Date of incident: November 2019
Notice of incident number: 2019139860093
Employer: Non-alcoholic beverage manufacturer

Incident summary
After business hours at a juice manufacturing plant, a worker was doing paperwork upstairs and overseeing production processes. The worker started the pasteurization process after all other workers had left for the day. While the worker was in an upstairs office, a fire started in the compressor room, on the upper floor of the plant. The worker was exposed to products of combustion during the three-alarm fire and sustained fatal injuries. No other workers were injured.

Cause

• Oil leaked down water tank and was ignited by gas burners. Several years before the incident, a gas-fired hot water heater (in the compressor room) had been converted to heat oil for the pasteurization system. The natural gas burner unit attached to the bottom of the tank was not fully enclosed. The water heater had a leak at the top of the tank, and hot oil ran down the tank under the insulation to the gas burners, where the oil ignited.

Contributing factors

• Equipment was modified against manufacturer’s specifications. The conversion of the gas-fired water heater to an oil heater was against the manufacturer’s specifications as the hot water heater was rated and certified for heating water only. Approximately two years before the incident, a mechanical contractor had advised the employer that this was not a safe way to heat oil, but the employer did not replace the modified hot water heater.
• Electrical crankcase heater increased temperature of oil. An electrical crankcase heater was located at the base of the water heater, near the gas burners. Investigators believe this crankcase heater was installed so that the oil would heat faster once the gas was ignited, to achieve the required high temperature for the juice pasteurization. The crankcase heater could have increased the temperature of any leaked oil to (or close to) the flashpoint and fire point of the oil.
• Melted quick-clamp connections provided fuel. Directly above the gas burners — on the lines running to and from the water heater — were quick-clamp connections that required gaskets to seal. After the incident, these connections were loose, and investigators believe that the gaskets had melted. Once the quick-clamp seal in close proximity to the early fire melted, there would have been a substantial supply of oil to fuel the fire.
• Additional fuel and oxygen were readily available. A bucket containing oily rags was stored in the compressor room and could have provided fuel in the early stages of the fire. The fire damage to the walls of the compressor room indicated that the fire had sufficient energy to enter the walls and, in some locations, burn the wood studs in the walls, which provided more fuel for the fire. In addition, a container of combustible material stored in the compressor room and lines containing glycol that ran through the wall to the adjacent tanks in the production room may have provided fuel for the fire. The room where the fire occurred was not closed off, and therefore a supply of oxygen was readily available to sustain the fire.

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