The 1974 death of Oklahoma plutonium worker Karen Silkwood has been called an accident and not murder by attorneys for the House Subcommittee on Energy and Environment.

Committee attorneys also say their investigation has turned up no evidence that a plutonium theft and smuggling ring existed at the Kerr-McGee Corp. Cimarron nuclear plant north of Oklahoma City.

Their findings appeared in a Jan. 12 memorandum mailed by attorneys Michael J. Ward and Paul E. Kritzer to members of the subcommittee.

The six-page memo was written in response to articles in Rolling Stone magazine that suggested that Silkwood was murdered because she had discovered a plutonium theft and smuggling ring at the plant.

The letter has the effect of exonerating Kerr-McGee of any connection with the Silkwood death. But in reporting that "missing" pluntonium eventually turned up at the Cimarron plant, is highly critical of reporting practices required to private industry concerning inventories of nuclear fuel.

The attorneys also criticized the handling of the Silkwood case by the Justice Department, which they claim has failed to submit certain information requested by the subcommittee.

The subcommittee has indefinitely suspended hearings in the Silkwood case because of pending litigation brought by Silkwood's parents against Kerr-McGee, and Ward said today he doubts the subcommittee will ever again hold hearings in the Silkwood case.

Silkwood was killed in a one-car accident near the Cimarron plant on Nov. 13, 1974, several days after she and her apartment had been contaminated by plutonium.

The 28-year-old woman, who apparently fell asleep at the wheel after taking a tranquilizer, had told associates she was on her way to provide a New York Times reporter with documents relating to allegedly lax safety standards at the plant.

"The staff could find no credible evidence to challenge the conclusion that Silkwood died in a one-car accident" the memo states, ruling out the opposing theory that Silkwood may have been deliberately forced off the road by another vehicle.

The memo states that investigators have found no evidence to indicate Silkwood had sensitive documents with her at the time or, if she did, that they had been stolen.

While the missing plutonium at the Cimarron plant was eventually located, attorneys Ward and Kritzer said classified documents from other plants obtained through the General Accounting Office showed "wildly" "yrating" issues for "Material Unaccounted For" (MUF). They called the MUF accounting system "inaccurate, unreliable and unable to provide timely alarm in the event of an actual theft."

Dean McGee, board chairman and chief executive officer of Kerr-McKee, declined to comment on the memo, saying his attorneys had advised him not to make a public statement because of the pending lawsuit.