GLENVILLE -- Schenectady County officials confirmed this week that a heating unit caused the Sept. 28 explosion and fire that destroyed a storage tank at Mohawk Asphalt Emulsions on Freemans Bridge Road.
Firefighters from several towns' departments fought the fire, which began in a fuel tank at around 6:30 a.m. An explosion heard by people in nearby residential neighborhoods preceded the blaze.
Members of the Schenectady County Fire Coordinator's Office investigated.
"The determination of the county fire investigation team was it was an accidental explosion caused by the heating unit of the tank to be left on with insufficient material in the tank for cooling," said Joe McQueen, spokesman for Schenectady County.
McQueen said the county team's purpose was to determine cause only.
"We don't go deep, deep into investigations. We don't determine who did it. We don't determine how it was done, especially in this instance when it was determined it was accidental," McQueen said.
Mohawk Asphalt Emulsions officials said last Thursday that a heater operating inside the tank caused a cleaning solution -- that contained kerosene -- to overheat and catch fire. Tony Gorman, of The Gorman Group, which owns Mohawk Asphalt Emulsions, later told Glenville officials the asphalt plant would no longer use the flammable kerosene solution that caused the explosion.
Thomas Corners Fire Chief Garth Riccio said Thursday that firefighters believe the tank contained between 5,000 and 7,000 gallons of the solution when the incident occurred.
"The biggest problem was it's volatile, and it had a flash point of 115 degrees, which is a lower flash point than gasoline," added Riccio, whose department was the lead fire agency at the scene. "So that's why it was so easy to ignite."
Riccio also said the tank was heated by natural gas.
"It was more or less like a furnace type of thing," he said. "There's a tube inside the tank, and the tube gets heated, which heats up the material, and the tube inside the tank is brick-lined."
The U.S. Occupational Safety and Health Administration also is investigating the explosion and fire.
"They probably will not comment on the inspection because it is still open," OSHA spokesman James Lally said earlier this week.
The explosion was the second at Mohawk Asphalt Emulsions in less than a year. On Oct. 17, 2016, a tanker truck exploded at the plant and severely burned two men who later died from their injuries. A third man also was hurt in the explosion.
Reach Gazette reporter Jeff Wilkin at 518-395-3124 or at [email protected] at @jeffwilkin1 on Twitter.