TPC Group Butadiene Explosions and Fires | SafeGuard PSM Case Study

📋 Incident Summary

Shortly before 1 a.m. on November 27, 2019, a section of piping in TPC Group's butadiene processing unit at Port Neches, Texas, ruptured due to blockage caused by popcorn polymer accumulation. The rupture released a large quantity of highly flammable butadiene that ignited, producing a massive explosion felt up to 30 miles away. Fires fueled by continuing butadiene release burned for more than a month. Two TPC workers and one security contractor sustained injuries.

The explosion caused an estimated $450 million in on-site property damage and $153 million in off-site damage to nearby homes and businesses. Thousands of residents near the facility were ordered to evacuate following multiple explosions and fires at the site.

The CSB found that TPC Group failed to adequately manage the known hazard of popcorn polymer formation in high-purity butadiene systems and did not implement sufficient internal policies to direct operators to shut down and clean butadiene units after detecting elevated popcorn polymer levels — a well-documented industry hazard.

🔎 Key Findings

Finding 01

Popcorn Polymer Accumulation Blocked Butadiene Piping — Causing Catastrophic Rupture

Popcorn polymer, a hazardous autocatalytic solid that forms spontaneously in butadiene service under certain conditions, accumulated in a section of TPC's butadiene piping. The blockage built pressure until the piping catastrophically ruptured, releasing butadiene that immediately ignited.

Finding 02

TPC Failed to Implement Adequate Popcorn Polymer Management Procedures

TPC Group did not have adequate written procedures directing operators to shut down and clean butadiene processing units when elevated levels of popcorn polymer were detected. The absence of clear action thresholds allowed the hazard to escalate without corrective action.

Finding 03

Industry Knew Popcorn Polymer Was a Serious Hazard — TPC Did Not Act on That Knowledge

The hazard of popcorn polymer in high-purity butadiene systems is documented in industry literature and guidance. The CSB found that TPC was aware of the hazard but had not implemented the policies and safeguards necessary to prevent its buildup from reaching catastrophic levels.

Finding 04

Explosion Felt 30 Miles Away — $600M+ Total Property Damage

The butadiene explosion was severe enough to be felt 30 miles from the facility. On-site and off-site property damage combined exceeded $600 million, with extensive damage to homes and businesses in the surrounding community. The subsequent fires burned continuously for more than a month.

Finding 05

Dead Legs in Butadiene Piping Created Locations for Polymer Accumulation

The CSB identified that piping dead legs — sections of piping that are out of service or have no flow — in butadiene service provided locations where popcorn polymer could accumulate without detection or purging, creating a chronic hazard that went unrecognized until rupture.

🔍 Root Causes

Popcorn Polymer Hazard Not Adequately Managed — No Shutdown Threshold Procedures

TPC Group recognized that popcorn polymer was a hazard in its butadiene systems but had not implemented adequate procedures specifying the conditions — including elevated polymer detection — that required unit shutdown and cleaning. The hazard was known but not operationally controlled.

Dead Legs in Butadiene Service Allowed Polymer Accumulation Without Detection

Piping dead legs in TPC's butadiene unit provided stagnant zones where popcorn polymer could accumulate without process flow to detect blockage formation. The dead legs had not been identified, eliminated, or managed under a program specifically addressing their risk in high-purity butadiene service.

CSB Recommendation from Prior Industry Incidents Had Not Been Implemented

The CSB noted that the industry had prior knowledge of popcorn polymer hazards from previous incidents and that CSB recommendations addressing this hazard had not been adopted by TPC — representing a failure to learn from past industry events.

☑ CSB Recommendations

→ TPC Group / Industry

Develop and implement written procedures specifying conditions — including detection of popcorn polymer at defined levels — that require shutdown and cleaning of high-purity butadiene processing units; ensure procedures include shutdown triggers and cleaning protocols.

→ TPC Group / Industry

Identify and eliminate or manage all dead legs in high-purity butadiene service piping; include dead leg identification and management in PHA reviews and MI programs for butadiene processing units.

→ American Chemistry Council / Industry Associations

Develop and publish comprehensive industry guidance for management of popcorn polymer hazards in butadiene service, including detection methods, monitoring intervals, shutdown triggers, and cleaning procedures; ensure guidance is incorporated into PHA review criteria.

