JACKSONVILLE, Fla. (AP) -- The T2 Laboratories explosion that killed four and injured 32 in December 2007 was likely caused by an inadequate cooling system and a system that couldn't contain an out-of-control chemical reaction, a federal agency reported Tuesday.
The U.S. Chemical Safety Board also said although the plant was owned by a chemical engineer and chemist, neither had an educational background on reactive chemicals and "were unaware of the potential for a runaway accident," board Chairman John Bresland said at a news conference.
"We hope our findings once again call attention to the need for companies to be aware of how to control reactive chemical hazards," Bresland said.
Plant employees were making a gasoline additive when a chemical reaction went out of control, raising the pressure inside the reactor, causing a massive explosion and chemical fire.
The powerful blast -- which investigators said had the power of 1,400 tons of TNT -- on Dec. 19, 2007, killed four T2 employees, including one of its owners, and destroyed the company. Debris from the reactor was found up to a mile away. Four nearby businesses were damaged beyond repair.
About 1:23 p.m., the owners of the plant were called and told to return to because the plant had a cooling problem.
Upon returning, one of the owners went to the control room to help and the other went to find a mechanic. A few minutes later at 1:33 p.m., the reactor burst and its contents exploded, killing the owner and process operator, who were in the control room, and two outside operators who were leaving the reactor area.
"The CSB determined insufficient cooling to be the only credible cause of the accident, which is consistent with witness statements that the process operator reported a cooling problem shortly before the explosion," the report said.
T2 had also experienced overheating problems at the lab before the explosion.
"Although the owner/engineer told employees he thought a fire would occur, none of the T2 employees appreciated the potential for a catastrophic explosion," the report stated.
T2 never reopened after the explosion, and last month its owners filed papers to legally dissolve the company.
One of the founders, Robert Scott Gallagher, was killed in the explosion. His partner, Marion "Mike" Wyatt, 50, died Sept. 1.
Bresland said the safety board is asking the American Institute of Chemical Engineers and the Accreditation Board for Engineering and Technology to add chemical reactive hazard awareness to chemical engineering course work for students pursuing bachelor's degrees.
Agency spokeswoman Hillary Cohen said the safety board's investigation was designed to find ways to prevent similar accidents. The agency doesn't have power to write citations or order fines, but it can suggest steps that companies, industry groups and other agencies can take to improve safety.