Surgeon General C. Everett Koop, calling smoking the nation's No. 1 health problem, yesterday supported legislation restricting smoking to designated areas in federal buildings.

Koop said nonsmokers constitute more than two-thirds of the adult population and expressed concern that they face health risks as a result of exposure to tobacco smoke.

William E. Alli, representing Local 1534 of the American Federation of Government Employes, told the House Energy and Commerce subcommittee on health and the environment that nonsmokers need protection and that 90 percent of federal employes favor some form of control over workplace smoking.

However, John Mulholland, national president of the union, told the subcommittee that his union would support the legislation if it is established through full collective bargaining. He added that the union considers smoking problem as as air-quality question.

The president of ACVA Atlantic Inc., Gray Robertson, whose company markets devices to reduce indoor air pollution, testified that environmental tobacco smoke would not cause discomfort if ventilation is improved.

Nancy J. Balter, an associate professor of biology at Georgetown University, who acknowledged that she is a paid consultant to the Tobacco Institute, the tobacco trade association, argued that a " . . . cause-effect relationship between environmental tobacco smoke and lung cancer in nonsmokers has not been established."

Robert D. Tollison, professor of economics at George Mason University, who is also on the payroll of Tobacco Institute, told the panel that the legislation has a high price. He said that the cost of restricting smoking in all U.S. government buildings would exceed $761 million. He said federal worker productivity would decrease if they could not smoke at their worksites and that smoking breaks would result in lost work time.

Marvin Kristein, professor of economics at the State University of New York (Stony Brook), said it was "fantasy" to claim that the legislation would cost the government millions of dollars. "More likely is that workplace smoking policies actually help to increase productivity by reducing the discomfort and irritation to nonsmokers," he said. He also criticized the tobacco industry for treating smoking as a freely chosen consumer activity enjoyed by many people, "like chewing gum or eating candy bars."

"I urge the committee to take this important step to protect the health and comfort of federal workers and visitors to federal buildings," Kristein said.

Dr. Alfred Munzer, an official of the American Lung Association who testified on behalf of the Coalition on Smoking or Health said his patients were suffering from symptoms as a result of exposure to tobacco smoke. "Preliminary reports indicate that involuntary smoking increases the risk of death from heart disease," he said.

At the end of the three-hour hearing, J. Thomas Burch, chairman of the National Vietnam Veterans Coalition, expressed concern over the legislation. He reported that 75 percent of Vietnam veterans were smokers. "Many of them developed the taste for tobacco during service to their country under highly stressful wartime situations," he said, adding that the legislation could further contribute to the alienation of these veterans.