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US Ink Fire

Overview

An explosion and flash fires occurred at the US Ink manufacturing facility in East Rutherford, New Jersey. Seven workers were injured. According to the final report, workers gathered at the entrance to the pre-mix room after hearing a loud thump from the newly installed dust collection system and seeing signs of an initial flash fire from the bag dump station. A second flash fire then occurred and flashed over the assembled workers.

Incident Snapshot

Field Value
Facility / Company US Ink/Sun Chemical Corporation
Location East Rutherford, NJ
Incident Date 10/09/2012
Investigation Status The CSB issued its final report at a public meeting in East Rutherford, NJ, on January 15, 2015.
Accident Type Combustible Dust Explosion and Fire
Final Report Release Date 01/15/2015

What Happened

  • On Friday, October 5, 2012, the new dust collection system for the pre-mix room was commissioned for service and operated until the end of the production shift at 3:00 pm EST.
  • On Saturday, October 6, 2012, plant maintenance employees used housekeeping connections on the new dust collection system to vacuum dust and debris in the pre-mix room.
  • A maintenance employee manually shut down the dust collection system after it ran all night.
  • US Ink/Sun Chemical Corporation management took no action to immediately investigate the failure or to shut down the ink mixing operation until the malfunction was corrected.
  • Employees restarted the mixing tanks and the dust collection system on the Monday night shift, October 8, 2012.
  • On Tuesday morning, October 9, 2012, black ink production continued, with batches being run in all three mixers.
  • At about 1:00 pm, the pre-mix room operator was loading Gilsonite into the bag dump station when he heard a strange squealing noise from T-206.
  • The operator saw a flash fire originating from the bag dump station.
  • Workers congregated at the entrance to the pre-mix room in response to the flash from the bag dump station and the subsequent loud thump.
  • After about 2 minutes, seven workers observed an approximately 1-foot flame directly over T-306.
  • The flame then gained additional energy from the powdery mixture of accumulated carbon black, Gilsonite, and clay in the ductwork of the dust collection system.
  • The mixture acted as fuel, and the fire flashed over the assembled workers in the doorway of the pre-mix room.

Facility and Process Context

  • US Ink is an ink manufacturer established in 1993 through the merger of U.S. Printing Ink and the News Ink Division of Sun Chemical Corporation.
  • The East Rutherford facility had 34 employees, and 28 employees were on shift at the time of the incident.
  • The plant manufactures both black and color oil-based ink for various commercial clients.
  • The pre-mix room is 30 feet wide by 17 feet deep and has cinder block walls up to the 30-foot ceiling height.
  • The bag dump station was positioned in the doorway of the pre-mix room.
  • An overhead rollup service door was installed for access to the pre-mix room and was chained into a fixed rolled-up position to provide easier entry into the room.
  • The company added three housekeeping connections, not included in the initial design, to the vacuum system of the dust collection system for operator use in picking up dust and other debris in the pre-mix room.
  • The dust collection system was commissioned at the facility in the week preceding the incident.
  • The flash fire occurred in the dust collection system during the first day of normal production after initial equipment start-up.

Consequences

  • Fatalities: None reported.
  • Injuries: Seven workers suffered burn injuries, including three who sustained third-degree burns.
  • Environmental Release: None reported.
  • Facility Damage: Equipment in the pre-mix room, including ductwork, motors, electrical cables, and conduit, sustained extensive thermal damage. Portions of the dust collection ducting were separated, and at least one housekeeping connection end cap blew off. Extensive smoke and dust deposits accumulated on the structure and equipment surfaces in the hallway and around the pre-mix room. The incident caused no apparent structural damage to the building.
  • Operational Impact: After the incident, production was suspended pending internal and external investigation by the company, OSHA, and CSB. Some production of colored inks resumed about a week later, but black ink production was halted until the end of December.

Key Findings

Immediate Causes

  • The explosion and flash fires occurred because of continuous manually controlled heating of the mixing tanks and operation of the dust collection system for several hours after commissioning, with the system continuing to draw condensable vapors into the duct.
  • Continuous operation of the dust collection system led to self-heating and spontaneous self-ignition of the accumulated sludge-like material and the powdery dust mixture of Gilsonite, carbon black, and clay in the ductwork above T-306.
  • Transport of the burning sludge to the dust collector caused the dust collection explosion.
  • The residual flame ignited the dispersed dust, and the subsequent fireball dislodged and lifted more dust so that an expanding fireball vented through the doorway into the corridor.
  • This expanding fireball, or flash fire, was responsible for the multiple burn injuries.

