WASHINGTON — An outbreak of one of the most contagious animal diseases from any of five locations the White House is considering for a new high-security research laboratory would be more devastating to the U.S. economy than from the isolated island laboratory where such research is now conducted, says a report published Friday.

The 1,005-page Homeland Security Department study said chances of such an outbreak — with estimated losses of more than $4.2 billion — would be "extremely low" if the research lab were designed, constructed and operated according to government safety standards.

Still, it calculated that economic losses in an outbreak of foot-and-mouth disease could surpass $4 billion if the lab were built near livestock herds in Kansas or Texas, two options the Bush administration is considering. That would be nearly $1 billion higher than the government's estimate of losses blamed on a hypothetical outbreak from its existing laboratory on Plum Island, N.Y.

The administration is studying the safest place to move its research on such dangerous pathogens from Plum Island to the U.S. mainland near herds of livestock, raising concerns about a catastrophic outbreak. A final choice is expected by late fall. The foot-and-mouth virus does not infect humans but could devastate herds of cattle, swine, lambs and sheep.

The five locations the U.S. is considering are Athens, Ga.; Manhattan, Kan.; Butner, N.C.; San Antonio; and Flora, Miss. A sixth alternative would be construction of a new research lab on Plum Island. That option is considered less likely because the administration spent considerable time and money scouting new locations and because of financial concerns about operating from a location accessible only by ferry or helicopter.

Economic losses in an outbreak would exceed $3.3 billion if the new lab were built in Georgia, North Carolina or Mississippi, the report said.

The Homeland Security official in charge of the study, Jamie Johnson of the Office of National Laboratories, said it sought to identify specific risks to each candidate location.

"What the EIS (environmental impact statement) concludes is that the likelihood of release of foot-and-mouth disease is extremely low," he said. "However, in the event that foot-and-mouth does get out, what does that mean to these sites?"

The new study concludes that risk would be low to nonexistent that an accident or terrorist attack would result in the outbreak of a dangerous pathogen at any of the sites except in case of a fire and explosion. Such a fire and explosion would pose a moderate risk that virus or disease could spread to nearby livestock or wild animals.

The threat from fire and explosion would be diminished for the government's isolated laboratory on Plum Island "due to the low likelihood of any disease getting off of the island," the report said.