An investigation into an explosion last year at a fertilizer plant has been completed by the State Fire Marshal’s Office and the report reads like a classic flammable liquid explosion – one small problem, Triclopyr 3 is not a flammable liquid! Triclopyr 3 has a flash point of 141°F and in today’s GHS world that makes this liquid a Category 4 flammable liquid, or as we used to call it – a combustible liquid. Here’s more…
At about 7:25 a.m. Aug. 8, 2015 (e.g. a hot day, but not 141ºF hot) the County Sheriff’s Office received multiple calls reporting an explosion at the plant. The Fire Department responded and a large hole was found in the roof of a building, which the report stated the commercial building is a single story with a three-layer metal roof. In previous reports, company officials said it was a bulk tank storage facility.
Firefighters entered the building and found no one inside and no signs of fire. The report noted that the structure had a fire alarm system, sprinkler system, and heat detectors, and the sprinkler system activated from the explosion. Two minor injuries were reported in connection to the incident; one person was transported to a hospital and another visited a local doctor. The report stated the person transported said it was due to a blood pressure issue resulting from the traumatic experience.
The investigation report from the State Fire Marshal’s Office states the point of origin of the explosion was inside the Triclopyr 3 storage tank that was inside the metal building. The ignition source, ignition sequence and first material ignited could not be determined, according to the report.
The report does list four factors that could have contributed to the explosion:
- the trailer offloading the chemical was not grounded, which was required for the process; (NOTE: we actually “bond” the trailer to the piping system)
- the intermodal tank was improperly vented during the unloading process; (NOTE: this technically would not be a contributing factor to an explosion in the storage tank)
- a centrifugal pump was used that was not made to handle flammable materials as per the manufacturer’s instructions;
- a sensor system which measures the amount of liquid in the storage tank had paperwork stating it should not be used in a hazardous location
In interviews with people at the scene, the report stated the driver of the truck with the intermodal tank trailer arrived at the facility at about 7 a.m. to offload the chemical. The investigator did not observe any visible grounding connections between the trailer and facility. Company policies and procedures indicated the truck was to be grounded before offloading the Triclopyr 3. About 2,956 gallons of the chemical was offloaded into the tank inside the building before the explosion.
Several witnesses reported to the investigator of hearing two explosions, and a few employees reported they were knocked off their feet. From the employee interviews, the investigator found that the Triclopyr 3 pump used to offload the chemical was recently replaced. It was the second time that pump was used. The manual and the pump itself had a warnings listed that it was not to be used with flammable liquids. The warning also stated that doing so could result in an explosion. The report noted that Triclopyr 3 is considered a flammable liquid.