Lawyers for the Federal Emergency Management Agency discouraged officials from pursuing reports of dangerous levels of formaldehyde in trailers housing thousands of hurricane victims, according to documents subpoenaed by House members and released Thursday.

Lawmakers called the actions sickening and infuriating at a hearing that included dramatic testimony from three trailer occupants whose families suspect formaldehyde is to blame for their various illnesses.

Both Democrats and Republicans bitterly criticized FEMA's decisions to conduct limited inspections or tests of trailers whose occupants reported various respiratory problems. The House Committee on Oversight and Government Reform subpoenaed FEMA records showing that agency lawyers warned officials there could be liability problems if formaldehyde tests suggested negligence on the government's part.

"It's sickening and the exact opposite of what government should be," said committee Chairman Henry Waxman, D-Calif. "It is impossible to read the FEMA documents and not be infuriated."

FEMA administrator R. David Paulison apologized to the trailer occupants.

"This agency made the best decisions it could with the information it had," Paulson testified. "Now we know we have to do something different than we've done in the past."

Formaldehyde, sometimes found in building materials used in manufactured homes, can cause respiratory problems and possibly cancer in high doses. FEMA provided more than 120,000 trailers to victims of the 2005 hurricanes Katrina and Rita, and many thousands still occupy them, especially in Louisiana, Mississippi and Arkansas.

When complaints of possible formaldehyde poisoning surfaced in early 2006, FEMA officials tested one occupied trailer and announced "there is no ongoing risk" for trailer users. But documents show the levels of formaldehyde found were higher than those considered safe by several government health and environment agencies.

The committee unearthed documents in which one FEMA lawyer advised: "Do not initiate any testing until we give the OK.... Once you get results ... the clock is running on our duty to respond to them."