Paul Mann, who is black, says he was warned he was walking into a "hornet's nest" of prejudice when he was hired as a shop foreman by Browning Ferris Industries Inc., a national trash and chemical waste disposal firm with operations in Fairfax County.

Three weeks later, Mann was fired. The reason given, he says: his inability to get along with seven white mechanics he supervised.

Last week Mann, 41, who says he also was told by the man who hired him that many of his subordinates were "dyed-in-the-wool rednecks who did not like blacks," filed suit in federal court in Alexandria, claiming race as the sole reason for his July 1979 dismissal.

In his suit, Mann, a Woodbridge resident, also contends he was denied a promotion to maintenance manager despite a degree in industrial engineering and 23 years of managerial and technical experience gained while serving in the Army.

The man eventually hired for the position, who was white, had far less experience, according to court papers filed in the case.

"It's an egregious and blatant example of race discrimination," says Patricia Horton, head of the Fairfax Human Rights Commission, which investigated Mann's charges in August and said it found "reasonable grounds" to support him.

"Rarely do we see a case like this where there really appears to be very little evidence supporting the company's position," Horton said.

John Harper, an attorney at the firm's Houston headquarters, says it isn't so. "Mr. Mann is trying to push his shortcomings off on others," Harper maintains. "He was unable to organize and get the work out in the technical manner necessary."

Harper adds that other Browning Ferris supervisors warned the mechanics at the company's Merrifield shop they should quit if working for a black man posed a problem.

But according to Mann, intense racial hostility at the shop -- where blacks were employed only in the lower-paid position of garbage truck driver -- made it almost impossible for him to perform his job during his brief, three-week stint. Many of the white mechanics refused to follow directions, sabotaged Mann's work and harassed him, he says.

When he complained about the alleged harassment, he says, nothing changed -- except that he was fired.

"I wasn't shocked that it [harassment] occurred," Mann said in an interview last week. "I'm an adult and I know these things exist. But I was surprised I didn't receive any support from my supervisors. They said they didn't want to see a lot of changes."

Mann contends that when he tried to make changes of his own, suggesting the company hire a black mechanic, a shop supervisor told him, "If you hire a black man, every man will walk out tomorrow."

The supervisor, Sam Ziff, declined to comment on the allegation. Harper, the Browning Ferris lawyer, says the comment was taken out of context. The suggested mechanic was technically unqualified, Harper says, adding that Ziff had said that if the man were hired, the other mechanics would protest on that basis.

The case is expected to be heard within the next two months. Meanwhile, after three months of searching, Mann found another job paying $18,000 a year, $10,000 less than his annual salary at Browning Ferris.

"I won't let this wreck my life, but, sure, it has had a major effect," he says. "You just can't measure what it does to your confidence. You begin to wonder whether you are as good as you thought you were. I know I was good at one time."