Skip to content

AirGas Facility Fatal Explosion

Overview

On August 28, 2016, a nitrous oxide trailer truck exploded at the Airgas manufacturing facility in Cantonment, Florida. The CSB determined the most probable cause was that, during initial loading of a trailer truck, a pump heated nitrous oxide above its safe operating limits. This likely initiated a nitrous oxide decomposition reaction that propagated into the trailer truck and caused the explosion. The incident killed the only Airgas employee present, heavily damaged the facility, and halted nitrous oxide manufacturing at Cantonment indefinitely. The CSB found that Airgas lacked an effective process safety management system to identify, evaluate, and control process safety-related hazards.

Incident Snapshot

Field Value
Facility / Company Airgas, Inc. (Air Liquide)
Location Pensacola, FL; incident occurred at the Airgas manufacturing facility in Cantonment, Florida
Incident Date 08/28/2016
Investigation Status The CSB's investigation report was released at a news conference in Pensacola, FL, on 4.20.2017. The CSB's final report was released at a news conference in Pensacola, FL on 4/20/2017.
Accident Type Chemical Manufacturing - Fire and Explosion Investigation
Final Report Release Date 04/20/2017

What Happened

  • On August 28, 2016, a nitrous oxide trailer truck exploded at the Airgas manufacturing facility in Cantonment, Florida.
  • During the initial loading of a trailer truck, a pump heated nitrous oxide above its safe operating limits.
  • This likely started a nitrous oxide decomposition reaction that propagated from the pump into the trailer truck, causing the explosion.
  • The explosion fatally injured the only Airgas employee and heavily damaged the facility.
  • The explosion rendered the Airgas facility inoperable and halted nitrous oxide manufacturing at Cantonment indefinitely.
  • Following the incident, Airgas began a comprehensive initiative to review the safety programs for its nitrous oxide production facilities, trucking fleet, and cylinder-filling operations.

Facility and Process Context

  • Airgas manufacturing facility in Cantonment, Florida.
  • Nitrous oxide manufacturing at Cantonment.
  • Nitrous oxide production facilities, trucking fleet, and cylinder-filling operations.
  • From storage, Airgas pumps the cold liquid nitrous oxide into insulated trailer trucks or shipping containers.
  • Airgas used the two-hose method for truck loading at Cantonment.
  • The truck loading process required manual operation by on-site personnel, with no automatic controls other than the safety interlock associated with the pump.

Consequences

  • Fatalities: 1
  • Injuries: 0
  • Environmental release: roughly 250,000 pounds of nitrous oxide was released to the atmosphere
  • Facility damage: heavily damaged the facility; large metal fragments of equipment were scattered for hundreds of feet; damage rendered the Airgas facility inoperable; total loss of the Airgas Cantonment facility
  • Operational impact: halting nitrous oxide manufacturing at Cantonment indefinitely

Key Findings

Immediate Causes

  • During the initial loading of a trailer truck, a pump heated nitrous oxide above its safe operating limits.
  • Exceeding these critical safety limits appears to have started a nitrous oxide decomposition reaction that propagated from the pump into the trailer truck, causing the explosion.
  • Based on conditions and design of the pump system, the pump likely lost prime or ran dry during startup, which generated heat and increased the temperature of pump components.

