New Orleans ? The Federal Emergency Management Agency is barring employees from entering thousands of stored travel trailers over concerns about hazardous fumes, while more than 48,000 other trailers continue to be used by hurricane victims in Louisiana and Mississippi.

FEMA is advising employees not to enter any of the roughly 70,000 trailers in storage areas across the country, but the directive does not apply to other trailers still in use, agency spokeswoman Mary Margaret Walker said Thursday.

Many trailer occupants have asked to be moved because of concerns about formaldehyde contamination, and hundreds are suing trailer manufacturers, accusing the companies of jeopardizing their health by providing FEMA with poorly constructed campers.