Federal officials issued trailers to Hurricane Katrina victims even though some workplace safety tests detected high levels of formaldehyde at government staging areas for the structures just weeks after the storm, a lawyer for hundreds of occupants said Wednesday, according to the Associated Press.

Documents from OSHA raise new questions about how much federal officials knew about the units, which were sent to tens of thousands of displaced residents, said attorney Anthony Buzbee. But the documents don't say whether the tests in the weeks after the August 2005 storm were conducted inside or outside the trailers.

The Federal Emergency Management Agency, which issued the trailers, has been moving residents out for several months because of health complaints.

Recent tests on hundreds of FEMA trailers and mobile homes in Louisiana and Mississippi found formaldehyde levels about five times what people are exposed to in most modern homes, the U.S. Centers for Disease Control and Prevention announced last month.

At its peak, more than 143,000 trailers were in use by Katrina victims across the Gulf Coast. About 34,000 are still occupied, according to AP.

Buzbee said he reviewed a 10-page summary of test results from air sampling at FEMA staging facilities in Mississippi that found formaldehyde levels exceeding maximums set for federal workplace safety. Buzbee said the documents show some tests were performed as early as Oct. 11, 2005, and as late as Jan. 17, 2006.

"This is astonishing," Buzbee said Wednesday in an interview. "How could they feign ignorance that this was an issue even before they sent these trailers to residents?"

It was unclear whether the tests were performed by OSHA or FEMA.

Formaldehyde, a preservative commonly used in construction materials, can cause respiratory problems and is believed to cause cancer.

FEMA lawyers had discouraged officials from investigating residents' health complaints because of liability concerns, according to documents released by a congressional panel in July 2007.

Buzbee wrote about the test results in a letter Wednesday to Louisiana Gov. Bobby Jindal and several members of Congress.

Adam Sharp, a spokesman for Sen. Mary Landrieu, D-La., said the information provided by Buzbee will be fodder for a congressional panel's review of FEMA's response to formaldehyde concerns.