THURSDAY, Nov. 6 (HealthDayNews) -- Formaldehyde, the pungent chemical used in everything from insect preservation to film manufacturing, may boost rates of leukemia in exposed workers, a major federal analysis finds.

And a new study from the United Kingdom suggests such workers also face a greater lung cancer risk from formaldehyde exposure, although they only face a tiny risk of some rarer cancers.

While the U.S. researchers acknowledge other studies haven't been as definitive about the potential risk, the new reports are certain to fuel the debate over the use of the chemical in American factories. Federal regulations have limited exposure to formaldehyde since the 1980s.

However, some experts continue to call for less research and more restrictions.

"We need more science like we need a hole in the head," says Dr. Samuel S. Epstein, professor emeritus of environmental and occupational medicine at the University of Illinois School of Public Health.

For the U.S. study, Michael Hauptmann, a biostatistics researcher at the National Cancer Institute, and his colleagues launched the largest-ever analysis of formaldehyde exposure. They examined the medical records of 25,619 workers who began working with formaldehyde before 1966 at 10 industrial plants. Researchers followed the workers through 1994.

Those exposed to high levels of formaldehyde were up to 3.5 times more likely to develop leukemia than those at the lowest levels. In total, 69 of the those workers died of leukemia.

While the number of deaths is small, the link between formaldehyde and leukemia is important, Hauptmann says.

"The study definitely suggests that exposure should be kept to a minimum in the workplace and the environment," he adds.

The number of American workers exposed to formaldehyde on the job appears to be unknown, but federal officials estimated the number at 1.5 million from 1981-1983.

Most of the workers are exposed to formaldehyde during various types of manufacturing, including the production of particle board, plywood, plastic and photographic film, Hauptmann says.

Scientists and pathologists also work with formaldehyde, which acts as a preservative and gives laboratories their distinct smell. Other uses include the manufacture of permanent press clothing, embalming fluid and cosmetics.

"It usually comes in a liquid form from which solutions are prepared," Hauptmann says. "Then there is formaldehyde gas released that you can inhale."

His findings appear in the Nov. 5 issue of the Journal of the National Cancer Institute.

In the other study, which appears in the same issue, researchers in the United Kingdom examined the medical histories of 14,014 British men who were exposed to formaldehyde after 1937. The study had been completed in the late 1990s, but the researchers extended it to 2000.

Research in animals has suggested that formaldehyde could contribute to two rare types of nasal cancer, but the number of deaths from them -- three -- were actually lower than those that would have otherwise been expected. However, the workers were up to 1.6 times more likely to die of lung cancer.

It's not clear how formaldehyde may lead to leukemia and lung cancer. One possibility is that the chemical launches itself into the body on tiny particles in the air and then works itself free to create damage, Hauptman says.

Epstein says both findings are "more than enough to warrant the toughest regulatory proposals."

More information

To learn more about the use of formaldehyde in industry, visit the Occupational Safety & Health Administration or try the New York Committee for Occupational Safety & Health.