WASHINGTON (AP) — The Federal Emergency Management Agency manipulated scientific research in order to play down the danger posed by formaldehyde in trailers issued to hurricane victims, according to an investigation by congressional Democrats released Monday.

FEMA "ignored, hid and manipulated government research on the potential impact of long-term exposure to formaldehyde" on Katrina and Rita victims now living in FEMA trailers, Democrats on a House Science and Technology subcommittee wrote in a letter to Homeland Security Secretary Michael Chertoff. FEMA is part of the Homeland Security Department.

In a separate letter, lawmakers said the federal health agency that provided guidance to FEMA was "complicit in giving FEMA precisely what they wanted."

Victims living in FEMA trailers have complained of health problems related to formaldehyde, but initial FEMA tests revealed the air quality in the trailers was safe if those trailers were properly ventilated.