As use of formaldehyde increases, so do concerns over its safety. It's in glue, plywood, plastics and carpet, for instance.
Chemists learned how to make formaldehyde in the mid-1800s. One of its earliest uses in the United States was to preserve corpses shipped home from the Civil War.
But early in this century, industry discovered the chemical could be used to make plastics. And by the 1970s, it was showing up in everything from foam insulation to construction glue.
Thad Godish, an expert on indoor air quality at Ball State University in Indiana told the NPR radio station, "I could go into any house and I can find a formaldehyde-releasing product," says. He says scientists have known for a long time that it could cause health problems.
"Formaldehyde is a potent irritant," he says. "It's going to irritate the eyes, nose and throat. And one of the things that formaldehyde also causes is fatigue. It just wipes you out. You feel tired all day long. You feel like you haven't gotten a good night's sleep, and maybe you didn't, because it also interferes with sleep."
It can also cause asthma attacks, and long-term exposure is linked to cancers of the nasal passages and sinuses.
In February last federal health officials in US urged Katrina victims to move out of trailers supplied by the Federal Emergency Management Agency
( FEMA) after tests showed dangerous levels of formaldehyde fumes.
Tests by the Centers for Disease Control and Prevention on more than 500 trailers in Louisiana and Mississippi showed formaldehyde levels that were five times higher than levels in a normal house. The levels in some trailers were nearly 40 times what is normal.
The CDC said people should move out quickly — especially children, the elderly and anyone with asthma or another chronic condition. Warmer temperatures could increase formaldehyde levels, and CDC officials said they wanted residents to move out of the trailers before summer.
Formaldehyde is a toxic chemical used to manufacture mobile homes. A CDC director said the high levels can cause burning eyes and breathing problems for people with asthma and those sensitive to air pollutants.
FEMA provided about 120,000 trailers in the aftermath of Hurricanes Katrina and Rita in 2005. By 2006, many people were complaining of nosebleeds, headaches and other illnesses. Some of them testified before Congress last summer, and at least 1,000 families have asked FEMA to move them.
Consequent on several lawsuits, formaldehyde emissions from a typical household product had decreased by more than 70 percent between 1980 and 1990.
Today, the formaldehyde in consumer products such as glue tends to stay put — except under certain conditions.
"You increase the temperature, it starts to break down. You increase the relative humidity, it starts to break down. And if you increase both the temperature and the relative humidity, you have lots of formaldehyde released," Godish warns.