Bulk business advertisements, more commonly known as "junk mail," have repeatedly been trashed at Lincolnia Station in Alexandria, according to postal workers.

"They said dump it, and we dumped it," said Larry C. Seeley of Silver Spring, who has charged that supervisors at the post office directed him to trash mail because of personnel shortages and their refusal to pay overtime.

The supervisors, Robert Vincent and Richard Winner, flatly denied Seeley's charges. A postal inspection in June, prompted by Seeley's complaint in April, revealed no wrongdoing.

Five other postal employes, who asked that their names not be used for fear they would be fired, said in interviews that they have seen deliverable third-class mail discarded at the station. "I have seen it happen," said one worker, who claimed the supervisors usually order a temporary employe "to take this bucket and dump it."

"It would take 20 hours a day to sort the bulk mail," he continued. "You just can't do it. And then the next day, it just builds up and builds up and builds up. And then management will come around secretly and decide what to dump."

The worker said he has seen employes trash mail from Caldor, Woodward & Lothrop, Hecht's and Arlington Hospital. Other workers said large bundles of mail -- up to 1,000 pieces at a time -- "disappeared" after they told their supervisors about deliveries that should have been made.

Vincent said he had no comment on charges from those employes. "There's absolutely no way that happens," said Winner.

Postal Service spokesman Bob Hoobing said incidents of mail being dumped are "extremely rare." A postal worker can be jailed or fined under federal codes for such actions, he said.

National direct-mail officials said the problem occurs more often than postal officials acknowledge. "It's a problem we've been trying to get the Postal Service to attend to for some time," said Gene A. Del Polito, executive director of the Third Class Mail Association.

A 1983 study by Doubleday Inc. and the Direct Marketing Association said that nondeliveries of bulk mailings varied from 3 percent to 19 percent.

The Postal Service and Direct Marketing Association are conducting tests to determine the extent of the problem.

More than 52 billion third-class pieces were mailed in 1985, earning the Postal Service revenue of $4.8 billion, up significantly from 1981 figures of 33.6 billion pieces earning $2.6 billion. Of the 140 billion pieces of mail for 1985, 37 percent were sent third class.

Louis Delgado, staff director of the House subcommittee on postal operations, said his office receives complaints about undelivered mail "from every part of the country."

Delgado received one of Seeley's letters to Rep. Mickey Leland (D-Tex.) and forwarded it to Postmaster General Albert V. Casey, who subsequently requested the June field investigation. "It was obvious that he Seeley had really done his homework," Delgado said. "It seemed very thoughtful. It didn't seem off the wall in any way. That's why I pursued it."

Delgado hadn't heard what happened as a result of the investigation, and said the committee will ask Casey for the results of the probe. "I'd like to know what kind of investigation it was," Delgado said.

According to Gerald F. Merna, manager of the Merrifield Sectional Center, officials from the Alexandria Post Office interviewed the managers at Lincolnia Station and received written statements denying the charges.

The report carried no reference to the investigators having interviewed letter carriers.

Officials also made three surprise checks of the facilities, checking garbage cans and the dumpster in the back. Investigators found no deliverable mail, Merna said.

According to Seeley, 39, postal carriers and supervisors regularly dumped mail. In his April 29 letter to postal inspector Thomas Ryan, Seeley recalled three instances during his seven-month stint when mail was dumped.

"Things like this happen almost on a routine basis," said Seeley, who transferred to the main Hyattsville Post Office after seven months, so he could be closer to home. He then quit his Maryland job after a month because of what he termed "mismanagement and disagreeable working conditions."

He has since filed a complaint with the Wages and Hour Division of the Department of Labor. Seeley also has spoken to aides for Rep. Steny H. Hoyer (D-Md.). "We are looking into some of the things he is saying," legislative assistant Cynthia Bradley said.

The supervisors, Winner and Vincent, denied that the incidents took place. "I think they're completely absurd," said Winner.

Seeley passed his 90-day probationary period, during which his contract could have been terminated if he hadn't met postal standards.

One Lincolnia Station carrier, union representative Dan Doherty of Chantilly, agreed with Seeley's statement that most carriers are overworked. "The majority of the routes are overburdened," he said, citing an increased volume of mail that often requires costly overtime assistance. "This could lend itself to a situation where management would authorize throwing away bulk business mail deemed to be excess or duplicative.

"You're supposed to try to deliver all of that," he said.

Barbara Sly, direct-mail targeting manager of Hecht's, said she was surprised and skeptical of the charges. "The fact that I'm hearing about late mail doesn't mean that mail isn't being trashed," she said. "I don't know."

Other area bulk business mailers said they knew nothing of the allegations. "I certainly wouldn't have a hint that it was being destroyed," said Lee Owings, of Harte-Hanks, a direct-mailing company in Baltimore.

Lee Epstein, president of Mailmen Inc., a New York letter-mailing company, said it is difficult to know exactly how much mail might be destroyed.

"We find these things exposed or caught in different parts of the country at different times, which would indicate that it is happening at various times or places, so it is not an isolated instance," he said. "What is isolated is the catching of these people."

Added Delgado, "I don't think it's systematic or anything, or it might not be intentional, but clearly there are times when big shipments disappear."

He said, "What happens to them? Are we charging people for a service we can't provide for them?"