Contributing Factors

  • Airgas did not evaluate inherently safer design options that could have eliminated the need for the pump.
  • Airgas did not effectively apply the hierarchy of controls to the safeguards that the company used to prevent a possible nitrous oxide explosion.
  • Airgas installed equipment that increased the likelihood of an explosion without performing a management of change safety review.
  • Airgas did not apply an essential industry safety instrumentation standard, or key elements of a voluntary safe storage and handling standard, both of which are intended to prevent nitrous oxide explosions.
  • The automatic shutdown safety control Airgas relied on required the Airgas worker to be physically present and located immediately adjacent to the trailer truck in order to bypass the shutdown at a time when an explosion was most likely to occur.
  • The Airgas explosion prevention device, a flame arrestor, was never tested or inspected to ensure it could protect workers from an explosion.
  • Airgas did not provide its Cantonment facility with an appropriate level of technical staffing support.
  • Airgas did not have a testing procedure for the run-dry safety interlock, and the method employees use to confirm that the safety system is functional creates unnecessary danger to workers because it could initiate an explosion.
  • Airgas did not account for the pressure drop across y-strainers stuffed with steel wool that the company used as a flame arrestor.
  • Airgas did not perform an engineering analysis or install instrumentation to ensure that using a y-strainer filled with steel wool on the pump suction piping would not result in dry running conditions.
  • Airgas never established or evaluated a minimum required nitrous oxide storage tank level.
  • Airgas did not perform piping stress analysis to ensure that initial cool down does not produce excessive stress on the pump.
  • Airgas did not have a program to ensure effective electrical bonding or grounding when loading or moving nitrous oxide to trailer trucks or shipping containers.
  • Airgas did not identify the trailer truck loading operation as an area where an explosive nitrous oxide decomposition reaction could occur.
  • Airgas provided no effective safeguards and simply instructed the operators to stop the pump if there was a marked change in sound level.
  • Airgas required the operator to be physically present and listen to the pump in order to prevent a nitrous oxide explosion.
  • ACD product literature provided few details about pump hazards related to nitrous oxide service.
  • Their product literature provided few, if any, details about pump hazards related to nitrous oxide service.

Organizational and Systemic Factors

  • Airgas did not have an effective safety management system that identifies, evaluates, and controls process safety-related hazards like those that led to the explosion.
  • The CSB investigation found that Airgas lacked a safety management system to identify, evaluate, and control nitrous oxide process safety hazards, which led to the explosion.
  • The contributing causes of the explosion all stemmed from the company’s lack of an effective overall process safety management system.
  • Airgas management systems did not adequately focus on process safety.
  • Airgas management did not observe established industry safety standards and good practices.
  • Airgas management did not embrace its own lessons learned from past incidents.
  • Airgas did not complete or develop a plan to perform a process hazard analysis on the nitrous oxide manufacturing operations at the Cantonment, Florida facility.
  • Airgas did not have any technical personnel located at the Cantonment facility.
  • Airgas did not have a preventive maintenance program for nitrous oxide pumps.
  • Airgas relied on equipment manufacturers to perform pump system engineering.
  • Airgas did not perform a hazard review or management of change when the company designed, installed, and began using the Cryostar centrifugal pump.
  • Airgas did not have documentation explaining the warning not to use steel wool, whether in the manual or any other corporate documents provided to the CSB.
  • Airgas lacked an engineering standard for strainers used as a flame arrestor.
  • Airgas did not conduct any testing to confirm that a y-strainer filled with steel wool can actually halt a nitrous oxide decomposition reaction.
  • Airgas audit did not assess the accuracy of the critical equipment list.
  • The annual safety audit conducted by a corporate Airgas safety official lacked a process safety focus.
  • The Airgas audit program did not challenge the status quo with respect to existing, and in some cases long-standing, process safety issues.
  • Airgas management could have prevented or remedied such problems by supplementing its workforce with additional technical staff and by expanding the responsibilities of technically oriented corporate safety staff.

Failed Safeguards or Barrier Breakdowns

  • effective safety management system that identifies, evaluates, and controls process safety-related hazards
  • process safety management components
  • management of change
  • project risk identification process
  • automatic shutdown safety control
  • explosion prevention device
  • run-dry safety interlock
  • flame arrestor
  • y-strainers filled with steel wool
  • low-flow interlock
  • pressure relief device on the pump outlet piping
  • man down system
  • storage tank low-level alarm
  • electrical bonding or grounding program
  • safety interlocks
  • automatic pump shutoff
  • inspection program for nitrous oxide flame arrestors
  • preventive maintenance program for nitrous oxide pumps

