Investigators race snow to find clues

Middletown, Conn. (WTNH) - Investigators will be back out at the scene of the Middletown plant explosion this morning sifting through the rubble to look for the cause of the blast. The upcoming snow won't help in finding answers. Check the forecast here.

Five people were killed and another 12 were injured in Sunday's explosion at the Kleen Energy power plant.

Names of the men killed in Sunday's blast.

This was already a very tricky scene for investigators, with parts of the building unstable and shifting piles of rubble. There are also acetylene tanks buried in there.

"There are certain locations that have not yet been searched," Middletown Mayor Sebastian Giuliano said Monday. "The Major Crime Unit of the State Police is mapping the blast site. Other hazards are being removed from the building."

When you add into that the threat of having all their evidence under a blanket of snow Wednesday morning, and a 72-hour search warrant acting as a ticking clock on everything, that makes it a lot tougher.

"Although intentional criminal acts have been ruled out, we have not ruled out criinal acts of negligence and therefore, until that search warrant has expired, it is a crime scene and is treated as such," Acting Deputy Chief Patrick McMahon said.

The Associated Press reports sources say a welder's torch may have been going during the tests of the gas lines on Sunday morning.

The state police will be leading the investigation, along with the Bureau of Alcohol, Tobacco, Firearms and Explosives ( ATF ) and Occupational Safety & Health Administration ( OSHA ). Investigators began arriving before dawn at the checkpoint leading to the plant site.

"For the people who lost loved ones or have been injured, this is not going to be a distant memory," Mayor Giuliano said. "Lives are changed forever and that is who we are thinking about right now."

Along with the local and federal investigation, Governor Rell is launching an investigation into the origin of the explosion and looking at safety issues and safety codes.