Three days after the U.S. Interior secretary announced he would loosen the Endangered Species Act, wildlife organizations and even an Interior spokesman couldn't explain what effects the rule change might have.

On Monday, Interior Secretary Dirk Kempthorne said he would propose a change in the landmark 1973 act that would allow agencies to decide for themselves whether projects they were supervising would harm endangered plants and animals. If the rule takes effect, federal agencies no longer would have to get the U.S. Fish and Wildlife Service or National Marine Fisheries Service to check their plans.

Conservationists aren't sure what that would mean in the near term for species such as the black-footed ferret or Winkler cactus, both endangered in Utah.

But the Bush administration proposal would eliminate an important part of the system of checks and balances, said Bob Davison of the Oregon-based Defenders of Wildlife.

Under current law, for example, the Bureau of Land Management has to do a biological assessment as part of environmental study of any project. The BLM consults with the Fish and Wildlife Service, which may offer suggestions or point out errors. Government wildlife scientists undertake tens of thousands of such reviews every year.

"If they know someone else is going to look at their work," Davison said, "BLM will take more care because [the biological study] is going to get a look from Fish and Wildlife."

Laura Romin, an assistant Fish and Wildlife supervisor in Utah, said the agency's public-affairs office declined to comment on the rule change. But Davison predicted it would lead to more lawsuits, putting courts in charge of scientific decisions.

During a telephone news conference Monday, Kempthorne characterized the rule change as "narrow" but at the same time said agencies handling big projects such as dams and highways would be allowed to make unilateral decisions regarding species harm.

Interior spokesman Chris Paolino said the rule wouldn't allow agencies to harm an endangered species.

"This is not a get-out-of-jail-free card," he said. "If a project could affect the black -footed ferret, there still has to be a consultation [with federal scientists]."

But he didn't know where in the environmental-review process the agencies would be able to declare there would be no harm to a listed animal or plant. Nor could he say what would happen if a project ended up causing harm or how that could be determined.

* The Associated Press contributed to this story.

Endangered species in Utah

Utah is home to more than 40 endangered animals and plants, including the Virgin River chub, the Utah prairie dog, the June sucker, the desert tortoise, the Uinta Basin cactus and the autumn buttercup.

Source: U.S. Fish & Wildlife Service