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OSHA News Release – Region 1
U.S. Department of Labor
Region 1 News Release: BOS 99-186
Wednesday, October 6, 1999
Contact: John M. Chavez
PHONE: (617) 565-2075
JOINT INVESTIGATIVE REPORT ON JAHN FOUNDRY EXPLOSION RELEASED
A joint investigative report on the origin and cause of the February 25, 1999, explosion at the Jahn Foundry in Springfield, Massachusetts, has been released by the U.S. Labor Department's Occupational Safety and Health Administration (OSHA).
According to Ronald E. Morin, OSHA area director in Springfield, the Joint Foundry Explosion Investigation Team (JFEIT) was composed of OSHA, the Massachusetts Office of the State Fire Marshall, and the Springfield Arson and Bomb Squad.
He noted that these three agencies proactively undertook a cooperative, joint investigation into the cause of the explosion and fire, which extensively damaged several buildings in the Jahn Foundry complex and seriously injured twelve employees. Three of the most severely burned employees subsequently died from their injuries.
"Our goal," Morin said, "was to determine as best we could the conditions which existed in the foundry prior to the explosion, and the events leading up to this catastrophic accident in order to prevent anything like this happening again. It is hoped that the release of this report on the findings of the joint investigation will allow other foundry facilities across the country to assess their own situations and apply the lessons learned here in time to prevent a similar tragedy."
He noted that the investigation determined that an initiating fire event in one of the Shell Mold stations in the Shell Mold Building was pulled into the exhaust ventilation system. The interior of the ductwork of that system was heavily loaded with deposits of phenol formaldehyde resin, an explosive organic dust. The ignition of this dust caused a turbulent fire and explosion(s) which traveled through the interior ductwork and in turn shook down explosive concentrations of combustible resin dust that had collected on surfaces throughout the Shell Mold Building. When the fire exploded out from the ductwork, it ignited these airborne concentrations of combustible dust, causing a catastrophic dust explosion which lifted the building's roof and blew out its walls.
The report notes that, although it was not possible to conclusively determine the initiating event which caused the resultant dust explosion, a number of plausible scenarios were developed from the physical and testimonial evidence. Of these, the following two were determined to be the most probable:
- Dust Scenario: Heavy deposits of resin dust were found in the flexible exhaust ducts serving the ovens in the shell molding stations. The open ends of the ducts were placed adjacent to the ovens, at approximately head level, and in an area where employees must present themselves to deal with the ovens. Jarring of the duct readily dislodged the deposits of dust. In this scenario, jarring of the duct caused dust to fall down onto the oven and be ignited. The resulting fireball was then pulled back into the flexible duct where it started the turbulent fire and explosions in the exhaust ventilation system.
- Gas Scenario: The fuel trains to the ovens in the shell molding stations were found to be in very bad condition. The internal mechanisms of the valves controlling the flow of combustion air and natural gas to the ovens were found to be massively contaminated with resin and sand. The proper functioning of these valves was critical for providing air and gas to the ovens in the correct ratio to support combustion. Oven flameouts were a recurrent problem. The ovens were not provided with a flame-sensing device to prevent the flow of gas to the oven in the absence of main flame. Although a switch and thermocouple prevented the flow of gas to the oven in the absence of a pilot flame, the pilot flame was not able to light the burners. Thus, in the absence of a main flame, gas could continue to flow to the oven. In this scenario, gas was flowing to an oven that was not lit. The unburned gas collected in sufficient quantities to finally be ignited by the pilot or other ignition source, and the resulting fireball was pulled into the flexible duct where it started the turbulent fire and explosions in the exhaust ventilation system.
The report found that inadequate housekeeping, ventilation, maintenance practices and equipment were all causal factors for the initiating and catastrophic events.
Morin stated that copies of the 56-page report are available by contacting either his office (OSHA) in Springfield at 413-785-0123 or the Regional Public Affairs Office of the U.S. Department of Labor in Boston at 617-565-2072.
The information in this release will be made available to sensory impaired individuals upon request. Voice phone: (617) 565-2072. TDD (Telecommunications Device for the Deaf) Message Referral Phone: 800-347-8029.
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