Explosion And Fire
CF Industries Nitrogen Plant Explosion
CF Industries Holdings, Inc.
📍 Donaldsonville, LA
Incident: June 13, 2016 • CSB Report: 2019
1
Fatalities
2
Injuries / Affected
High-Pressure Nitrogen (Nitrogen Plant Explosion During Maintenance — Rapid Deco
Chemical Involved
3
CSB Recommendations
📋 Incident Summary

On June 13, 2016, one worker was killed and two others were injured when an explosion occurred at a nitrogen plant at the CF Industries fertilizer manufacturing complex in Donaldsonville, Louisiana. CF Industries operates one of the largest fertilizer manufacturing facilities in the world at the Donaldsonville site.

The explosion occurred during maintenance operations on the nitrogen plant. Workers were performing a maintenance procedure that required depressurizing and isolating a section of high-pressure nitrogen equipment. The procedure was not correctly executed, and the equipment was not adequately isolated before maintenance work began. When the equipment was opened, the sudden release of high-pressure nitrogen caused a rapid decompression event that resulted in the explosion.

The CSB investigation found that the maintenance procedure for the nitrogen plant work did not provide adequate guidance for the isolation and depressurization steps required before opening high-pressure equipment. The procedure as written allowed for ambiguity in the critical isolation steps, and the workers performing the work did not have a clear, step-by-step procedure that ensured the equipment was fully isolated and depressurized before opening.

