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Morton International Inc. Runaway Chemical Reaction

Overview

On April 8, 1998, an explosion and fire occurred during production of Automate Yellow 96 Dye at the Morton International, Inc. plant in Paterson, New Jersey. The event was the consequence of a runaway reaction. The reaction overpressurized a 2,000-gallon chemical vessel and released flammable material that ignited. Nine employees were injured.

Incident Snapshot

Field Value
Facility / Company Morton International, Inc.
Location Paterson, New Jersey
Incident Date 04/08/1998
Investigation Status The final report on this investigation was approved August 16, 2000.
Accident Type Reactive Incident
Final Report Release Date 08/16/2000

What Happened

At 7:40 p.m., workers turned on the steam supply to the kettle. They expected a routine six- to eight-hour production run of Automate Yellow 96.

The lead operator observed the kettle temperature rise rapidly. It reached 212°F by 8:05 p.m. The lead operator cut off the steam and turned on cooling water.

A few minutes later, the kettle began to vibrate as it exceeded the intended maximum processing temperature of 300°F. Liquid and gas vented from the top of the kettle as internal pressure increased.

As the temperature rose past 380°F, the rumbling increased. Workers began evacuating.

At about 8:18 p.m., accumulated pressure blew off the 18-inch metal hatch clamped to the top of the kettle. The kettle was lifted from its moorings and driven into the floor below.

A fiery stream of gas and liquid erupted through the roof of the building. Chemicals were released into the surrounding community.

Facility and Process Context

  • Morton International chemical plant in Paterson, New Jersey.
  • The 2,000-gallon chemical reactor was nearly four decades old.
  • The kettle was nine feet tall with carbon-steel walls an inch thick.
  • The production run was of Automate Yellow 96, a dye used to tint petroleum fuel products.
  • Yellow 96 was produced by the mixing and reaction of ortho-nitrochlorobenzene (o-NCB) and 2-ethylhexylamine (2-EHA).
  • The incident occurred in Building 11 (B-11), a three-floor building on the east end of the complex.
  • The third floor housed the condenser and exhaust piping leading outside to the thermal oxidizer and pressure-relief catch tank.
  • The entire K-7 process system, with the exception of the thermal oxidizer and pressure-relief catch tank, was located inside Building 11.

Consequences

  • Fatalities: 0
  • Injuries: Nine employees were injured, including two seriously. Workers’ injuries included burns, contusions, and twisted joints. Two employees were badly burned and required extended hospitalization. The lead operator and the supervisor suffered second- and third-degree burns, requiring their hospitalization in intensive care for 5 days.
  • Environmental release: Potentially hazardous materials were released into the community. The adjacent neighborhood was spattered with a yellow-brown mixture of compounds that included Yellow 96 Dye and o-NCB. Less than 10,000 gallons of contaminated firewater/stormwater reached the Passaic River, according to an estimate by Morton.
  • Facility damage: The explosion blew the hatch off the kettle, blew the inspection manway off the vessel, extruded the head gasket, twisted the kettle off its mounts, and dropped the kettle 4 feet onto the ground level below. The building’s wall panels and windows were blown out by the blast. The K-7 fire-suppression system and the B-11 fixed fire-water deluge system were damaged by the explosion. Overall, the building was still structurally sound and some of the equipment was salvageable.
  • Operational impact: The fire was reported under control at 11:27 pm. Morton collected on-site approximately 310,000 gallons of contaminated water from fire-fighting operations and next-day rain. Nearby residents were ordered to shelter in-place for approximately 2 to 3 hours.

Key Findings

Immediate Causes

  • The explosion and fire were the consequence of a runaway reaction, which over-pressured a 2000-gallon capacity chemical reactor vessel and released flammable material that ignited.
  • The reaction accelerated beyond the heat-removal capability of the kettle.
  • The resulting high temperature led to a secondary runaway decomposition reaction causing an explosion, which blew the hatch off the kettle and allowed the release of the kettle contents.

