A propane tank caused an explosion July 18 at Fraser, Mich.-based Product and Tooling Technology Inc.'s headquarters.
The company, which does business as PT Tech, offers tooling, rapid prototyping and low-volume production.
Video from inside the building showed the propane tank on a forklift caused the blast, Fraser Department of Public Safety interim Director Mike Pettyes told Plastics News.
"All of the walls" of the PT Tech facility were knocked down except one "explosion-proof" wall on its west side that was not impacted, Pettyes said.
"With what it did to the building, we're looking into if possibly there were any other factors involved," he said. "We're kind of scratching our head at the amount of damage from that propane tank."
No one was inside the building when the explosion occurred at 7:15 a.m., Pettyes said, and no injuries were reported.
An investigation to further clarify the cause of the explosion by the Michigan State Police; the Bureau of Alcohol, Tobacco, Firearms and Explosives; and city of Fraser detectives is still underway, he said.
PT Technology did not immediately respond to requests for comment by Plastics News. According to the company's website, it was founded in 1996 and makes tooling for injection, blow and compression molding. Its plastics processing capabilities include thermoforming, reaction injection molding and composite manufacturing.