Ron Mason, owner of a disaster contracting firm, Alpha 1, said that in the past two weeks he had sold more than 20 of the trailers to cleanup workers and the companies that employ them in Venice and Grand Isle, La.

Even though federal regulators have said the trailers are not to be used for housing because of formaldehyde’s health risks, Mr. Mason said some of these workers had bought them so they could be together with their wives and children after work.

“These are perfectly good trailers,” Mr. Mason said, adding that he has leased land in and around Venice for 40 more trailers that are being delivered from Texas in the coming weeks. “Look, you know that new car smell? Well, that’s formaldehyde, too. The stuff is in everything. It’s not a big deal.”

Not everyone agreed. “It stunk to high heaven,” said Thomas J. Sparks, a logistics coordinator for the Marine Spill Response Corporation, as he stood in front of the FEMA trailer that was provided to him by a company working with his firm. Mr. Sparks said the fumes in the trailer from formaldehyde, a widely used chemical in building materials like particle board, were so strong that he had asked his employer to provide him with a non-FEMA trailer.

The trailers  which are being resold for $2,500 and up  started down their road to infamy after Hurricane Katrina in August 2005, when FEMA officials ordered nearly $2.7 billion worth of trailers and mobile homes to house victims of the storm.