The war over tobacco smoking is shifting away from restaurants and airplanes to corporate personnel offices, as state after state takes up the vexing question of whether employers may refuse to hire smokers.

Behind the trend is the relentless rise in the cost of medical care, which has left employers scrambling to rein in runaway insurance premiums. At the same time, public intolerance of smoking appears to have reached a record high.

OPPONENTS: On either side of the scrimmage are seemingly unlikely allies: The tobacco industry and the American Civil Liberties Union have joined forces, often with organized labor, while anti-smoking activists have teamed up with chambers of commerce.

So far, perhaps 23 states have adopted some form of law protecting smokers against discrimination in hiring, terms of employment and firing. The laws do not defend smoking in the workplace; they simply seek to protect what employees do on their own time.

In just as many other states, similar bills have been blocked. In California, one of the first states to consider the issue, Gov. George Deukmejian vetoed a smokers' rights bill in 1989. He called the legislation unnecessary, saying at least one court had ruled that smokers can sue for wrongful discharge.

New "smokers' rights" bills are pending in many states.

"We don't think your employer owns you," said Lewis Maltby of the ACLU. " . . . Your employer has a right to expect you to do your job well and respect the rules, but they don't have a right to run your private life."

William M. Shaw of Turner Broadcasting System Inc. countered: "We as a company should have the right to select who we hire, and they have the right to accept the job or not. We're not trying to impose anything on anyone. We just have conditions of employment."

BACKGROUND: It is not known how many U.S. companies refuse to hire smokers. Turner Broadcasting, with 5,000 employees, is one. Under a policy approved by employees in 1986, Turner requires all new hires to sign a no-smoking agreement.

New employees who smoke are given 30 days to quit and are offered free smoking-cessation classes on company time. Smokers hired before the policy began may continue to smoke in designated areas at work. The aim is a healthy work force, not lower costs, Turner spokesmen say.