Federal investigators seized a file containing the names of Pentagon employees with "homosexual proclivities" when they arrested a Navy enlisted man on espionage charges last week, according to sources close to the investigation.

Military investigators are checking the names to determine whether there has been any breach of Pentagon security by homosexuals who might be susceptible to blackmail threats, the sources said.

Lee Eugene Madsen, 24, a security officer for a sensitive Pentagon office run by a CIA official, was charged last Tuesday, a few days after he allegedly stuffed a "top secret" document down his pants, walked past Pentagon security guards and handed the document to an undercover FBI agent.

Sources said Madsen is a homosexual, a disclosure that concerned Pentagon officials because Defense Department policy is to discharge known homosexuals from the military services.

It could not be learned how many names were in the files in Madsen's possession or whether any of the individuals were in jobs as sensitive as his.

A Pentagon spokesman declined to comment on the Madsen case, but said it is still policy to discharge homosexual members of the military because their "presence in a military unit would seriously impair discipline, good order, morale and security."

Justice Department officials emphasized in arresting Madsen last week that they had no evidence he passed any classified documents to a foreign power.

But intelligence officials privately expressed special concern when they learned Madsen was a homosexual because of his access to highly classified material, including supersensitive information obtained by intercepting foreign government communications.

The CIA, FBI and other intelligence agencies traditionally have disqualified homosexuals as job applicants or dismissed them when discovered because of the possibility a foreign agent could blackmail them into giving up national secrets.

Madsen, a yeoman third class, is accused of taking $700 from FBI undercover agent William Chapin and from another man, Richard Grant Noble, who first alerted authorities Madsen was willing to steal documents.

Documents filed in the case allege that Madsen took Chapin on a late-night tour of his Pentagon office Aug. 10, casually signing him past two guards by using a phony name.

Madsen then allegedly showed Chapin a "top secret" report entitled "USSR/Warsaw Pact General Indicator List," stuffed it down his pants and carried it past the guards.