Two-and-a-half years after Hurricane Katrina devastated New Orleans and parts of Mississippi, those displaced by the storm are being moved again -- this time because of high levels of formaldehyde in their temporary homes. Travel trailers provided by FEMA have tested positive for the carcinogen, and in some cases the levels are high enough to cause breathing trouble in those without respiratory issues.

People currently living in the trailers will be moved to hotels, apartments, and in studier mobile homes. It's not clear whether the formaldehyde issue is a problem in the FEMA trailers alone, or in travel trailers in general. Either way, FEMA is discontinuing use of travel trailers for emergency housing.

After Hurricane Katrina, 144,000 trailers were used to place victims of the storm. Currently, there nearly 36,000 trailers in use in Louisiana and Mississippi.