Contributing Factors

  • The reaction was started at a temperature higher than normal.
  • The steam used to initiate the reaction was left on for too long.
  • The use of cooling water to control the reaction rate was not initiated soon enough.
  • The Paterson facility was not aware of the decomposition reaction.
  • The Process Safety Information (PSI) package noted the desired exothermic reaction, but did not include information on the decomposition reaction.
  • Morton did not follow up on two recommendations made by its researchers in 1989.
  • Morton revised the process from a semi-batch process to a batch process and did not take into account that this change resulted in a potentially more thermally hazardous operation.
  • The kettle was not equipped with safety equipment, such as a quench or reactor dump system, to shut down the process in case of a runaway reaction emergency.
  • Pressure relief devices (rupture disks) were too small to safely vent the kettle in case of a runaway reaction.
  • Operating procedures required that the process run at temperatures (150 to 153°C) that were near the temperature at which the reaction could become uncontrollable (195°C).
  • In several previous instances, the operators documented on the process batch sheets that the process temperature rose at a faster-than-expected rate and exceeded the upper limit specified in the operating procedures in spite of the operators’ efforts.
  • Morton transferred the Yellow 96 process from 1000-gallon to 2000-gallon kettles and increased the amount of raw materials used per batch by approximately 9 percent without using their existing Management of Change procedures.
  • Morton did not assess the effects of these changes.
  • Half of the 6 batches made after the changes had temperature excursions.
  • The OSHA Process Safety Management (PSM) standard did not cover the Yellow 96 process.
  • Morton’s PSM program did not require adherence to a number of industry good practice guidelines for the safe management of reactive chemical processes.
  • The PHA conducted for the process and the operating procedures (batch sheets) did not address the consequences of potential deviations such as excessive heating, a runaway reaction, or the inability to provide enough cooling to maintain temperatures in a safe operating range.
  • Batch sheets did not list the actions operators should take to correct or avoid deviations.
  • Operators’ reports of significant deviations in controlling batch temperature were not acted on by management.
  • The hazards of previous operational deviations were not evaluated.
  • Morton did not follow their Management of Change procedures to review changes made in reaction kettle and batch size.

Organizational and Systemic Factors

  • Morton’s initial research and development for the Yellow 96 process identified the existence and described the two exothermic chemical reactions that can occur when the chemicals used to produce Yellow 96 are mixed and heated.
  • The Paterson facility was not aware of the decomposition reaction.
  • Morton did not perform additional tests or install the recommended safety equipment.
  • Morton did not conduct a preliminary hazard assessment when they brought Yellow 96 to production in 1990.
  • Morton did not effectively implement the requirements of its internal PSM program.
  • Management did not investigate the causes of temperature excursions.
  • Supervisors stated in interviews that high temperatures were considered a quality concern, not a safety issue.
  • Operators and supervisors stated during interviews that they had not been trained regarding the risk of a runaway exothermic reaction in the Yellow 96 process.
  • New operators were trained on-the-job by working with an experienced operator, but batches of Yellow 96 were made infrequently, and so on-the-job training was infrequent.
  • Morton did not use its management of change procedures to review the safety of these changes even though they met the definition of a change in Paterson’s PSM program.

Failed Safeguards or Barrier Breakdowns

  • The kettle cooling system could not safely control the exothermic Yellow 96 synthesis reaction.
  • The kettle was not equipped with safety equipment, such as a quench system or a reactor dump system, to stop the process to avoid a runaway reaction.
  • Rupture disks were too small to safely vent high pressure in the kettle in the event of either of the two foreseeable runaway reactions.
  • Operating procedures did not cover the safety consequences of deviations from normal operating limits, such as runaway reactions, or specify steps to be taken to avoid or recover from such deviations.
  • Training did not address the possibility of a runaway reaction and how operators should respond to avoid injury if a runaway reaction could not be controlled.
  • The Process Safety Information package did not include information on the undesired exothermic decomposition reaction.
  • The PHA conducted for the Yellow 96 process did not address the consequences of potential deviations such as excessive heating, a runaway reaction, or the inability to provide enough cooling to maintain temperatures in a safe operating range.
  • The kettle was not equipped with temperature or pressure alarms and there were no automatic shutdown devices.
  • The temperature chart recorder, which had a maximum reading of 150°C, was off scale and of no use to the operators.
  • The batch sheet provided incomplete information on how much heating the batch required.
  • There was no instrumentation that operators could use to measure the amount of steam being used or cooling water temperatures to ensure consistency of batch temperatures from batch to batch.
  • The K-7 fire-suppression system and the B-11 fixed fire-water deluge system were damaged by the explosion and did not aid fire suppression.

