The owners and general contractor at the Kleen Energy power plant ignored basic safety precautions before the February blast that killed six workers and injured several dozen more, a group of lawyers said Thursday as they announced nine new lawsuits against three companies.

The lawsuits were brought by the families of three of the dead workers — Peter Chepulis, 48, of Thomaston; Kenneth Haskell, 37, of New Durham, N.H.; and Chris Walters, 48, of Florissant, Mo. — and by six of the injured — Dervan Malcom, Joshua Campbell, Brian Hawley, Joseph Scovish, Kenneth Meloney, and Dennis Riley.

The suits name Kleen Energy Systems LLC, the owners of the $1 billion plant; O&G Industries of Torrington, the general contractor; and Bluewater Energy Solutions of Atlanta. These were the firms responsible for the dangerous "gas blow'' procedure, a pipe cleaning method in which natural gas was forced through the pipes at a tremendous pressure, the lawsuits said.

The gas, inexplicably vented out of a pipe that pointed horizontally into a courtyard rather than straight up like a chimney, pooled in the bowl-like yard and was ignited by welding torches, heaters, defrosters or any number of other ignition sources, the lawsuits charged.

The three companies and other contractors were fined $16.6 million in August by federal work safety regulators, who noted 119 safety violations at the plant on Feb. 7, Super Bowl Sunday.

One of the lawyers had a blunt assessment of how the families and the workers are coping: Some of them aren't.

"They are unable to deal with this,'' said attorney Robert Reardon of New London, who represents Scovish, Meloney and Riley. "They lost friends. They are overwhelmed.''

The families of the dead are struggling to move on after losing, in many cases, the family anchor and main bread-winner, said attorney James Bartolini of Hartford.

"They are warmed by the outpouring of support from citizens,'' Bartolini said.

Lawyers M. Hatcher Norris of Hartford, who represents Chepulis' family, and John Jay Pavano of Bloomfield, who represents Hawley, joined the other two firms in an unusual collaboration that made use of visits to the ravaged, debris-strewn site after the blast, analyses by experts and a study of a hand-held gas meter that was recovered from the site and taken apart by the National Transportation Safety Board in Washington, D.C.

Norris, Reardon and their experts, including forensic scientist Henry Lee, also studied evidence stored by Middletown police at a warehouse, including a large defroster on wheels used to thaw construction sites, one of several pieces of equipment left running during the gas blow.

Reardon said he noticed each time he visited the blast site that the companies all had their own experts. The lawyers expect the cases to take years to resolve.

Bartolini said he expects to see the companies point fingers at one another as the cases progress.

Reardon said that the site was "deplorable'' for its lack of safety precautions and that workers who shouldn't have been anywhere near the plant during the inherently dangerous gas blow were directed to continue welding, insulating and doing other tasks — all in a push by the general contractor to get the plant done early and reap millions of dollars in bonuses.

Regulators had expected the plant to open in November, but crews were working 12 hours a day, seven days a week, and the plant was on pace to open as early as May before it blew up.

"That's why they were working on Super Bowl Sunday,'' Reardon said.

Pavano said Hawley told him that the bosses seemed rushed and that there was a sense that they wanted to finish early that day and watch the football game.

Bartolini said there was no reason to use natural gas to clean the pipes, except that the gas was on site and cheap to use.

Norris said the amount of gas forced through the pipes, the location of the vent pipe and the lack of safety controls created a lethal combination. He, Bartolini and Pavano said using compressed air or nitrogen to clean the pipes is far safer.

Reardon noted that two federal agencies — the U.S. Chemical Safety Board and the U.S. Occupational Health and Safety Administration — have noted significant deviations from safety standards and dozens of violations at the plant.

In a separate federal lawsuit filed last month, New Jersey resident Nicholas Novik, a worker who suffered head injuries in the blast, is seeking $6 million against the same three companies.

Like a number of workers at the site that day, Novik's tasks at the plant had nothing to do with the "gas blow" procedure. His lawsuit, filed in mid-August, contends that only a handful of workers, if any, should have been inside the sprawling plant while natural gas coursed through hundreds of pipes.

On Aug. 5, OSHA said the three companies created "deadly conditions" and committed "willful, serious" safety violations before and during the gas blow. OSHA has proposed fines totaling $16.6 million, among the highest ever assessed by the agency.

The Courant has reported that O&G stood to gain a $19 million financial incentive from the majority owners, Energy Investor Funds of Boston, if the plant opened early.

O&G has said that it will appeal the proposed fines, and that it had an exemplary safety record before the blast.