CHICAGO (AP) _ Maude DeVictor was a low-level Veterans' Administration bureaucrat eight years ago when she first heard the words ''Agent Orange.''

''I knew something was there but I didn't know how much,'' she recalled in a recent interview, ''like when you see lipstick on your husband's shirt.''

Since that warm June day in 1977 when the sobbing wife of a U.S. serviceman telephoned to say the ''chemicals in Vietnam'' had caused her husband's cancer, Ms. DeVictor has been on a crusade to make someone accountable.

She began with the VA, forcing the agency to pay unprecedented survivor benefits to the serviceman's wife, but didn't stop there. She became an expert on Agent Orange, a pariah to the VA, and a hero to the Vietnam veterans whose cause she helped shape and champion.

Now, with those veterans on the verge of sharing a $180 million settlement from the makers of Agent Orange, Ms. DeVictor has become something of a martyr as well - broke, jobless and drifting toward bitterness.

''I knew even before I got deep into this,'' she said, working through one cigarette after another, ''that there aren't any support groups for 'enemies' of the country.''

She hasn't worked since the VA fired her in November 1983 after nine years of service, claiming she spent too much time on union business and citing her for ''conduct unbecoming a federal employee.''

Ms. DeVictor, 44, a short, roundish woman with a quick smile and close- cropped Afro, is fighting to get her job back, contending she lost it for being a ''whistle-blower.'' The VA denies that Agent Orange had anything to do with her dismissal.

Her crusade has won Ms. DeVictor a place in the hearts of Vietnam veterans, who hold fund-raisers to provide her with meager living expenses. An independent producer is preparing a made-for-television movie about her crusade titled ''Unnatural Causes.''

''She is the mother, so to speak, of Agent Orange,'' said Victor Yannacone, the Long Island, N.Y., attorney who filed the original lawsuit against manufacturers of the herbicide.

''She was the one who made the connection, one of the first to rally the vets,'' he continued, ''the one who helped restore their dignity and show the illnesses weren't just in their heads.''

U.S. District Judge Jack B. Weinstein of Brooklyn, N.Y., who presided over the settlement and repeatedly expressed sympathy for the veterans, nonetheless said the plaintiffs had shown ''no factual connection'' between their diseases and Agent Orange.

As part of the settlement, the seven chemical companies did not admit any liability. But the veterans harbor no doubts.

''They keep telling us there's no answers yet on Agent Orange, but it's too late for a lot of people already,'' said Chris Molloy, a veteran who befriended Ms. DeVictor several years ago. ''And if we let the system treat a conscientious employee like Maude this way, it's going to be a signal that it's OK to do it to everybody else.''

During closed hearings before a federal arbitrator, VA attorneys documented that Ms. DeVictor, who became chapter vice president of the American Federation of Government Employees, spent more and more job time on union business.

Because her case is in arbitration, ''we are prevented from telling our side by the Federal Privacy Act,'' said Grady Horton, director of the agency's Chicago region.''But I can categorically deny that it had anything whatsoever to do with Agent Orange.''

Ms. DeVictor was a college-educated single mother trying to rear a 13-year- old son in a South Side housing project when she encountered the issue. On June 11, 1977, she picked up the phone at the Lakeside VA Hospital and answered the ''call that would change my life.''

Ethel Owens sobbed as she told Ms. DeVictor that her husband, Charles, was dying of cancer four years after completing a 24-year Air Force career.

Twelve days later, Mrs. Owens called back and asked to file a claim listing her husband's death as service-connected, which would have entitled her to an additional $260 a month in survivor benefits.

Such claims are allowed only when the vet contracts the illness during his military service, Ms. DeVictor said. ''But two things from our phone conversation kept running through my mind.

''Charles told his wife if he died of cancer, it would be the 'chemicals in Vietnam' that finished him. She also remembered as they were flying into Los Angeles once, he said the smog reminded him of the 'spraying we did in Vietnam ... how sometimes it got so thick you couldn't see your hand in front of your face.'''

After the claim was denied by the Chicago regional VA office, Ms. DeVictor began working on an appeal.

From Capt. Alvin Young of the Air Force surgeon general's office, she first heard the name ''Agent Orange'' and learned of its deadly by-product, dioxin.

Ms. DeVictor devoured the literature on past incidents of chemical contamination and began asking every Vietnam vet who called the VA whether their children had birth defects, if their wives had miscarried, or if they had skin rashes, unexplained bouts of depression or loss of sexual appetite.

She called Dow Chemical, the World Health Organization, the Occupational Health and Safety Administration, professors, doctors and even the CIA to learn ''if they had any problems with their operatives in Southeast Asia.''

Ms. DeVictor made 384 telephone calls, and presented Mrs. Owens' appeal in May 1978 to the VA office in Washington.

''By simply doing my job, I did for less than $200 what a blue-ribbon panel would charge taxpayers millions to do,'' she said.

She also sent her files to the media and found a sympathetic reader in Bill Kurtis, then the anchorman for Chicago's CBS affiliate, who developed a documentary, ''Agent Orange: The Deadly Fog.''

The day after the documentary aired, Ms. DeVictor said, VA headquarters in Washington ordered officials in Chicago to limit reporters' access to her.

''They were telling me to stop, but I did not stop. There was no way I could,'' she said. ''You can't just get paid, go home and stare at the four walls.''

Friends on the VA switchboard managed to route some of the ever-increasing calls to Ms. DeVictor, and when she went home, it wasn't unusual to spend the evening making and taking long-distance calls from vets.

The crusade filled a vacuum in her life. Her marriage had lasted just long enough to produce a son; another relationship was broken off, she believes, because cancer had taken one breast.

At about the same time, a tireless Vietnam vet from Connecticut named Paul Reutershan was wasting away from cancer, and swearing that before it consumed him, everyone would know about Agent Orange.

''I died in Vietnam, but I didn't even know it,'' Reutershan said with typical dramatic flair on NBC's ''Today'' show in 1978.

In May of that year, he founded Agent Orange Victims International, and in July 1978, convinced ABC's ''20/20'' to do a segment on Agent Orange. Ms. DeVictor and Reutershan appeared in separate film clips during the show and they soon became friends.

In the fall of 1978, Mrs. Owens' appeal was approved by the VA in Washington - a cause for only brief celebration.

''They (VA headquarters) took great pains to let us know this was a once- in-a-lifetime case,'' Ms. DeVictor said. ''They apparently began toting up the costs and realized this kind of thing could be financially prohibitive.''

Reutershan died in December 1978, but the momentum they had generated did not slow. On Jan. 8, 1979, Yannacone, who spearheaded the successful 1960s legal battle to take DDT out of the marketplace, filed the lawsuit on behalf of Reutershan and an unnamed class of Vietnam veterans.

''Would I do it over again? In a second,'' Ms. DeVictor concluded. ''I wasn't hired to be the bosses' friend. I was hired to serve this country.''