A Bovis Lend Lease site manager has been charged along with two others and a subcontracting firm over the death of firefighters killed in a blaze at New York's Ground Zero.

Robert Beddia, 53, and Joseph Graffagnino, 33, both died battling a fire on 18 August 2007 at the former Deutsche Bank building, which was scheduled for demolition after being damaged in the September 11 terrorist attacks.

Indicted on manslaughter charges are demolition subcontractor John Galt Corporation, Bovis site safety supervisor Jeffrey Melofchik, Galt executive Mitchell Alvo and Galt foreman Salvatore DePaola.

All defendents have pleaded not guilty but could face jail sentences of 15 years if convicted.

Main contractor Bovis escaped any charges.

Announcing the charges this week, Manhattan District Attorney Robert Morgenthau said regulations had been overhauled: "It's amazing the number of mistakes made. That's why we made a special effort to change the whole environment."

Civilian inspectors will be added to the Fire Department to monitor buildings being built and demolished, while Bovis promised to add staff and train workers in fire safety and establish a US$10m fund for the firefighters' families.

The deadly blaze was started by a discarded cigarette on the building's 17th floor and raged out of control quicky.

Firefighters in attendance had trouble with water supply as they did not realise a key water pipe supplying the building had been cut.

The pipe, originally held in place by hangers attached to rods hanging from the ceiling, was hard to clean so supervisors sawed off the rods, letting part of the pipe break away.

"As a result, firefighters rushed into the building with no idea of the obstacles they would face in fighting the fire," Morgenthau said.

Morgenthau also blasted the city building department for failing to enforce contractors' compliance with rules. Inspectors never went to the basement and looked at the break in the water pipe and didn't make sure stairwells were cleared.