was exposed to the released H2S and was fatally injured.

Facility and Process Context

  • The incident occurred at the Foster D waterflood station, operated by Aghorn Operating Inc. in Odessa, Texas.
  • The waterflood station receives produced water, a by-product of oil extraction, from approximately 68 crude oil wells in the Foster Field of the Permian Basin.
  • Produced water is routed to a suction tank and then to the pump house, where positive displacement pumps pressurize the water to approximately 900 pounds per square inch gauge (psig) before it is injected back into the oil reservoir.
  • The pump house could be ventilated by two bay doors on the east side, exhaust fans on the west wall, and natural vents on each of the four outside walls.
  • The pump house was equipped with an H2S detection and alarm system.
  • As per Aghorn’s informal policy, when an Aghorn employee is working at the facility, the access gates are normally left unlocked.

Consequences

  • Fatalities: Pumper A and Pumper A’s spouse were fatally injured.
  • Injuries: None reported.
  • Environmental release: Water containing hydrogen sulfide (H2S) released from Pump #1; produced water and H2S were released from the failed pump.
  • Facility damage: One of the pump's plungers had backed off its threaded connection to the gear end, and the ceramic was shattered. The fragments of the plunger could be seen in the bottom of the cradle.
  • Operational impact: Pump #1 was still running and water was pouring out of the pump’s cradle; the water stopped spilling from the pump after the valve at the bottom of the suction tank was closed.

Key Findings

Immediate Causes

  • Aghorn’s failure to enforce operator use of personal H2S detectors when in the vicinity of equipment or facilities with the potential to release H2S.
  • Aghorn’s failure to develop, train on, and enforce Lockout / Tagout procedures that led to Pumper A performing work on a pump while it was still energized.
  • A component of one of the pumps inside the pump house failed, resulting in the release of produced water containing hydrogen sulfide.
  • The pump automatically turned on and water containing hydrogen sulfide (H2S) was discharged from the pump.

Contributing Factors

  • Aghorn’s facility physical and operational design did not allow for adequate ventilation of the toxic H2S gas inside the pump house.
  • Aghorn’s deficient safety management program.
  • Aghorn’s failure to maintain and properly configure the site H2S detection and alarm system.
  • Aghorn’s poor site security that allowed Pumper A’s spouse to gain access to the facility.
  • Confinement and inadequate ventilation allowed H2S to accumulate to deadly levels inside the pump house.
  • The bay doors were approximately 60% open.
  • The available ventilation methods did not adequately ventilate toxic H2S gas from the building during the incident.
  • The H2S control panel did not receive signals from the internal and external detection sensors at the facility.
  • The alarm system did not incorporate an auditory alert.
  • The access gates were normally left unlocked when an Aghorn employee is working at the facility.
  • Pumper A was not wearing his personal H2S detection device.
  • Pumper A only partially closed the pump’s suction valve.

Organizational and Systemic Factors

  • Aghorn did not have any written Lockout / Tagout policies or procedures.
  • Aghorn had no additional formal company safety or operational policies or procedures.
  • There is no evidence that Aghorn management required the use of personal H2S detection devices.
  • Aghorn’s informal policy left access gates normally unlocked when an Aghorn employee is working at the facility.
  • Aghorn did not have a formal policy requiring employees to wear personal H2S detectors while at waterflood stations.
  • Aghorn did not provide the CSB with sufficient records to determine to what extent Pumper A was trained on the verbal Lockout / Tagout practice.
  • Aghorn did not comply with OSHA regulation 29 CFR 1910.147 – The Control of Hazardous Energy (Lockout / Tagout).
  • Aghorn did not adhere to OSHA regulatory requirement 29 CFR 1910.1000 – Air Contaminants.
  • Aghorn lacked operational, training, testing, and maintenance procedures and records.
  • Aghorn did not maintain or properly configure its Foster D waterflood station facility H2S detection and alarm system.
  • Aghorn’s site security did not meet industry guidance and standards, to include 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.

Failed Safeguards or Barrier Breakdowns

  • Pumper A was not wearing his personal H2S detection device upon entering the waterflood station on the night of the incident.
  • Pumper A did not perform Lockout / Tagout to deenergize Pump #1 before performing work on it.
  • The available ventilation methods did not adequately ventilate toxic H2S gas from the building during the incident.
  • 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.
  • The unlocked gates allowed Pumper A’s spouse to drive directly to the waterflood station and enter the pump house, where she was exposed to toxic H2S gas.
  • The beacon light on top of the pump house was not activated or illuminated.
  • The phone system did not alert Pumper A to the dangerous atmosphere.