Recommendations

  1. 98-006-I-NJ-R01 — Recipient: Morton International, Inc. (a wholly owned subsidiary of Rohm and Haas Company) — Status: Not specified — Summary: Establish a program that ensures that reactive chemical process safety information and operating experience are collected and shared with all relevant units of the company.
  2. 98-006-I-NJ-R02 — Recipient: Morton International, Inc.’s Paterson, New Jersey Plant — Status: Not specified — Summary: Revalidate Process Hazard Analyses for all reactive chemical processes in light of the findings of the U.S. Chemical Safety and Hazard Investigation Board (CSB) report and upgrade, as needed, equipment, operating procedures, and training.
  3. 98-006-I-NJ-R03 — Recipient: Morton International, Inc.’s Paterson, New Jersey Plant — Status: Not specified — Summary: Evaluate pressure relief requirements for all reaction vessels using appropriate technology, such as the Design Institute for Emergency Relief Systems (DIERS) method and test apparatus and upgrade equipment as needed.
  4. 98-006-I-NJ-R04 — Recipient: Morton International, Inc.’s Paterson, New Jersey Plant — Status: Not specified — Summary: Evaluate the need for and install, as necessary, devices, such as alarms, added safety instrumentation, and quench or reactor dump systems to safely manage reactive chemical process hazards.
  5. 98-006-I-NJ-R05 — Recipient: Morton International, Inc.’s Paterson, New Jersey Plant — Status: Not specified — Summary: Revise operating procedures and training for reactive chemical processes as needed, to include descriptions of the possible consequences of deviations from normal operational limits and steps that should be taken to correct these deviations, including emergency response actions.
  6. 98-006-I-NJ-R06 — Recipient: Morton International, Inc.’s Paterson, New Jersey Plant — Status: Not specified — Summary: Implement a program to ensure that deviations from normal operational limits for reactive chemical processes that could have resulted in significant incidents are documented and investigated and necessary safety improvements are implemented.
  7. 98-006-I-NJ-R07 — Recipient: Morton International, Inc.’s Paterson, New Jersey Plant — Status: Not specified — Summary: Revise the Yellow 96 Material Safety Data Sheet (MSDS) to show the proper boiling point and National Fire Protection Association reactivity rating. Evaluate the need for and change, as necessary, the MSDSs for other Morton dyes. Communicate the MSDS changes to current and past customers (who may retain inventories of these products).
  8. 98-006-I-NJ-R08 — Recipient: Occupational Safety and Health Administration (OSHA) and Environmental Protection Agency (EPA) — Status: Not specified — Summary: Issue joint guidelines on good practices for handling reactive chemical process hazards.
  9. 98-006-I-NJ-R09 — Recipient: Occupational Safety and Health Administration (OSHA) and Environmental Protection Agency (EPA) — Status: Not specified — Summary: Participate in a hazard investigation of reactive chemical process safety conducted by the CSB.
  10. 98-006-I-NJ-R10 — Recipient: American Chemistry Council; Center for Chemical Process Safety (CCPS); Paper, Allied-Industrial, Chemical & Energy Workers International Union (PACE); Synthetic Organic Chemical Manufacturer’s Association (SOCMA) — Status: Not specified — Summary: Communicate the findings of this report to your membership.

Key Engineering Lessons

  • Reactive chemical processes require hazard analyses that explicitly address runaway reactions, excessive heating, inadequate cooling, and decomposition reactions.
  • Scale-up from 1000-gallon to 2000-gallon kettles and batch-size increases must be reviewed through management of change before implementation.
  • Cooling capacity, pressure relief sizing, and emergency shutdown provisions must be evaluated for the actual runaway scenarios that can occur, not only for normal operation.
  • Operating procedures and batch sheets must tell operators how to recognize and correct temperature deviations and what emergency actions to take if control is lost.
  • Instrumentation must allow operators to measure the relevant process variables, including steam input and cooling water performance, and not rely only on experience and intuition.
  • Prior temperature excursions and other significant deviations should be documented and investigated so that design and procedure problems are corrected before a catastrophic event.
  • Process safety information must include undesired reactions and other hazard data needed by operators and PHA teams to understand the full reactive hazard.

Source Notes

  • Priority 1 final report information was not provided in the extracts; consolidation therefore relies on the supporting documents at source_priority 4.
  • Where documents differed on minor details such as report timing or shelter-in-place duration, the final report extract was used when available; otherwise the most specific supporting extract was retained.
  • Recommendation IDs and exact wording were taken from the final investigation report extract where available.
  • No external facts were added beyond the provided source extracts.

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