If you do business with Steuerungstechnik und Messgeraete, you could be in big trouble.

The U.S. Department of Commerce has placed the Vienna-based company on its list of "denial parties," revoking its export privileges for trade with the United States until the year 2002.Hundreds of such companies and individuals have been proscribed by the U.S. government as the result of administrative proceedings. This presents a potential legal pitfall for unwary exporters who sell overseas without checking the denials list.

Exporters are responsible for checking before they make a sale. Otherwise, they risk winding up on the denials list themselves, say officials in the Commerce Department's Bureau of Export Administration in Washington.

In practice, officials and trade lawyers say, exporters don't face the full brunt of the law unless evidence indicates the violation was intentional. But they warn that careless dealings can expose exporters to severe scrutiny.

A case in point involves a large U.S. computer manufacturer that was forced to shut down a foreign operation temporarily and pay a hefty fine.

The offense was selling to a denial party suspected of diverting goods to the Soviet Union six years ago.

"Is it a burden on the exporter? I guess it is, but it's very important to keep track of," said one trade lawyer and former enforcement official. ''If you deal with a denial party even by accident, you automatically become tainted."

Often, denial parties are suspected of diverting U.S. goods to Cuba, Libya or other countries subject to trade sanctions, foreign policy embargoes or national security restrictions.

Penalties can be stiff.

Willful violations of denial orders are subject to fines of up to $1 million or five times the value of the exports for companies, and as much as $250,000 or 10 years in jail for individuals. Inadvertent violations may be punished by lesser civil penalties or loss of export privileges, according to the Export Administration Act.

"It's up to you to know that there are certain people you're not supposed to export to, and it's your responsibility to find out," said Robert W. Chmielinski, a Boston trade lawyer.

The problem for many exporters is keeping track of the denials that are published daily in the Federal Register. Most don't have the time or resources to wade through the daily updates of all the federal regulations and decisions, but that doesn't lessen their responsibility to check.

"If you don't do it, it's almost like buying a used car on the street and hoping it's not stolen," said Joseph V. Leone, special agent in charge of the Office of Export Enforcement in Boston.

The easiest alternative is to subscribe to a periodic publication of Export Administration regulations and bulletins. The compilation is available

from the Government Printing Office for $87 a year or $108.75 overseas.

Some electronic services also offer denials updates on line, said John Thomas, a spokesman for the Bureau of Export Administration in Washington.

But experts say vigilance is the best protection against denial parties, who may pull up stakes or simply change their names once they appear on lists.

Mr. Chmielinski recommends that exporters "build" a check for denial status into existing credit-check mechanisms to be on the safe side.

Enforcement officials say there are also many telltale signs that should arouse suspicion in any sale, whether foreign or domestic.

"If they don't ask for warranty on a product, you know there's a problem," Mr. Leone said.

Sellers should also be alert to indications that a supposed domestic sale of equipment might be fake.

Skepticism is advised if the buyer doesn't care about having the equipment set up at the supposed U.S. destination. A U.S. buyer asking for power conversion to a non-U.S. standard also should stir doubts, Mr. Leone said.

The Bureau of Export Administration also advises caution if the requested product does not fit the buyer's line of business or if the product seems incompatible with the technical level of the receiving country.

Other suspicious signs are listing of a freight forwarder as final destination, willingness to pay cash for an expensive item when financing is available, lack of business background or knowledge of product performance Characteristics, vague delivery dates, out-of-the-way destinations or abnormal shipping routes.

The Office of Export Enforcement urges that suspicious orders be reported to its Washington headquarters or any of its field offices.