Hutchinson ? An underground natural gas storage field had been leaking since 1993 and led to the explosions last year when gas burst to the surface through old brine wells at Hutchinson, according to a report commissioned for use in a civil lawsuit.

Operators of ONEOK Inc.’s Yaggy field seven miles northwest of Hutchinson chose profits over safety, employing “reckless pressure gradients” as they operated the field, said M.R. Tek, a Hawaii-based petroleum engineer and professor emeritus for the University of Michigan.

His report was commissioned by the Wichita law firm Foulston & Siefkin, which represents the four adult children of John and Mary Hahn of Hutchinson. The children have sued Tulsa-based ONEOK, claiming gas leaking from the underground storage field sparked the January 2001 explosion that killed their parents. Also named in the lawsuit are two companies ONEOK owns Kansas Gas Service and Mid-Continent Market Center.

ONEOK officials said they would have no response to the report until Monday.

Besides linking the leak at the Yaggy field’s S-1 cavern directly to the explosions, the report also projects upward ONEOK’s estimate of the gas lost from the field from 143 million cubic feet to more than 200 million cubic feet.

Tek said evidence pointed to a “catastrophic leak” from the S-1 cavern as the cause of the explosion.

Before the explosions began, Tek said engineers had noticed pressure problems in the pod that included the cavern that the gas was thought to have leaked from. The pressure, he said, was substantially lower after an extended injection of natural gas that elevated pressure in the pod above recommended limits.

“It appears that the continued injection beyond the pressure limits of Pod 1 finally broke the dam of previously leaked and collected gas along the pathways established earlier,” Tek said.

“All along the path from Yaggy to the town of Hutchinson and even farther east, the escaped gas accumulated and, being pressured, broke through the top soil following old brine wells, eventually igniting and exploding in a trailer park in east Hutchinson, causing the loss of two lives,” the report said.