A new study, reported in the January 1, 1999, issue of Environmental Science & Technology, notes concern about indoor exposure to formaldehyde, a suspected human carcinogen. It details high formaldehyde emission rates from new permanent press shirts, as well as from nail hardener, floor finish, and certain wood products

"There had been no comprehensive look [at formaldehyde] for about 15 years," said Thomas J. Kelly, PhD, author of the study and chemist at the Battelle Memorial Institute in Columbus, Ohio. "In the 1980s, the Consumer Product Safety Commission did testing, but things have changed since then."

What Is Formaldehyde?

Formaldehyde is a colorless gas that dissolves in water. The substance is also used in products such as wood glue, insulation foam, leather, make-up, and embalming fluid, and is found in tobacco smoke.

Formaldehyde can cause skin rashes, allergies, and upper respiratory inflammation in humans. Some studies suggest a higher risk of cancer among people who work with formaldehyde. These groups include morticians, pathologists, and chemical workers.

Study Findings

The report tested products found in California homes and determined emission rates from 55 materials and consumer products. Findings revealed relatively high emissions ranging from bare pressed-wood materials made from urea-formaldehyde (UF) resins, and from new permanent press fabrics. An acid-cured floor finish released the highest emissions. Emissions from fingernail polish and hardener also were high.

"We made it as realistic as possible. We bought pants from J.C. Penney and paint at Wal- Mart, just as people in California would buy. Our purpose was to measure emissions rates for a large variety of products," Dr. Kelly added.

"Our one surprising finding was the number of products that have formaldehyde in them," he said. "Of the products we tested all had formaldehyde in them deliberately, not as a byproduct."

In addition to detailing emission rates from common products, the study determined formaldehyde emissions from UF wood products decreased when the wood products were coated with vinyl, paper, laminate, or other coatings. Emissions from permanent press shirts decreased significantly after they were washed once.

Materials and Consumer Products Tested

Products tested were selected based on four criteria: (1) the market share or quantity of the product produced; (2) the extent of the use inside homes; (3) the product’s likely or demonstrated emission rate; and (4) the potential intensity of exposure to users.

Dry construction products with high emission rates included UF particleboard and cabinet doors with a white acid-cured finish. Household products with high emission rates included new permanent press draperies, shirts, and sheets. Wet construction products with high emission rates included paint, wallpaper, and commercially applied floor finishes including base coats and top coats, with emissions from the base coat higher than emissions from the top coat. The study noted that since the floor finishes tested are applied only by qualified contractors, the exposure to the general public probably is less because of the lag time between application and exposure to residents of homes where the coats have been applied.

Dr. Kelly and colleagues recommended more research on surface coatings that reduce emissions from bare wood products, as well as additional study of human exposure to high formaldehyde emissions from products such as clothing, cosmetics, paints, and wallpapers. They added acid-cured finishes and a person’s activity patterns during application of wet products are important areas for more study.

Effect on Humans Unknown

It is important to study widely used products to make sure they are not carcinogens, said Michael Thun, MD, vice president of epidemiology and surveillance research for the American Cancer Society.

"One doesn’t want to repeat [the experience with] asbestos, and yet formaldehyde has been around for a long time. If there is a hazard from formaldehyde it has been sufficiently small so that it is not visible in the studies that have been done," Dr. Thun said.

Though rodents have developed nasal tumors after exposure to formaldehyde, humans don’t get these same tumors because of anatomical differences, he added. "This is an example where formaldehyde clearly is a carcinogen in this particular animal, but its relevance to humans is still very uncertain."