More than two years after residents of FEMA trailers deployed along the Mississippi Gulf Coast began complaining of breathing difficulties, nosebleeds and persistent headaches, U.S. health officials announced Thursday that long-awaited government tests found potentially hazardous levels of toxic formaldehyde gas in both travel trailers and mobile homes provided by the agency.

The Federal Emergency Management Agency, which requested the testing by the U.S. Centers for Disease Control and Prevention, said it would work aggressively to relocate all residents of the temporary housing as soon as possible.

Levels of formaldehyde gas in 519 trailer and mobile homes tested in Louisiana and Mississippi were — on average — about five times what people are exposed to in most modern homes, the CDC reported. In some trailers, the levels were nearly 40 times customary exposure levels, raising fears that residents could suffer respiratory problems and potentially other long-term health effects, it said.

At a news conference Thursday in New Orleans, CDC Director Dr. Julie Gerberding urged FEMA to relocate residents before summer, when heat would be expected to cause the formaldehyde levels to increase, with priority given to families with children, elderly people or anyone with asthma or other chronic conditions.

FEMA Director David Paulison, who also spoke at the news conference, said he believed his agency could meet that goal despite a shortage of affordable housing plaguing areas of the Gulf Coast afflicted by Hurricanes Katrina and Rita in 2005.

“We’re going to work very hard to meet their recommendations,” he said.

38,000 families still in FEMA units

He estimated that approximately 38,000 families — or roughly 114,000 individuals — are currently living in FEMA-provided travel trailers or mobile homes along the Gulf Coast, down from a high of about 144,000 families.

Paulison also defended FEMA’s response to the problem, which surfaced in late 2005, when some travel trailer occupants began reporting breathing difficulties, headaches and nosebleeds.

“I think we have moved very quickly based on what we knew,” Paulison said Thursday. “… We did the best we could do with the information we had.”

The Sierra Club began warning about formaldehyde levels in travel trailers by early 2006, after conducting its own air-quality tests. FEMA officials initially dismissed the environmental group's testing, saying the trailers conformed to industry standards.

Formaldehyde is used in a wide variety of products, including composite wood and plywood panels used to manufacture the thousands of travel trailers and mobile homes purchased by FEMA after the storms.

There are no federal safety standard for formaldehyde fumes in homes or travel trailers, though the Department of Housing and Urban Development regulates the presence of the chemical in the manufacture of mobile homes.

In addition to causing respiratory ailments, formaldehyde is considered a human carcinogen, or cancer-causing substance, by the International Agency for Research on Cancer and a probable human carcinogen by the U.S. Environmental Protection Agency.

FEMA already had been relocating families living in travel trailers or mobile homes who expressed a desire to move out because of formaldehyde concerns, but the agency will now move to quickly close down all remaining group sites, which house approximately 8,000 families, and relocate them to apartments or, temporarily, to hotels or motels, Paulison said.

Asked how much the relocation effort might cost, he replied, “It really doesn’t matter. … We’re going to move aggressively to get them into decent housing.”

Shortage of affordable housing

The massive relocation will be complicated by a severe shortage of affordable housing in along the Gulf Coast.

In New Orleans alone, Hurricanes Katrina and Rita destroyed 41,000 apartments affordable to people earning less than the area's median income, according to the Oakland, Calif., think tank PolicyLink.

Paulison said it had not yet been decided whether the agency would force residents living in FEMA trailers or mobile homes on private property — such as homeowners overseeing the rebuilding of a house — to leave.

He also vowed that FEMA would no longer use travel trailers to house disaster victims.

“We will not ever use trailers again,” he said. “... That is not a good housing alternative for us.”

He said FEMA would continue to distribute mobile homes to disaster victims, including people left homeless by last week's tornadoes in Arkansas and Tennessee, but will test all units for formaldehyde prior to occupancy.

The reason for the persistently high levels of formaldehyde in the units has never been explained, though some experts have speculated that manufacturers may have run out of “low-emission” building products in the rush to meet post-hurricane orders for thousands of travel trailers and mobile homes.

Paulison said his agency and CDC experts are “taking some of these travel trailers apart to see what’s causing this.”

Waxman identifies three manufacturers

Gerberding said the testing, which she described as preliminary, had not identified specific types or brands of trailers or mobile homes that had higher levels of formaldehyde.

But Rep. Henry Waxman, D-Calif., the chairman of the House Committee on Oversight and Government Reform, who has been investigating the formaldehyde problem, indicated for the first time on Thursday that his panel has developed “specific evidence” that travel trailers and mobile homes supplied by three manufacturers contained high levels of the toxic gas.