Bryn Nelson reports on the continuing controversy over using formaldehyde in buildings.
The presence of formaldehyde in everything from embalming fluid and hair straighteners to plywood adhesives and varnishes has prompted toxicologists and other researchers to scrutinise the chemical’s potential health impacts on a wide range of adults.
One of the first studies to examine the effects on children, a 1979 survey of 275 potential cases of at-home exposure, found concentrations ranging from 0.1 to 3 parts per million in residents’ living rooms and bedrooms. Researchers documented eye, nose and throat irritation in about 60 per cent of the children they saw (75 per cent of adults) and coughing and wheezing in 70 per cent of the kids (double the percentage in adults).
In the decades since then, researchers say, stricter indoor air standards and lower formaldehyde levels in building materials and consumer products have afforded more protection to adults and children alike. The World Health Organization, for example, now recommends a 30-minute exposure limit of 81 parts per billion for the general public, to prevent sensory irritation.
But further efforts to reduce the gas in new classrooms and other buildings have met stiff resistance. Industry groups like the Formaldehyde Panel assert in adverts that the chemical “is a natural part of our world” and have called it a “critical, commercially valuable, and basic building block in our modern society”.
Naturally occurring in low concentrations, formaldehyde’s reputation as a chemical irritant at higher concentrations is due in large part to its ready absorption by the mucous membranes that protect the eyes and respiratory tract. The European Chemicals Agency and the US National Toxicology Program have labelled it a “presumed” and “known” carcinogen respectively. In fact, researchers believe the gas can harm humans in three ways: as a carcinogen, as a toxin and as an allergen.
Evidence of a clear association between formaldehyde and asthma remains controversial; a 2011 research review by a US National Academy of Sciences panel cast doubt on suggested links to asthma, respiratory cancers, leukaemia and other health problems. The panel, however, agreed with the US Environmental Protection Agency’s conclusions that formaldehyde can irritate the eyes, nose and throat and cause respiratory lesions, as well as cancer in the nose, nasal cavity and upper throat.
Hal Levin, founder of the Building Ecology Research Group, based in Santa Cruz, California, believes that emissions of volatile organic compounds (such as formaldehyde) and semi-volatile organic compounds from building materials and furnishings are among the biggest contributors to poor indoor air quality in schools. Proper ventilation can help dilute the concentration of these pollutants, he says. But a far better long-term solution, he argues, is using materials that have eliminated them or greatly reduced their presence from the start. “The solution to pollution is not dilution,” he says. “It’s source control.”
Despite the growing evidence of harm, however, formaldehyde remains a common ingredient in building components ranging from fibreboard to flooring, particularly within mobile homes and portable classrooms. In the USA high levels of the chemical were discovered in emergency trailers used to house tens of thousands of people left homeless by Hurricanes Katrina and Rita in 2005. And from a recent specification sheet for portables used by Seattle Public Schools, local architects concluded that a typical building’s insulation, decking and wall sheathing all “most likely” contain formaldehyde.
The US Environmental Protection Agency has proposed stricter emission limits on composite wood products, but the rules have yet to be finalised after years of wrangling.
For Levin, the delay in minimising a known danger – especially in classrooms – comes down to values. “And I think the take-home message for schools is that we all profess to value children’s health and learning,” he says, “but we don’t put our money where our mouths are.”