The Occupational Safety and Health Organization limits exposure in the workplace, up to .75 parts per million for an eight-hour day, but the EPA says that at air levels of .10 or above, "acute health effects can occur."
OSHA regulations say that formaldehyde is "reasonably anticipated to be a human carcinogen," and is sometimes associated with nasal and sinus cancer.
Lawsuits, new regulations and the advent of safer home building materials limited the use of formaldehyde by the early 1990s, and trailer manufacturers said they would voluntarily comply, Godish says.
But in 2006, the Sierra Club began receiving health complaints from hundreds of displaced Hurricane Katrina victims who were living in cheaply constructed trailers provided by FEMA.
When the environmental group began testing the air quality, it found 83 percent of the trailers had levels three times higher than the EPA limit.
The Sierra Club has set up a Web site for complaints and, those who experience problems can purchase a test kit to see if their housing units have high formaldehyde levels.
"FEMA housing units should come with a warning sign: Hazardous to your health," said Bill Corcoran, Sierra's regional representative in Los Angeles. "Fire survivors shouldn't be victimized by their own government."