Subpoenas have been issued to Morton Thiokol, the manufacturer of solid-fuel rockets for the space shuttle, as part of an ongoing federal investigation, an FBI agent confirmed.

"There were subpoenas that were issued (o Morton Thiokol) for certain documents, but I don't know what the results of those are or if they will bear fruit or what," FBI agent Cal Clegg told The Seattle Times.Clegg, contacted by The Associated Press at his Salt Lake office, confirmed Wednesday the subpoenas were issued as part of "an inquiry. Allegations have been made, and we are trying to refute or prove them."

Clegg said the FBI does not yet know if there will be any litigation.

Court documents reveal that an investigation began in January 1987 when Thiokol safety consultant Steve Agee, working undercover for the FBI, told federal authorities he felt safety information about the shuttle rocket was being suppressed.

Thiokol manufactured the booster used on Challenger, which exploded over Cape Canaveral shortly after take-off in January 1986, killing all seven aboard. The work was done in Utah and was according to NASA specifications.

Agee said that while working as a safety analyst at Thiokol, he wrote numerous reports on hazards associated with the shuttle's booster rockets, but that the reports were shelved.

Thiokol officials said the reports were not submitted to the National Aeronautics and Space Administration because they were not credible.

Agee worked at Thiokol as an undercover agent for the FBI from November 1986 to late March 1987 and, at the direction of an official FBI agent, he brought out copies of documents. He also dined with Thiokol employees at an Ogden restaurant and discussed safety practices while wearing a hidden microphone for the federal bureau.

Agee, who now lives in Renton, Wash., said the FBI told him it had obtained court authorization for him to smuggle out documents and record conversations.

After Agee left Thiokol, he became a four-month, full-time consultant for the FBI. He helped the FBI examine Thiokol's contract with NASA to build booster rockets for the space shuttle and track numerous areas of potential criminal conduct, including contract fraud and false statements.

Morton Thiokol general counsel Darryl Lee would neither confirm nor deny whether the company had received a subpoena. "If there is such a subpoena, the company intends to cooperate fully with any investigation," he said.