At least 5 dead in CT power plant explosion

MIDDLETOWN, Conn. (WTNH) - The Middletown, Connecticut mayor's office is now saying at least 5 people are known dead in a Connecticut power plant explosion.

The explosion happened at the Kleen Energy natural gas and oil plant under construction on River Road around 11:30 a.m.

Here are the latest details that  WTNH has learned from authorities at the command post:

-50 workers believed in the building today
-This was a working construction site
-Workers were doing a 'blow down' to clear gas from the lines when the explosion occurred
-No word on where the workers are from
-Fire is completely out
-State Police Major Crimes Squad on the scene, with many other state, local agencies
-Ambulances leaving area without lights or sirens on
-Local residents told to stay away
-Windows at Conn Valley Hospital in Middletown broken out by the explosion

Two LifeStar helicopters were called to the scene. One has taken off carrying one patient. We do not know any details about the person's injuries.

Connecticut State Police have deployed detectives and cadaver dogs to the scene to help Middletown authorities, state police spokesman Lt. J. Paul Vance said.

Bernadette Nyland was outside in her yard with her dogs when she heard the blast. "They were doing the firing of the engines this morning and so something went wrong and it blew up and flames came shooting up almost as tall as that stack," she said.

There are reports that homes near the plant have been damaged by the explosion. It was felt as far away as Wallingford, North Haven, North Branford and Cheshire, Connecticut.

WTNH reporter Darren Kramer said on Twitter he was outside in North Guilford when he heard the explosion. "Sound was huge and low. Lasted several seconds. Assumed sonic boom."

Another Twitter follower named Jennifer said via Twitter, "First thought was earthquake or huge gust of wind--whole house shook, very brief but powerful"

Others heard or felt the explosion in Oxford and as far away as Mystic.

Dozens of emergency personnel from multiple towns and agencies are on the scene.

Hospitals in Middletown and Portland went into disaster/mass casualty modes in the hours after the explosion.

Middlesex Hospital, which had been in a disaster mode, is now scaling back from its disaster plan. They are not treating burn victims, but patients have injuries to extremities, such as broken bones. WTNH reporter Sara Welch said one patient with a head injury was transported to Hartford Hospital.

Bridgeport Hospital, which has a burn center, is on standby, but a spokesman says they have not yet been alerted that any patient is heading their way.

Governor Jodi Rell was on her way to the scene. A statement from her office said "Governor Rell has activated the Emergency Operations Center in Hartford and is being staffed by:

the state Department of Emergency Management and Homeland Security (DEMHS), Department of Public Health (DPH), the National Guard and the State Police. DPH is providing tents at the scene for shelter and medical triage

The Governor has also activated the Urban Search and Rescue Team. "