PORTLAND, MAINE -- On Friday afternoons at J's Oyster bar and restaurant, the beer flows freely, waitresses shuck oysters by the dozen and cigarette smoke hangs in a cloud over the bar.

Beer, oysters and cigarettes are regular staples at J's, a popular waterfront place where fishermen belly up alongside students and business executives.

Cigarettes, however, soon may become history at J's and hundreds of others restaurants, diners, bars and fast-food outlets throughout the state. Officials are now considering a proposal to ban smoking in all one-room establishments that serve food. It would be the most radical such measure in the country.

Proponents of the proposal say a smoking ban is a much-needed step toward a smoke-free environment where nonsmokers won't be subjected to the dangers of other people's fumes.

But restaurant owners say the law would drive customers to larger businesses that have more than one room, where smoking still would be allowed.

Cindy Moran, the president of J's who works the bar during "happy hour" on Fridays, says she might go out of business if the law goes into effect.

"Ninety percent of these customers wouldn't be here if they couldn't smoke," she said.

Joy Fontana, perched on a stool with a lighter saying "Smokers Rights" by her side, said, "I wouldn't go to a bar if I couldn't smoke."

Local, state and federal officials in recent years have passed scores of laws nationwide banning smoking in offices, airplanes, hospitals, elevators, public buildings and other places. But the proposal now under consideration in Maine would become the strictest anti-smoking law in the land if it is passed as now written, according to the Tobacco Institute, a Washington-based lobbying organization for tobacco manufacturers.

Tom Lauria of the institute said Beverly Hills, Calif., passed a law in 1987 outlawing smoking in all restaurants, regardless of size, but it was rescinded four months later after restaurant owners complained they were losing millions of dollars to establishments in Los Angeles where customers could smoke if they wanted.

"The proposal in Maine right now is the strictest in the nation," Lauria said. "There's nothing that comes close."

Nonsmokers and health officials maintain that the proposal is a matter of public health. They say that anywhere the public is invited, people shouldn't be have to breathe other people's smoke.

"We believe that secondhand smoke can cause cancer, irritants and health hazards," said Edward Miller, director of the Maine Lung Association. "We'd like to see smoking banned in any enclosed area."

The state passed a law three years ago requiring that restaurants set aside areas to meet the needs of the nonsmoking public. A survey last year, however, revealed that in one-room establishments, nonsmokers weren't "reasonably" isolated from smoke.

The state Legislature then entered the picture, instructing the state Department of Human Services to write new regulations that would safeguard nonsmokers.

The department's proposal would prohibit smoking altogether in one-room establishments that serve food. It also would require restaurants with more than one room to set aside 70 percent of their seats for nonsmokers and to segregate smokers from nonsmokers with floor-to-ceiling partitions.

More than 1,000 coffee shops, neighborhood pubs, mom-and-pop diners, fast-food restaurants and other businesses would be affected, said Carl Sanford, executive vice president of the 600-member Maine Restaurant Association.

For business owners, the proposed law is a matter of dollars and cents. One-room proprietors say it would drive their regular clientele who like a smoke with their coffee or after-work drink to larger establishments that can conform with the law.

"In this case, people don't realize how many one-room restaurants there are in Maine," Sanford said. "Also, we've had it up to our eyeballs with the government telling us how to run our businesses."

Moran, busy serving thirsty customers at J's, said it is unfair for the state to pick on one particular type of restaurant.

"If they don't want smoking, they should ban it in all restaurants, not in just one kind ... like mine," she said.

Smokers say the law infringes on their rights and that nonsmokers don't have to come into J's or any other bar or restaurant that doesn't segregate smokers from nonsmokers.

State officials have held hearings on the issue and received more than 300 letters expressing opinions for and against the rules. During one hearing, a fight nearly broke out between smokers and nonsmokers outside a hearing room in the state capital of Augusta.

Bob Peterson, manager of the state's lodging and eating program for the Department of Human Services, said department staff members now are writing a final recommendation on what the law should be.

There are several options, including recommending that the proposal becomes law as it now reads or coming up with a compromise, such as one that exempts existing one-room businesses from the regulations. A final decision by the department commissioner is expected later this month or in early July.

In the meantime, the issue will remain a topic of debate.

People such as Bob Ward, a nonsmoker sitting at a table at J's with both nonsmokers and smokers, said he welcomes the chance to come into smoke-free bars.

"I'm all for it," he said. "It ain't going to happen, but I'm all for it. I don't think fairness has anything to do with it. We're talking about quality of health."

And then there are people such as Sanford, who maintain that the law is unfair to small-business owners.

"I hope sanity prevails," he said.