Recommendations

  1. 2020-01-I-TX-R1 | Recipient: Aghorn Operating Inc. | Status: Closed – Acceptable Action | For all waterflood stations where the potential exists to expose workers or non-employees to H2S concentrations at or above 10 ppm, mandate the use of personal H2S detection devices as an integral part of every employee or visitor personal protective equipment (PPE) kit prior to entering the vicinity of the facility. Ensure detector use is in accordance with manufacturer specifications.
  2. 2020-01-I-TX-R2 | Recipient: Aghorn Operating Inc. | Status: Closed – Acceptable Action | For all Aghorn facilities, develop a site-specific, formalized and comprehensive Lockout / Tagout program, to include policies, procedures, and training, to protect workers from energized equipment hazards, such as exposure to H2S. Ensure the program meets the requirements outlined in 29 CFR 1910.147 and includes energy control procedures, training, and periodic inspections.
  3. 2020-01-I-TX-R3 | Recipient: Aghorn Operating Inc. | Status: Closed – Acceptable Alternative Action | For all waterflood stations where the potential exists to expose workers to H2S concentrations at or above 10 ppm, commission an independent and comprehensive analysis of each facility design vis-à-vis ventilation and mitigation systems to ensure that, in the event of an accidental release, workers are protected from exposure to toxic gas levels.
  4. 2020-01-I-TX-R4 | Recipient: Aghorn Operating Inc. | Status: Closed – Acceptable Action | For all waterflood stations where the potential exists to expose workers or non-employees to H2S concentrations at or above 10 ppm, develop and demonstrate the use of a safety management program that includes a focus on protecting workers and non-employees from H2S. This program should include risk identification, assessment, mitigation, and monitoring of design, procedures, maintenance and training related to H2S. This program must be in compliance with 29 CFR 1910.1000 – Air Contaminants and 29 CFR 1910.147 – The Control of Hazardous Energy (Lockout / Tagout).
  5. 2020-01-I-TX-R5 | Recipient: Aghorn Operating Inc. | Status: Closed – Acceptable Action | For all waterflood stations where the potential exists to expose workers to H2S concentrations at or above 10 ppm, ensure the H2S detection and alarm systems are properly maintained 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. The program must address installation, calibration, inspection, maintenance, training and routine operations.
  6. 2020-01-I-TX-R6 | Recipient: Aghorn Operating Inc. | Status: Closed – Acceptable Action | For all waterflood stations where the potential exists to expose workers or non-employees within the perimeter of the facility to H2S concentrations at or above 10 ppm, ensure that the H2S detection and alarm system designs employ multiple layers of alerts unique to H2S, such as with the use of both audible and visual mediums, so that workers and non-employees within the perimeter of the facility would be alerted to a significant release. The system design must meet manufacturer specifications, current codes, standards, and industry good practice guidance.
  7. 2020-01-I-TX-R7 | Recipient: Aghorn Operating Inc. | Status: Closed – Acceptable Action | For all waterflood stations where the potential exists to expose non-employees to H2S concentrations at or above 10 ppm, develop and implement a formal, written, site-specific security program to prevent unknown and unplanned entrance of those not employed by Aghorn, starting with a requirement for employees to lock access gates upon entering and departing the facility.
  8. 2020-01-I-TX-R8 | Recipient: Occupational Safety and Health Administration (OSHA) | Status: Closed – Acceptable Action | Issue a safety information product (such as a safety bulletin or safety alert) that addresses the requirements for protecting workers from hazardous air contaminants and from hazardous energy.
  9. 2020-01-I-TX-R9 | Recipient: The Railroad Commission of Texas | Status: Closed – Acceptable Action | Develop and send a Notice to Operators to all oil and gas operators that fall under the jurisdiction of the Railroad Commission of Texas that describes the safety issues described in this report, including: 1. Nonuse of Personal H2S Detector 2. Nonperformance of Lockout / Tagout 3. Confinement of H2S Inside Pump House 4. Lack of Safety Management Program 5. Nonfunctioning H2S Detection and Alarm System 6. Deficient Site Security

Key Engineering Lessons

  • Personal H2S detection devices were identified as a required safeguard for workers and visitors in areas with the potential for H2S exposure.
  • A formal Lockout / Tagout program is necessary to prevent work on energized equipment.
  • Pump house ventilation and mitigation systems must be evaluated so that accidental releases do not lead to confinement of toxic gas inside the building.
  • H2S detection and alarm systems should be properly maintained, configured, and designed with multiple layers of alerts, including audible and visual means.
  • Site security controls, including locked access gates and formal security procedures, are needed to prevent unplanned entry by non-employees.

Source Notes

  • Priority 1 final report information was used to resolve conflicts and establish the authoritative incident narrative.
  • Recommendation status change summaries were used to update recommendation statuses and confirm post-incident corrective actions.
  • Supporting documents were used only where they added detail consistent with the final report and did not override higher-priority findings.

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