The glowing screens of video display terminals (VDTs) have replaced typewriters in many offices, and now efforts to regulate their use because of health concerns may become just as commonplace. About 25 states are expected to consider VDT bills this year, touching off major political fights.

Some recent studies have linked VDTs with headaches, vision problems, and muscular and skeletal disorders, all from the strain of being tethered to a screen for long periods of time. Critics also charge that the terminals may have a role in causing cataracts, birth defects, and reproductive problems. About 12 million people work on VDTs, but there are no federal regulations to govern their use.

The bills would require employers to supply movable screens and detachable keyboards, adjustable chairs and tables, and glare- and noise-reducing devices. Some of the proposed legislation would require companies to reassign pregnant workers and pay for eye examinations and eyeglasses. The typical fine for violations: $1,000 a day.

"If these standards are mandated, many small businesspeople will be forced out of business," says Mark Davidson, state director for the Ohio chapter of the National Federation of Independent Business. For example, some companies might be unable to supply alternative work for pregnant employees. "If you've got a small company with five employees and two can't work on VDTs, the law would say you still have to employ them," says Vico Henriques, president of the Computer and Business Equipment Manufacturers Association.

But supporters of the bill say that protecting employee health should be an overriding concern. "Providing free eye exams could be expensive, but people who work with headaches are often less productive," says Elaine Taber, program director of 9 to 5, The National Association of Working Women."It is irresponsible to expose people to these dangers."