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T2 Laboratories Inc. Reactive Chemical Explosion

Overview

At 1:33 pm on December 19, 2007, a powerful explosion and subsequent chemical fire occurred at T2 Laboratories, Inc. in Jacksonville, Florida during production of methylcyclopentadienyl manganese tricarbonyl (MCMT). Four employees were killed and 32 people were injured, including employees and members of the public. The CSB found that a runaway exothermic reaction occurred during the first (metalation) step of the MCMT process.

Incident Snapshot

Field Value
Facility / Company T2 Laboratories, Inc.
Location Jacksonville, FL
Incident Date 12/19/2007
Investigation Status The CSB final report was approved by the Board at a public meeting in Jacksonville, Florida, on 9/15/2009.
Accident Type Reactive Incident
Final Report Release Date 09/15/2009

What Happened

  • On the evening of December 18, 2007, a night shift process operator cleaned and dried the reactor in preparation for a new MCMT batch.
  • At about 7:30 am on December 19, the day shift process operator began manufacturing Batch 175 from the control room adjacent to the process line.
  • An outside operator hand-loaded the reactor with blocks of sodium metal, then sealed the reactor.
  • At about 11:00 am, the process operator began heating the batch to melt the sodium and initiate the chemical reaction, while monitoring the temperature and pressure on the process control screen.
  • Once the sodium melted, at 210°F (98.9°C), the process operator likely started the mixer (agitator).
  • At a reaction temperature of about 300°F (148.9°C), the process operator likely turned off the heating system as specified in the procedure.
  • At a temperature of about 360°F (182.2°C), the process operator likely started cooling, using the process control system, as specified in the procedure.
  • At 1:23 pm, the process operator had an outside operator call the owners to report a cooling problem and request they return to the site.
  • Upon their return, one of the owners went to the control room to assist.
  • By 1:33 pm, the reactor’s relief system could no longer control the rapidly increasing temperature and pressure of the runaway reaction.
  • The reactor violently ruptured, its contents exploding.

Facility and Process Context

  • T2 Laboratories, Inc. was a small privately-owned chemical manufacturer located in Jacksonville, Florida.
  • T2 began operations in 1996 and later leased a 5-acre site in north Jacksonville industrial area.
  • In January 2004, T2 began producing MCMT in a batch reactor.
  • By December 2007, MCMT production was the primary business operation.
  • On the day of the incident, T2 employed 12 people and was producing its 175th MCMT batch (Batch 175).
  • T2 manufactured MCMT in a single reactor in batches using a three-step chemical process.
  • The reactor was about ten feet high and seven feet wide and was held vertically in a tall steel support structure.
  • The control room was a square 12-foot concrete building located just 50 feet from the reactor.
  • The tank farm contained thousands of gallons of flammable solvents.
  • The Jacksonville Fire and Rescue Department had inspected T2 prior to the incident and had conducted hazardous materials response drills for sodium metal based on the chemicals T2 reported storing.

Consequences

  • Four T2 employees died.
  • 32 were injured, including four employees and 28 members of the public who were working in surrounding businesses.
  • Soil and groundwater on the site remain contaminated with manganese and benzene.
  • The explosion destroyed T2 Laboratories, Inc.; debris from the reactor was found up to one mile away; the explosion damaged buildings within one quarter mile of the facility; the City of Jacksonville subsequently condemned buildings used by four of the businesses surrounding T2; the explosion destroyed a trucking company office trailer located 250 feet from the reactor; two warehouses located about 400 to 500 feet from the reactor both sustained heavy damage.
  • T2 ceased production operations.

Key Findings

Immediate Causes

  • A runaway exothermic reaction occurred during the first (metalation) step of the MCMT process.
  • The blast occurred due to a runaway chemical reaction that generated high temperature and pressure in the reactor.
  • The reactor violently ruptured when the relief system could no longer control the rapidly increasing temperature and pressure.
  • Insufficient cooling was the only credible cause identified for the incident.

Contributing Factors

  • The cooling system employed by T2 was susceptible to single-point failures due to a lack of design redundancy.
  • The MCMT reactor relief system was incapable of relieving the pressure from a runaway reaction.
  • The operating procedures used at the time of the incident included no emergency instructions for loss of cooling.
  • A secondary (backup) source of water stored on site was not immediately available to the process operator in an emergency.
  • T2 sized the reactor relief devices based on anticipated normal operations, without considering potential emergency conditions.
  • There was no evidence that T2 evaluated a runaway reaction as a possible overpressure source.
  • The emergency vent system was designed for normal operation and not designed to consider a runaway reaction.
  • The set pressure of the emergency vents was set too high.
  • The cooling system likely malfunctioned, perhaps due to a blockage in the water supply piping or a valve failure.
  • T2's development work was incapable of determining exothermic activity and this uncontrollable outcome went undetected.
  • Temperature control issues and near miss exothermic reactions occurred in three of the first ten production batches but T2's owners did not systematically investigate these anomalies to determine their cause.
  • Throughout the production history poor yields and batch flow variations occasionally occurred due to temperatures rising too high in the first step.
  • The cooling system lacked redundancy.
  • Because no emergency system was immediately available, operators would need to manually attach hoses to access an additional water supply in the event of a failure.
  • The need to cool the first step was not identified until the first full-scale production batch.
  • The T2 owners were likely unaware of the second exothermic reaction that occurred in the batch recipe at high temperatures.

