Occupational health specialists, who traditionally focused on heavy industry, are following the American labor force from the factories and the mines into the office.

And they're discovering a whole new range of worker health issues, from office lighting to indoor air pollution to the design of desks and chairs.

"What happens to people when they're in the office eight hours a day or more has a very important effect on their overall health," says Dr. Peter Gann, an epidemiologist at the National Academy of Sciences and co-medical director of the Alice Hamilton Occupational Health Clinic in Washington.

Nearly 10 million workers spend most of their work day sitting in front of a computer screen and keyboard called a video display terminal or VDT. The proliferation of VDTs -- 40 million workers will use them by 1990, experts estimate -- has revolutionized the nature of work in banks, newsrooms, insurance companies, government agencies and airports.

"It used to be that office jobs offered more flexibility," Gann says. Office workers had more variety and flexibility in their jobs and moved around more than, say, assembly line workers.

"Now so many things can be done on those terminals that more and more people are in jobs where they're wedded to the terminal." Gann spoke last week at a seminar on office health problems, sponsored by the Hamilton Clinic, the D.C. Lung Association and several labor groups.

Of the 39 million jobs added to the nation's labor force between 1947 and 1980, 33 million were in the service sector -- retail sales, financial services, health, education, data processing and other nonindustrial work.

"We're at the beginning of a revolution in office technology and information processing," says Darryl Alexander, a health and safety specialist with the Service Employees International Union (SEIU). "It's a growing industry.

"We don't want it to become the sweat shop of the 21st century."

Industrial hygienists single out several health issues with particularly widespread application to office workers: VDTs, lighting, indoor air pollution and stress.

A frustration for everyone involved -- employers, employes, health specialists and equipment manufacturers -- is the dearth of solid scientific data on office health problems, including stress. Office health is a relatively new specialty of public health.

SEIU's Alexander says it's "appalling" how little health research has been done on office workers. "It's at a very primitive level at this point."

Labor groups long have raised concern about possible hazards of the very-low-frequency non-ionizing radiation emitted by VDTs. They have cited clusters of cases of pregnancy complications -- such as miscarriages -- in women who work with VDTs constantly, but no scientific study has linked VDTs to miscarriages or birth defects.

The Computer and Business Equipment Manufacturers Association, an industry group, opposes requiring radiation shields for VDTs, calling them "a very poor idea."

"There's no reason for shielding because there are no harmful emissions coming from VDTs," said the association's president, Vico Henriques, in a statement last week.

Radiation levels from VDTs "have been found to be less than those emitted by hair dryers, irons and other typical household appliances," the director of the National Institute for Occupational Safety and Health (NIOSH), J.D. Millar, told a congressional panel last year.

When energy conservation became a priority for architects and builders after the oil embargo 12 years ago, airtight buildings and nonopening windows lost their ability to "breathe" and to clear stale or polluted air. In the trade, it's known as "tight-building syndrome." Indoor air pollution, which was virtually unheard of a decade ago, has become a major public health issue, linked to allergic reactions and respiratory illness.

Stress is a fact of life, but it remains a controversial topic because it is hard to measure and its health effects are not fully understood. It is defined as the biological response to the demands of the environment -- for example, an increase in the pulse rate, or a headache.

"It's a normal human response," says Robin Fratkin, an attorney and public policy fellow with the AFL-CIO. "What's abnormal is when we're constantly exposed to stress and we're not giving our bodies a rest."

Fratkin says secretaries and sales clerks suffer more office stress than most executives, adding that it can lead to problems such as overeating, insomnia and alcoholism.

Office workers can help relieve job stress by exercising regularly and learning ways to relax, such as meditation, deep breathing or biofeedback, she says.

Studies have shown that VDT workers, more often than non-VDT workers, complain of headaches, back, shoulder or wrist pain and eye strain, says Kevin Murphy, a technology specialist with the American Federation of State, County and Municipal Employes (AFSCME).

The good news, Murphy says, is that many of those health problems can be eliminated or reduced by proper design of office furniture, equipment and schedules.

"The basic lesson of design comes down to adjustability, to fit the range of workers," Murphy says.

That means chairs that are adjustable in height and tension, VDT screens that tilt and swivel, and detachable keyboards -- all of which allow the user to control and shift positions during the work day.

"Now that we have a radically new technology in the office," Murphy says, "these offices need to be redesigned." In addition to adjustable furniture and VDTs, office lighting should be less intense and more localized to reduce glare off the VDT screens, he says.

To relieve eye strain and vary the physical repetitiveness of keyboard work, NIOSH recommends at least a 15-minute break from the VDT screen every two hours. The break need not be a complete rest; workers can perform some other type of task before returning to the VDT.

O ffice health problems are difficult to diagnose, difficult to study and frusO trating to treat, says epidemiologist Gann. Typically they involve chronic ailments, such as headaches or eye strain, which are not "curable" by medicine or surgery.

Although traditional medicine has underemphasized office health problems -- because they resist simple labeling, treatment and cure -- Gann sees an equal danger in "overmedicalizing" them. Just because a worker lacks clear symptoms of acute illness doesn't mean chronic headaches aren't a serious problem, for example.

"We could confine ourselves to looking at only the tip of the iceberg," Gann warns, "because many of these things are beneath the levels of medical detection."