→ OSHA

Evaluate existing PSM enforcement guidance related to reactive hazards including popcorn polymer formation in butadiene service; issue guidance to industry on required hazard management elements for high-purity butadiene processing.

💡 Lessons Learned

Popcorn polymer is a well-documented, autocatalytic hazard specific to high-purity butadiene systems. It forms spontaneously, grows rapidly, and can block piping to the point of catastrophic rupture. Facilities processing high-purity butadiene must have specific written procedures — not general maintenance policies — that define detection methods, monitoring intervals, and mandatory shutdown thresholds when polymer is detected.

Dead legs in hazardous service piping are not merely a maintenance inconvenience — they are process hazard locations. In butadiene service, a dead leg is a location where polymer can accumulate without any flow-based indicator of blockage. Dead legs in hazardous service must be identified in PHA reviews and either eliminated or incorporated into an active monitoring program.

The fact that both the CSB and the industry had documented popcorn polymer as a serious hazard before the TPC Port Neches explosion — and that TPC had not implemented adequate controls — illustrates a critical failure mode: knowing about a hazard without converting that knowledge into operational controls. Process safety programs must systematically track how industry hazard lessons are applied to current operations, not just acknowledged.

The $600 million combined property damage from the TPC explosion demonstrates that community consequence is a real financial and operational risk even when fatalities do not occur. Nearby residents sustained significant damage to their homes and properties. Facilities with highly flammable materials in large quantities must model off-site consequence scenarios and ensure community emergency plans address large-scale evacuation.

A fire that burns for more than a month is not a fire that can be fought with conventional suppression — it is a consequence-management problem requiring coordination with local agencies, environmental authorities, and the surrounding community over an extended period. Emergency plans for facilities with large inventories of flammable materials must address extended-duration incident scenarios.

PSI: Process Safety InformationPHA: Process Hazard AnalysisMI: Mechanical IntegritySOP: Operating ProceduresEP: Emergency Planning

🔨 Safety Meeting Toolbox Talk

►If your facility processes high-purity butadiene, do you have written procedures specifying the conditions — including polymer detection thresholds — that require unit shutdown and cleaning? When were those procedures last reviewed?

►Has your facility identified and inventoried all dead legs in hazardous service piping, including butadiene, propylene, ethylene, and other highly flammable systems? Are dead legs addressed in your PHA and MI programs?

►How does your facility track industry incident lessons — including CSB reports — and ensure that applicable hazard findings are evaluated against your current operations and incorporated into your PSM program?

►Does your emergency preparedness plan address extended-duration fires involving large inventories of flammable materials? Have you coordinated with local agencies on resource and notification requirements for a multi-day incident?

Immediate Action Items

✓If your facility operates high-purity butadiene or other reactive monomer systems, audit existing procedures for popcorn polymer management — confirm that shutdown triggers, monitoring requirements, and cleaning protocols are documented and operationally enforced.

✓Conduct a dead leg identification survey for all hazardous service piping systems; document findings and develop a plan to eliminate, isolate, or actively monitor all identified dead legs as part of your MI program.

✓Establish or verify that a formal process exists for tracking CSB and industry incident reports, evaluating their applicability to your facility, and documenting how applicable findings are addressed in your PSM program.

✓Review your emergency preparedness plan for extended-duration scenarios involving large flammable inventories; confirm coordination protocols with local emergency management, environmental response agencies, and community notification systems.

🔗 PSM Failures Behind This Incident

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

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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Mechanical Integrity (MI)

Equipment must be designed, inspected, and maintained to operate safely in its intended service. Mechanical integrity failures — degraded equipment, missed inspections, deferred repairs — contributed to loss of containment here.

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Operating Procedures (SOPs)

Operators cannot reliably hold safe operating limits without clear, current, enforced procedures. Deviation from acceptable operating conditions — a root cause here — is a direct consequence of SOP failure.

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Employee Participation

OSHA PSM requires workers to be meaningfully involved in hazard analyses and procedure development — not just trained on the finished product. Active participation catches gaps that management alone misses.

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