WASHINGTON (AP) _ The Equal Employment Opportunity Commission said Friday that it mistakenly turned over to a broadcast executives' newsletter a list of 100 people who had filed discrimination cases against radio stations.

The list was published by Inside Radio last Jan. 21, prompting a protest by a black Pittsburgh television reporter who charges that divulging the names amounts to an industry-wide ''blacklist.''

The EEOC is investigating the circumstances that caused a list of employees, their radio station and the nature of their complaints to be given to the trade journal, which is based in Cherry Hill, N.J.

''It happened, God knows how it happened,'' said EEOC spokeswoman Deborah Graham. ''It's my understanding that our audit office is trying to figure out who is responsible and make a recommendation to the office of the legal counsel on what should happen.''

Another EEOC spokesman, Reggie Welch, called the matter ''an unfortunate mishap,'' saying, ''The administrative process is not supposed to be a matter of public record.''

The list was published in the newsletter as part of a two-part series on discrimination suits against radio stations, said the journal's publisher, Jerry DelColliano.

The series contained advice on how stations could avoid such cases. ''This purpose of this listing is to dramatize how widespread the threat is becoming,'' the feature said. ''To warn stations to take protective measures to prevent a suit of this type from occurring.''

Included on the list of complainants, whose first initials and last names were published, were cases involving alleged discrimination because of race, sex or pregnancy. The complainants alleged injustice over hiring, wages and promotions, among other issues. Most of the cases were filed in 1984.

''Many of these people are probably out there without jobs and they don't know they have been blacklisted,'' said Greg McCampbell, a black reporter with WTAE-TV of Pittsburgh.

Even though he is a television reporter, McCampbell's name appears on the list. He said he has filed a discrimination complaint against his station, but would not discuss it on the advice of his attorney.

''I'm going on the record because my career is at stake,'' he said. ''The EEOC - the very people who are supposed to protect my rights - are violating my rights.''

DelColliano said his newsletter paid the EEOC between $100 and $150 for the list - the cost, he said, of the computer time required to find the information. At the time, the EEOC ''saw nothing wrong with giving it out,'' he said.

''The public has a right to know this stuff,'' he said. ''We were very careful to stick to the facts.''