Formaldehyde: Some surprises at home.

It's hard to avoid exposure to formaldehyde, a respiratory irritant and suspected carcinogen. It protects latex paints from mildew and inhibits wrinkles in permanent-press fabrics. It's also a key ingredient in many insulating foams, durable automotive resins, and glued-wood construction materials.

A new study finds that although manufacturers have in recent years cut formaldehyde emissions from some of its most notorious sources--such as particleboard--many common consumer products still release copious amounts. Indeed, one of the big surprises was the amount coming from certain floor finishes, observes Thomas J. Kelly, a chemist who led the new analysis.

Under contract to the state of California, Kelly's team at Battelle Memorial Institute in Columbus, Ohio, measured 24-hour formaldehyde emissions from 55 domestic consumer and construction products. While polyurethane floor finishes don't emit the toxicant, he found, the more durable acid-cured resin finishes do. Until they dry, they can spew up to 1.2 grams per square meter per hour--nearly 1,000 times more than bare particleboard.

Moreover, he notes, refinishing a home's floors with this product could saturate other surfaces--walls, furniture, carpeting, even toys--with formaldehyde, allowing it to reenter the air long after the floors had dried.

Wet fingernail hardeners and polishes also proved to be big emitters. A 3-inch-square coating emitted far more formaldehyde--between 50 and 800 micrograms--than did an equal area of particleboard or veneer-covered plywood, the Battelle scientists report in the Jan. 1 ENVIRONMENTAL SCIENCE & TECHNOLOGY. While this can offer individuals--from fashion-conscious teens to professional manicurists--a big slug of the toxicant, nail treatments coat small areas and the exposures are short-lived. By contrast, plywood, particleboard cabinets, and new plastic-laminate counters not only cover relatively large areas but also emit measurable formaldehyde continuously for days to weeks.

Other major sources of formaldehyde included permanent-press shirts and draperies. While a single washing reduced a shirt's formaldehyde emissions by 60 percent, Kelly notes that draperies might never get washed. Pre-pasted wallpaper, while wet, also emitted substantial amounts of the toxicant--nearly 700 [micro]g per square meter per hour.

Kelly's data on the effect of washing permanent-press fabric "is nice information that we can pass along," notes Peggy L. Jenkins, who manages the Indoor Air Quality Program at California's Air Resources Board in Sacramento. The main use of the new data, she says, "will be to improve and revise our guidance to the public" regarding what to buy.

While the recommended exposure limit of 0.5 parts per million in air will not change, she says, "we have, with this new information, a little more meat and potatoes" on where big exposures may occur. For instance, she says, consumers may want to ask more questions about floor finishes or cabinet materials, instructing their contractor to use products that emit less formaldehyde.