Organizational and Systemic Factors

  • T2 did not recognize the runaway reaction hazard associated with the MCMT it was producing.
  • Neither of the T2 owners had prior reactive chemistry experience.
  • Although T2's owners had chemical industry experience, neither had previously worked with reactive chemistry and did not have experience developing and designing a reactive exothermic process like the MCMT chemistry.
  • Chemists and chemical engineers involved in developing and operating the T2 MCMT process were unaware of the need to perform runaway reaction testing, address emergency relief, and identify and evaluate the causes of process upsets.
  • T2 did not repeat batch recipes to isolate the problem, instead changing recipes in each of the first 10 batches.
  • When the MCMT process yielded unexpected results in early batches, T2 did not halt production, investigate causes, and redesign the process.
  • As demand grew, T2 increased batch size and frequency with no additional documented hazard analysis.
  • T2's owners conducted laboratory testing of the MCMT process chemistry, but this testing did not look for the potential exothermic reaction in the first step of the process.
  • T2 was never able to fully control these batch variations and continued to use the same recipe that it had established in the early batches.
  • There is no documentation that T2 further addressed potential OSHA requirements.
  • The patents do not describe the safety measures that must be in place for full scale production.
  • The patents also do not address the heat production or exotherm that occurs in the first step of the process.
  • Reactivity hazard awareness is not currently a fundamental component of chemical engineering curricula.
  • There is no requirement for accredited baccalaureate chemical engineering programs to include process safety or reactive hazard awareness in their curricula.
  • In 2006 the Mary K. O'Connor Process Safety Center conducted a survey of undergraduate chemical engineering programs and found that process safety was a part of the required curriculum in only 11 percent of the programs.
  • Within these programs, inclusion of reactive hazard recognition and management was even more limited.
  • The fire department was aware of the solvents and sodium on site and did inspections, but they were never informed of the MCMT production that was going on at the site.
  • T2 submitted a report under an EPA regulation that reported the various solvents and the raw materials and the sodium that they had on site, but did not include the actual methylcyclopentadiene and diethylene glycol.
  • There were no commonly available immediate measurement techniques that could be used in the field to detect the MCMT.

Failed Safeguards or Barrier Breakdowns

  • The cooling system employed by T2 was susceptible to single-point failures due to a lack of design redundancy.
  • The MCMT reactor relief system was incapable of relieving the pressure from a runaway reaction.
  • The operating procedures used at the time of the incident included no emergency instructions for loss of cooling.
  • A secondary (backup) source of water stored on site was not immediately available to the process operator in an emergency.
  • CSB found no evidence that T2 ever performed the HAZOP.
  • T2 could not provide any documents related to the sizing and set point of the rupture disk.
  • T2 did not include MCMT in annual Tier II reports.
  • The reactor cooling system was susceptible to single point failure.
  • The reactor relief system was incapable of releasing the pressure from a runaway reaction.
  • The emergency vent system was designed for normal operation and not designed to consider a runaway reaction.
  • The set pressure of the emergency vents was set too high.
  • T2's development work was incapable of determining exothermic activity.
  • T2's owners did not systematically investigate anomalies to determine their cause.
  • No emergency system was immediately available.
  • T2 Laboratories never did any testing to determine whether they were covered and did not do what OSHA did to make a determination of coverage.
  • The actual methylcyclopentadiene and diethylene glycol were not included in the report that was sent to the LAPC and the fire department.

Recommendations

  1. 2008-03-I-FL-R1 — Recipient: Accreditation Board for Engineering and Technology, Inc. — Status: Not specified — Work with the Accreditation Board for Engineering and Technology, Inc. to add reactive hazard awareness to baccalaureate chemical engineering curricula requirements.
  2. 2008-03-I-FL-R2 — Recipient: American Institute of Chemical Engineers — Status: Not specified — Inform all student members about the Process Safety Certificate Program and encourage program participation.
  3. 2008-03-I-FL-R3 — Recipient: Accreditation Board for Engineering and Technology, Inc. — Status: Not specified — Work with the American Institute of Chemical Engineers to add reactive hazard awareness to baccalaureate chemical engineering curricula requirements.

Key Engineering Lessons

  • Runaway reaction hazards must be recognized during process development for reactive chemistry systems.
  • Cooling systems for exothermic batch reactions should not rely on single-point failure-prone designs.
  • Relief systems must be evaluated for runaway reaction overpressure, not only normal operating conditions.
  • Emergency procedures should include loss-of-cooling response and immediate access to backup cooling water.
  • Laboratory and pilot testing should look for unintended exothermic activity in all reaction steps before full-scale production.
  • Unexpected batch anomalies and near-miss exothermic behavior should be systematically investigated before production is expanded.

Source Notes

  • Priority 1 final report used as the authoritative source for conflict resolution.
  • Priority 4 transcript was used only to supplement context where it did not conflict with the final report.
  • Terminology preserved from the source documents where possible, including MCMT, runaway reaction, and HAZOP.
  • Some duplicate or variant equipment and chemical names from the transcript were consolidated with the final report's terminology.

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