Contributing Factors

  • The dust pickup points in the dust collection system pulled excessive quantities of dust and condensable vapors into the ductwork, which operated at low conveying velocities.
  • Dust pickups at mix tanks pulled air through the tank headspaces and extracted excessive quantities of condensable vapors and dust into the duct mains.
  • Dust loading from housekeeping dust pickups with insufficient makeup air.
  • Duct blockage because of failure to consider the effect of condensable vapors in the ductwork.
  • Blockage of the Dust Collector Dust Fines Chute because of design failure.
  • Duct main blockage from low conveying velocity.
  • Ineffective system checkup at commissioning of the dust collection system.
  • Lack of system controlling parameters for operators to monitor performance and detect system degradation.
  • Dust collection system that was not designed to prevent and contain fires or extinguish fires.
  • The addition of three housekeeping hoses to the system contributed additional dust to the main ductwork, but not the makeup air needed to convey the additional dust to the dust collector.
  • The design of ductwork for the dust collection system did not reflect consideration of the presence of condensable vapor generated by the high temperature of the ink mixing process.
  • The dust collector dust hopper and dust fines chute were filled with approximately 322 pounds of dust fines in just 2 days of system operation.
  • The duct main had insufficient conveying velocity until the three-way junction where the bag dump branch and the duct-mounted air bleed joined the duct from the three mix tanks and the housekeeping system pickups.
  • The rubberized flexible hoses were the first part of the system to fail when the duct fire started.
  • The absence of duct cleanout doors.
  • Ducts with cross-sections larger than 75 square inches did not have an automatic fire extinguishing system.
  • The Fike chemical suppression and isolation system attached to the dust collector stopped an explosion, but it was not designed to extinguish fires.
  • The new dust collection system actually continued to run overnight, even when all the ink mixers were shut off.
  • US Ink/Sun Chemical Corporation management took no action to immediately investigate the failure or to shut down the ink mixing operation until the malfunction was corrected.
  • The pre-mix room operator did not shut down the mixing operation and the dust collection system from the control panels near the pre-mix room.
  • The system did not produce an audible alarm.
  • The employees were not wearing flame-resistant clothing (FRC).

Organizational and Systemic Factors

  • The lack of adequate oversight by Sun Chemical Corporation management personnel in the planning, design, installation, and commissioning of the dust collection system likely contributed to the October 9, 2012, incident.
  • Inadequate project oversight.
  • Ineffective employee training on the dust collection mechanism.
  • Failure to develop and implement corrective actions from a previous incident.
  • US Ink/Sun Chemical Corporation did not perform onsite risk and hazard assessments before start-up of the new dust collection system.
  • No onsite inspection or measurement of system performance parameters, such as airflow rate and conveying velocity, was conducted to ensure that the system was working appropriately.
  • US Ink/Sun Chemical Corporation lacked an adequate and effective process for management of organizational change.
  • No procedures allowed for transferring and retaining design knowledge and forwarding information to the new engineer.
  • US Ink/Sun Chemical Corporation did not provide additional contractor oversight for the dust collection project.
  • The 15-minute meeting on October 5, 2012, was less than adequate.
  • The meeting did not include information on how the dust collection system was designed to work and how operators could troubleshoot problems.
  • US Ink did not develop a fire or explosion incident prevention program to reinforce employee understanding of the potential hazard severity associated with the newly installed dust collection system.
  • No mechanism was in place for pre-mix room operators to determine changes in dust collection system performance.
  • US Ink did not address any lessons learned from the February 29, 2008 incident.
  • The company did not install temperature indicators and temperature interlocks that would activate when the temperature from the ink mixing operation became too high.
  • US Ink/Sun Chemical Corporation did not obtain building, fire, or electrical permits for the construction and installation of the new dust collector.
  • US Ink did not submit an inquiry to the local building department to determine whether a construction permit for the new dust collection system was necessary.
  • The East Rutherford Building Department does not have a strict permit, code notification, and enforcement process to ensure compliance with the New Jersey UCC.

Failed Safeguards or Barrier Breakdowns

  • The automatic shutoff did not engage as designed once the system was energized and thus had to be manually turned off and on by US Ink maintenance employees and pre-mix room operators.
  • The dust collection system was designed to start automatically when any of the mixing tank motors was energized and automatically shut off when all mixers were inactive, but it continued to run overnight.
  • The dust collection system did not have local static pressure devices near the mixing tanks or the bag dump hood.
  • None of the pressure gauges displayed action limit information.
  • No pitot tube holes were visible in the ducts, indicating that no system pressure measurements were taken at commissioning.
  • US Ink/Sun Chemical Corporation did not perform any of the required system test activities after installation of the dust collection system.
  • The dust collection system was not systematically monitored and maintained; no processes were in place to detect the duct plugging that occurred.
  • The sprinkler system was activated after the second flash event.
  • The explosion suppression system did not produce an audible alarm.
  • The manual alarm notification system that US Ink adopted was ineffective on the day of the incident.
  • No other automatic fire alarm system was located anywhere in the US Ink East Rutherford facility.
  • The Fike explosion suppression and isolation system prevented the structural failure of the dust collector by suppressing the deflagration and isolating the dust collector as designed.
  • The dust collection system had no cleanout doors.
  • The dust collection system was not designed to prevent, contain, or extinguish fires.
  • The employees were not wearing flame-resistant clothing (FRC).

