In Takoma Park, a two-martini lunch or even a noontime glass of wine may soon be risky choices for the 150 people who work for the city government.

Concerned that job performance may be impaired by drug or alcohol use, the City Council is considering banning alcohol consumption at any time during the workday, including those occasions when workers leave city property on their lunch breaks.

While the proposal, which is believed to be the first of its kind in the Washington area, would prohibit city employees from drinking any alcoholic beverage during work hours, violations would not constitute automatic firing offenses, officials said.

Instead, supervisors would be responsible for assessing whether the use of alcohol or illegal drugs hampers the abilities of their workers, much as they are now.

"It's really about job impairment and not about moralism," said City Council member Hank Prensky.

The notion of regulating lunch-hour behavior has brought little resistance from the unions representing city workers. But Gino Renne, vice president of Local 400 of the United Food & Commercial Workers Union, which represents Takoma Park police officers as well as Montgomery County government workers, said he would object to a blanket prohibition.

Renne noted that Takoma Park police officers are already prohibited from drinking during their shifts, but said most other workers should not be subjected to an "absolute prohibition" against alcohol consumption.

Mayor Edward F. Sharp said a total ban was the fairest proposal. Otherwise, said Sharp, "Where do you draw the line?"

Jim Douglas, a member of the City Council, which will vote on the proposal this month, said that while the government was not embarking on a "witch hunt," government employees should consider themselves on the job "even when they're at lunch."

Arthur Spitzer, legal director of the regional American Civil Liberties Union, said employers had the right to worry about their employees' alcohol use, within certain limits. "An employer does not own your soul," Spitzer said.

Tallie Summerlin, the owner of Taliano's, the city's only restaurant serving alcoholic beverages, said his patrons rarely have more than one or two drinks at lunch.

"I just don't think this is necessary," Summerlin said of the proposed regulation. "It's not like people are leaving here drunk."

Even if the City Council imposes a drinking ban on government workers, Sharp, a part-time mayor, said there still could be instances when elected officials might imbibe during the work day: at receptions related to city business.