The Fire Department's Engine 2 responded to a call about a small, outdoor fire underneath a tarp at 4:40 p.m. in the parking lot at 2278 Black Rock Turnpike, between Uno's of Chicago and the building where Trader Joe's is located.

Upon arriving at the scene, personnel from Engine 2 noticed the fire originated from two buckets of chemicals and then contacted the state's HazMat team, the Fire Department report states. Prior the HazMat team's arrival, Engine 2 extinguished the fire with carbon dioxide because putting it out with water could have exacerbated the chemical reaction.

Matt Williamson, the DEP's supervising emergency response coordinator, arrived at the scene around 5:30 p.m. He explained that the two buckets of chemicals being used for roof construction at 2278 Black Rock Turnpike became overheated from sitting under a tarp in the heat. The roofing contractors had used a two-part apoxy of chemicals, Williamson said.

The first container exploded onto the second container and the HazMat team had to stabilize the chemicals before they mixed and potentially exploded, said Rachel Sunny, a spokesman for the DEP.

The first part was a 5-gallon bucket with 17 pounds of organic peroxide, Williamson said. Sunny said the organic peroxide should be stored at temperatures lower than 77 degrees Fahrenheit, but it overheated on that hot afternoon. The second vat of chemicals was a 22-gallon metal container containing flammable material, Williamson said.

The company in Arkansas that manufactures the roofing chemicals was contacted and asked what the chemicals were capable of doing if the overheated organic peroxide mixed with the other flammable material, Williamson said. However, the company's scientists said they did not know what could happen, so the HazMat team decided to prepare for the "worst case scenario," said Williamson, because "anytime you're dealing with [organic peroxides] you should use the utmost caution."

The building owner, Lawrence Roberts, arrived at the scene, as did representatives from the roofing company, F.J. Dahill Company Inc. of New Haven. However, Dahill "cooperated fully in resolving the situation," Williamson said. Dahill was unavailable for comment before press time yesterday.

According to the Fire Department report, Uno's of Chicago was evacuated by midnight, which manager Rich Cardone said is about an hour and a half earlier than employees usually leave on a weekend night. Restaurant patrons knew what was going on in the parking lot because there were several fire trucks, but no one was panicking, Cardone said.

"I wasn't so nervous about it," Cardone said. "I felt pretty confident in the Fairfield Fire Department that my building would be there in the morning."

Most other Black Rock Turnpike businesses already were closed at that time of night. Police blocked off Black Rock Turnpike from Fairfield Woods Road to Stillson Road. Fire Chief Richard Felner said area residents were not warned of the potential explosion because the Fire Department did not want anyone to unnecessarily panic.

After midnight, with the businesses empty, the HazMat team then attempted to stabilize the chemicals in order to remove them. Williamson said emergency responders did not want to risk sending someone in a HazMat suit to remove the chemicals physically because a suit may not have been protection from an explosion.

According to the Fire Department report, emergency personnel set up a sand berm around the site for protection. Then, an unmanned water cannon from Engine 2, connected to a hydrant on Fairfield Woods Road, was sprayed on the product to determine shock sensitivity, or the potential for explosion. "DEP felt that product was not shock sensitive, apparently due to burnoff of polymerizing ingredients," the report states. The chemicals were then removed.

Fire Department and HazMat personnel left the scene after 2 a.m. Sunday.