🔎 Key Findings
Finding 01
Maintenance Procedure Did Not Adequately Define Isolation and Depressurization Steps
The maintenance procedure for the nitrogen plant work did not provide clear, unambiguous step-by-step guidance for isolating and depressurizing the equipment before opening. Ambiguity in critical isolation steps was a primary contributor to the fatal incident.
Finding 02
Equipment Opened While Still Under High Pressure
The equipment was opened by maintenance workers before it had been fully isolated and depressurized. The resulting rapid release of high-pressure nitrogen caused the explosion that killed one worker.
Finding 03
High-Pressure Nitrogen System Maintenance Requires Rigorous Isolation Procedures
High-pressure nitrogen equipment maintenance presents specific hazards from the energy stored in compressed gas. Isolation procedures for high-pressure nitrogen systems must be explicit, step-by-step, and verified before any equipment opening is performed.
Finding 04
One Worker Killed — Two Injured
One maintenance worker was killed and two others were injured in the explosion. The incident occurred during a maintenance activity that should have been a routine operation but was not adequately protected by the procedure and isolation verification in place.
Finding 05
LOTO and Isolation Verification Not Adequate for High-Pressure Nitrogen Service
The lockout/tagout and isolation verification program for the nitrogen plant maintenance activity was not adequate to ensure that the equipment was fully depressurized before opening. Verification of isolation for high-pressure gas systems requires specific steps beyond standard LOTO.
🔍 Root Causes
1
Ambiguous Isolation Procedure for High-Pressure Nitrogen Equipment
The maintenance procedure did not provide clear, unambiguous guidance for isolating and verifying depressurization of the high-pressure nitrogen equipment before opening. Ambiguity in the critical isolation steps allowed workers to proceed without confirming that the system was fully depressurized.
2
Isolation Verification Not Confirmed Before Equipment Opening
Workers opened the high-pressure nitrogen equipment without confirming that isolation and depressurization were complete. The absence of a mandatory, verified depressurization confirmation step before opening was the immediate cause of the explosion.
3
High-Pressure Gas System Maintenance Not Adequately Controlled by LOTO Program
The facility LOTO program was not specifically adapted for high-pressure nitrogen system maintenance. High-pressure gas systems require specific isolation and pressure verification steps that go beyond standard electrical LOTO procedures.
☑ CSB Recommendations
→ CF Industries / Fertilizer Manufacturers
Revise maintenance procedures for all high-pressure nitrogen and compressed gas equipment to include explicit, step-by-step isolation and depressurization instructions with mandatory verification steps before equipment opening; implement pressure verification requirements before maintenance activities on high-pressure systems.
→ Fertilizer Manufacturing Industry
Develop industry guidance on LOTO and isolation verification for high-pressure gas systems; address the specific energy hazards of compressed gas systems that differ from electrical LOTO hazards.
→ OSHA
Issue guidance clarifying LOTO requirements for high-pressure gas and pneumatic energy systems; address the verification requirements for depressurization before maintenance on high-pressure gas equipment.
💡 Lessons Learned
Compressed gas energy is one of the most underappreciated stored energy forms in process facilities. Workers who are well-trained on electrical LOTO may not have equivalent training on the energy stored in high-pressure compressed gas systems and the specific steps required to verify that this energy has been safely released before maintenance. The OSHA LOTO standard was developed primarily with electrical energy in mind; pneumatic and compressed gas energy require additional, system-specific verification procedures that must be written explicitly into maintenance procedures.
Procedure ambiguity kills. A maintenance procedure that leaves critical isolation steps open to interpretation — where a worker must decide whether a step has been completed satisfactorily without an explicit verification requirement — is a procedure that will eventually fail under operational pressure. Maintenance procedures for energy-isolation steps on high-pressure systems must specify the isolation method, the verification method, the acceptable test result, and the hold point before proceeding. Anything less is not a procedure — it is a suggestion.
The fertilizer industry operates some of the highest-pressure nitrogen, ammonia, and compressed gas systems in the chemical manufacturing sector. These systems contain enormous amounts of stored energy. Maintenance procedures for high-pressure systems at fertilizer plants must reflect the specific energy content of the systems being worked on and must provide verification steps commensurate with the consequences of an inadequate isolation.
SOP: Operating ProceduresPSI: Process Safety InformationPHA: Process Hazard AnalysisTRN: TrainingINC: Incident Investigation
🔨 Safety Meeting Toolbox Talk
►Do maintenance procedures for all high-pressure compressed gas and pneumatic energy systems at your facility include explicit, step-by-step isolation and depressurization instructions with mandatory verification steps (e.g., pressure gauge readings, bleed valve confirmation) before equipment opening?
►Has your LOTO program been specifically adapted for high-pressure gas and pneumatic energy sources? Do workers understand the verification requirements that differ from standard electrical LOTO?
►When was the last procedure review for high-pressure nitrogen, compressed air, or steam system maintenance at your facility? Were the critical isolation steps evaluated for clarity and adequacy by a subject matter expert familiar with the specific energy hazards?
Immediate Action Items
✓Review all maintenance procedures for high-pressure compressed gas, nitrogen, steam, and pneumatic systems; verify that isolation and depressurization steps are explicit, step-by-step, and include mandatory pressure verification before equipment opening.
✓Update LOTO program to specifically address compressed gas and high-pressure pneumatic energy sources; train maintenance workers on the specific hazards and isolation verification requirements for these energy sources.
✓Implement mandatory hold points in high-pressure maintenance procedures that require supervisor or independent verification of isolation and depressurization before work can proceed.
✓Conduct a procedure quality review for all high-pressure system maintenance procedures; eliminate ambiguous language in critical isolation and depressurization steps.
🔗 PSM Failures Behind This Incident

This incident traced to breakdowns across 5 PSM elements (SOP · PSI · PHA · TRN · INC). Each represents a documented gap that process safety documentation and consulting can close before a similar event occurs at your facility.

Operating Procedures (SOPs)
Operators cannot reliably hold safe operating limits without clear, current, enforced procedures. Deviation from acceptable operating conditions is a direct consequence of SOP failure.
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Process Safety Information (PSI)
Accurate, complete Process Safety Information is the foundation every other PSM element depends on. When PSI is missing or wrong — chemistry data, equipment specs, P&IDs — the entire hazard analysis is built on a flawed base.
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Process Hazard Analysis (PHA)
A structured PHA or HAZOP study exists to identify exactly these scenarios before they occur. When PHA is absent, superficial, or overdue for revalidation, hazards operate unseen until they kill someone.
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Training & Operator Competency
Workers must understand process hazards — not just the steps on the page. Training records, refresher frequency, and verified competency are all OSHA PSM requirements.
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Incident Investigation
Near-misses and prior incidents almost always signal the exact failure mode that eventually becomes fatal. When investigation is absent or superficial, those warnings go unheeded until consequences arrive.
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