The U.S. Civil Service Commission has reversed a D.C. police trial board verdict and recommended that an officer who fired on alcohol-related charges be reinstated.

The decision, made by the Federal Employe Appeals Authority of the commission, said that under the law prior alcoholism or alcohol-abuse may not be the sole reason for a federal employes's dismissal.

If upheld, the decision could change the way the District Police Department deals with officers who have drinking problems, according to the attorney who brought the complaint before the commission, James W. Pressler Jr., assistant general for the International Brotherhood of Police Officers.

"What I think this means," said Pressler, "is that before the police department can prosecute a man for being an alcoholic or for having a drinking problem they must make some attempt to assist in rehabilitation."

The officer, Dennis W. Mendell, an admitted alcoholic, was removed from the police force on July 9, 1977, eight months after he pleaded guilty to two charges before the police trial board, according to the documents presented to the commission. Mendell admitted that he had been drunk on duty in January 1976, when he accidentally shot himself in the leg and that he had been drinking while on duty on another occasion in May of the same year.

The commission papers say, however, that Mendell remained on active duty after the incidents for which he was charged until a trial board hearing was held Oct. 1, 1976. The papers also stated that during the five months before the hearing, Mendell's supervisor Lt. Henry Trevethan testified that Mendell had "made a conscientious effort to rehabilitate himself by attending an anti-abuse program five nights a week and by attending counseling sessions with a psychiatrist at the Police and Fire Clinic.

"Lt. Trevethan also testified that (Mendell) was once of his best and most dependable officers and that based on his observations and his performance, the appellant had been completely rehabilitated.

The District government had maintained during the case that police officers are in a "critical-sensitive" position, and therefore are exempt from the federal law giving protection to employes with drinking problems.

The commission ruling said, however, that although employes of the CIA, FBI and the National Security Agency are excluded from the protection, District police officers were not.

George R. Harrod, director of personnel for the District government, said he had not yet seen a copy of the decision but that his "instinctive" reaction would be to appeal the decision to the commission's Appeals Review Board. "Based on the fact that the trial board and the mayor concurred in this decision (to fire Mendell) I doubt that we would overrule ourselves without an appeal," Harrod said. The D.C. government has 30 days in which to appeal.

Harrod disagreed with the commission's interpretation of a critical-sensitive position. "If it were a member of the rank-and-file I would feel different," he said. "But persons like police officers and firemen are uniquely different. One of their basic duties is to arrest people guilty of the same things they are guilty of."

Pressler said that he had "interviewed more than 50 police officers in the last year who have serious drinking problems. The police department seems to think it can handle the problem by firing people or fining them. That's just not true. You fire 150 men tomorrow and it wouldn't solve the problem.

"The only way they're going to deal with this is if they're forced to. This decision could do that. What's more, if a policeman knows he's going to get help and not be fired, he's a lot more likely to come forward and admit he has a problem," Pressler said.

The Civil Service Commission has previously told the police department that it is expected to offer rehabilitation to officers with drinking problems, according to Richard Brooks, general counsel for the police department. This is the first case, however, in which the commission has recommended that an officer be reinstated because the department failed to help him.

The police department recently launched an Employes Assistance Program, designed to counsel officers with personal problems. Former Police Chief Maurice J. Cullinane, who sponsored the program, said that he expected more than 60 per cent of those treated would have drinking-related problems.

The program is designed, however, to help policemen before they become involved in an incident which normally calls for disciplinary action.

Mendell, who said he has not had a drink in almost two years, said that after the police department had discovered his drinking in the shooting incident, "they put me back on the street as soon as I was better. I was bad as ever then.

"Later, when I realized I needed help I enrolled myself in an anti-abuse program. Blue Crosss paid part of the bill, and I paid the rest."