A Louisiana congressman is calling for hearings on the government's response to formaldehyde fumes in trailers provided to storm victims by the Federal Emergency Management Agency.

Earlier this month, the agency dismissed findings by environmentalists that the trailers pose serious health risks from the known carcinogen. The agency said the fumes could be reduced by opening vents and windows, a strategy deemed unacceptable by Rep. Bobby Jindal in light of the region's heat and humidity.

Jindal, a Republican widely expected to run for governor in the fall, sent a letter to House leadership Thursday calling for hearings, saying he was "astonished" by reports of dangerous levels of formaldehyde in the trailers.

"Further, case studies show that even if residents followed FEMA's guidelines on appropriate ventilation of trailers, high levels of formaldehyde can remain," Jindal said.

The formaldehyde is mostly contained in particleboard used in the trailers, from walls to cabinets.

FEMA has said that its trailers conform to industry standards and that the agency has found no reason to question their safety. A review of air samples from 96 new trailers by the Agency for Toxic Substances and Disease Registry shows that formaldehyde levels were noticeable, as with many other new products, but that the levels fall within safe levels in days if a trailer is ventilated, FEMA said.

However, FEMA has not conducted similar tests on trailers where people have been living for months since being displaced from their homes. The agency said there are 75,652 trailers still in use by victims of hurricanes Katrina and Rita in Louisiana, Mississippi, Texas and Alabama. The hurricanes slammed into the Gulf Coast within a month of each other in 2005.