Last July, a major drug manufacturing company discovered that a list of confidential, inactive ingredients in a new drug it was about to market had been made public by the Food and Drug Administration.

FDA released the trade secrets, including a diagram of the drug's molecular structure, by accident when it responded to a Freedom of Information Act request filed by one of the drug-maker's competitors.

Such snafus have come under increased scrutiny in Congress since 1980, in part because business groups feel the climate for changing the FOIA is much more favorable now than when the act was passed in 1966 or during the Watergate era when its powers were broadened.

FDA is getting a big share of that attention for three reasons: It receives more FOIA requests than any other federal agency (34,000 requests in 1982), an estimated 86 percent of those come from companies who want to know what their competitors are up to, and, according to Congress, FDA has released confidential information by mistake more times than any other agency.

After the July mishap, Harry M. Meyer Jr., director of the FDA's National Center for Drugs and Biologics, issued a stern internal memo warning employes to be careful when answering FOIA requests. FDA also apologized to the company and promised to retrieve the confidential documents.

That was not enough, however, for Congress. In October, two congressional panels demanded that FDA begin notifying companies in advance before it released any business information that might be considered sensitive. Such a pre-notification policy would give a business a chance to argue against disclosing documents and go to court, if necessary, to stop FDA from releasing them.

FDA is the only major federal agency that doesn't have a pre-notification policy, and the congressional panels warned the agency that if it doesn't voluntarily adopt one, Congress might force it to.

"Like it or not, it is apparent that the FDA will eventually be required to provide greater protections to submitters," Rep. Glenn English (D-Okla.) told FDA Commissioner Arthur Hull Hayes Jr. in an October letter. "There is no reason for FDA to wait."

FDA agreed to study whether a pre-notification policy was necessary. It began reviewing 700 FOIA cases filed during 1982 to determine how many would have required companies to be notified in advance and, if so, how expensive it would have been. The study is scheduled to be complete in February.

Gerald Deighton, director of the agency's FOIA program, said FDA has resisted pre-notification because it feels its employes are competent to decide what they should and shouldn't release. If companies had advance word of an FOIA request, Deighton contended, they would try to keep everything secret and the process would get bogged down. The current law contains enough safeguards to protect secrets, he said, and when FDA's output is considered, the number of mistakes is small.

James T. O'Reilly, senior counsel to Procter & Gramble Co. and author of several books about FOIA, counters that companies wouldn't waste money blocking the release of documents if they weren't worth protecting.

In 1980, FDA inadvertently released one of Procter & Gramble's trade secrets, he said. If the company had been warned, the mishap could have been avoided.

"They always apologize but that doesn't help," said O'Reilly. "I don't think the government pays people adequately or trains people adequately to form the kinds of competitive judgments that have to be made. The FDA is buying a lot of trouble by not notifying businesses in advance."

O'Reilly and scores of other attorneys and businessmen told House and Senate hearings in 1981 that agencies had released confidential business data, often by mistake.

Since 1981, Senate and House subcommittees have reviewed legislation that would have made the FOIA more palatable to the business community. Officials at both panels expect similar legislation to be introduced this session--only this time FDA's foul-up will be at the top of the business community's list of horror stories.