Recommendations

  1. 2006-01-I-H R1 — Recipient: U.S. Occupational Safety and Health Administration — Status: Reiterated recommendation — Summary: Issue a standard designed to prevent combustible dust fires and explosions in general industry. Base the standard on current National Fire Protection Association (NFPA) dust explosion standards, including NFPA 654 and NFPA 484, and include at least the following: Hazard assessment; Engineering controls; Housekeeping; Building design; Explosion protection; Operating procedures; Worker training.
  2. 2013-01-I-NJ R1 — Recipient: U.S. Occupational Safety and Health Administration — Status: Open — Summary: Add North American Industry Classification System (NAICS) Code 325910, Printing Ink Manufacturing, to the list of industries in Appendix D-1 or Appendix D-2 of Combustible Dust National Emphasis Program (NEP), Directive CPL 03-00-008.
  3. 2013-01-I-NJ R2 — Recipient: U.S. Occupational Safety and Health Administration — Status: Open — Summary: Communicate with all OSHA Area Offices to encourage appropriate application of the following existing provisions of the Combustible Dust NEP, Directive CPL 03-00-008: Paragraph IX, Section A2, and Paragraph IX, Section B4.
  4. 2013-01-I-NJ R3 — Recipient: NEW JERSEY DEPARTMENT OF COMMUNITY AFFAIRS — Status: Open — Summary: Revise the exemption for “manufacturing, production, and process equipment” under the New Jersey Uniform Construction Code (N.J.A.C 5:23-2.2) to require that equipment involved in processing, handling, or conveying combustible dust comply with the design and operating requirements of the current edition of the International Building Code.
  5. 2013-01-I-NJ R4 — Recipient: NEW JERSEY DEPARTMENT OF COMMUNITY AFFAIRS — Status: Open — Summary: Develop and implement training for local code officials on the National Fire Protection Association (NFPA) standards referenced in the New Jersey adoption of the International Building Code (IBC) for occupancies with a high hazard classification (Group H); specifically, include training on equipment that handles combustible dust and the hazards involved.
  6. 2013-01-I-NJ R5 — Recipient: NEW JERSEY DEPARTMENT OF COMMUNITY AFFAIRS — Status: Open — Summary: Promulgate a regulation that requires all occupancies handling hazardous materials to inform the local enforcement agency of any type of construction or installation of equipment at an industrial or manufacturing facility. Also require local enforcement agencies to evaluate the information to determine whether a construction permit is required.
  7. 2013-01-I-NJ R6 — Recipient: US INK/SUN CHEMICAL CORPORATION — Status: Open — Summary: At the US Ink East Rutherford facility, install automatic fire alarm systems consistent with NFPA 72, the National Fire Alarm Code, in manufacturing areas such as mixing where heat generation could occur.
  8. 2013-01-I-NJ R7 — Recipient: US INK/SUN CHEMICAL CORPORATION — Status: Open — Summary: Revise the Capital Appropriations/Asset Request (CAR) form procedure for new installations and modifications to existing equipment to require at a minimum the following: Process hazard analysis (PHA); Management of change (MOC); Review of engineering drawings for permits; Safety management of contractors; Training of plant operators based on applicable dust collection system guidelines and standards, including NFPA 91 and NFPA 654.
  9. 2013-01-I-NJ R8 — Recipient: US INK/SUN CHEMICAL CORPORATION — Status: Open — Summary: Develop and implement a management of organizational change protocol to allow for the transfer of knowledge and information to new personnel, at a minimum including initial and refresher training in the following: Safety and health procedures; Lessons learned from previous incidents; Technical information for equipment; Routine plant operation.

Key Engineering Lessons

  • Dust collection systems handling combustible dust and condensable vapors must be designed with sufficient conveying velocity and airflow to prevent accumulation in ductwork.
  • Housekeeping connections or hoses added to a dust collection system must be evaluated for their effect on dust loading and makeup air requirements.
  • Commissioning must include testing and measurement of system performance parameters such as airflow rate, conveying velocity, and pressure.
  • Dust collection systems should be designed to prevent, contain, or extinguish fires, and not rely solely on explosion suppression and isolation.
  • Changes to equipment function, such as adding housekeeping capability to a dust collection system, require process hazard analysis and management of change review.
  • Operators need clear system controls, alarms, and action limits to detect degradation and abnormal conditions before plugging or ignition occurs.
  • Design and installation oversight must verify that the as-built system matches the intended design and that contractors understand the process hazards.
  • Fire protection and alarm provisions should be provided in manufacturing areas where heat generation could occur.

Source Notes

  • Priority 1 final report used as the primary authority for incident facts, causes, consequences, and recommendations.
  • Priority 3 recommendation status summaries were used to confirm later recommendation closure statuses and related regulatory context.
  • Priority 4 supporting documents were used only where they added detail consistent with the final report; conflicts were resolved in favor of the final report.

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