Recommendations

  1. 2016-04-I-FL-R1 | Recipient: Airgas, Inc. | Status: Closed - Exceeds Recommended Action | Complete Post-Incident Actions and Process Safety Initiatives for Nitrous Oxide Operations
  2. 2016-04-I-FL-R2 | Recipient: Compressed Gas Association | Status: Closed – Exceeds Recommended Action | Develop and implement a safety management system standard for nitrous oxide manufacturing, to manage known process safety hazards, including nitrous oxide decomposition, which includes appropriate elements based on chemical industry good practice guidance, such as CCPS Guidelines for Risk Based Process Safety, Essential Practices for Managing Chemical Reactivity Hazards, and Guidelines for Implementing Process Safety Management.
  3. 2016-04-I-FL-R3 | Recipient: Compressed Gas Association | Status: Closed – Acceptable Alternative Action | Ensure Effective Flame Arrestor Design. Modify Compressed Gas Association (CGA) standard CGA G-8.3, Safe Practices for Storage and Handling of Nitrous Oxide to require testing of safety devices, such as strainers used as flame arrestors, for applications where a safety device is used to quench a nitrous oxide decomposition reaction. To ensure that these safety devices meet the intended purpose, the user should test the safety device by simulating conditions of use. In addition, require users to document the required performance standard or test protocol followed.
  4. 2016-04-I-FL-R4 | Recipient: Compressed Gas Association | Status: Closed – Acceptable Action | Modify Compressed Gas Association (CGA) standard CGA G-8.3, Safe Practices for Storage and Handling of Nitrous Oxide to reference and require applying International Society of Automation (ISA) standard ISA-84, Functional Safety: Safety Instrumented Systems for the Process Industry Sector to safety interlocks such as the nitrous oxide pump “run-dry” shutdown.
  5. 2016-04-I-FL-R5 | Recipient: ACD LLC | Status: Closed – Acceptable Action | Provide effective warning about nitrous oxide decomposition hazards. Modify nitrous oxide pump product literature to include warnings about nitrous oxide decomposition hazards, illustrated by examples from historical incidents, and refer users to this CSB investigation report for additional information.
  6. 2016-04-I-FL-R6 | Recipient: Cryostar USA, LLC | Status: Closed – Acceptable Action | Provide effective warning about nitrous oxide decomposition hazards. Modify nitrous oxide pump product literature to include warnings about nitrous oxide decomposition hazards, illustrated by examples from historical incidents, and refer users to this CSB investigation report for additional information.

Key Engineering Lessons

  • Pump dry-running or loss of prime can generate heat sufficient to initiate nitrous oxide decomposition; run-dry protection must be treated as critical safety protection.
  • Flame arrestors or strainers used as flame arrestors should be tested for the specific nitrous oxide decomposition-quenching application and under simulated conditions of use.
  • Changes to nitrous oxide transfer equipment, including replacement pumps, require management of change review and hazard analysis before implementation.
  • Process hazard analysis should explicitly address nitrous oxide decomposition hazards during trailer loading and identify effective safeguards.
  • Safety interlocks for nitrous oxide service should be evaluated using ISA-84 where applicable.
  • Product literature for nitrous oxide pumps should clearly warn users about decomposition hazards and the consequences of dry running.

Source Notes

  • Priority 1 final report findings were used to resolve conflicts and establish the authoritative incident description.
  • The incident location in the source documents is Cantonment, Florida; the crawler metadata listed Pensacola, FL as the location for the news conference/release.
  • The final report and related documents consistently identify the event as a nitrous oxide trailer truck explosion at the Airgas manufacturing facility in Cantonment, Florida.
  • Recommendation status changes from later documents were included where explicitly stated, but the incident findings were not altered by lower-priority sources.
  • All facts are taken directly from the provided extracts; no external information was added.
  • https://www.csb.gov/airgas-facility-fatal-explosion-/

Similar Incidents

Incidents sharing the same equipment, root causes, or hazard types.

Same Equipment

Same Root Cause

Same Hazard

← View in Knowledge Graph