The travel trailers that were provided to all of the idiots that wanted to stay in New Orleans after Katrina.
The trailers, just like all other travel trailers, have that "new trailer" smell, which just happens to be formaldehyde which is used in the paneling, carpets, fabrics, etc. The smell is supposed to go away if the trailer is properly ventilated.
An RV trailer purchased for recreational purposes with ones own personal money cannot be considered a formaldehwagen, even if the smell is present.
Formaldehwagons are only those trailers that were provided free-of-charge to the bunch of whining freeloaders in the Gulf Coast area who can't appreciate the government giving them a free home (again)
MAN: Beeatch, get yo badonkadonk into ouz guvment trailer a fetch me an' my homies some foaties.
WOMAN: I ain't goin' in der. Ouza FEMA trailer is toxified wid dat foam-era-cide!
MAN: Get yo fat ass into dat formaldehwagon and get me a foaty or I gunna pimp slap yo ass.