ANCHORAGE, Alaska - An environmental group has filed a formal notice that it will sue the Environmental Protection Agency and the Coast Guard for authorizing oil dispersants without studying how they'll affect Alaska's polar bears, Cook Inlet beluga whales, Steller sea lions and other imperiled species.

The Center for Biological Diversity sent the agencies the 60-day notice Wednesday, a requirement before a lawsuit may be filed. The environmental group's Alaska director, Rebecca Noblin, said the lawsuit also will touch on other flaws in the state and federal spill response plan, such as the effects on wildlife of burning oil spilled in water.

"We focused on dispersants in the wake of the gulf disaster, where they used unprecedented amounts of dispersants without really knowing what the impact would be," she said. "That caught our attention.

"Nearly 2 million gallons of dispersants were dumped into the Gulf of Mexico," she said.

Federal agencies were closed Thursday for Veterans' Day and could not be reached for comment.

The Endangered Species Act requires federal agencies to ensure that their actions are not likely to jeopardize a threatened or endangered species or their habitat, Noblin said.

Dispersants are "preauthorized" by the Coast Guard and the EPA for use some Alaska waters, she said, including parts of Cook Inlet and Prince William Sound. Spill responders would need only to consult with the Interior Department "when practicable" for the areas.

Dispersants, designed to break apart oil, could be used elsewhere in Alaska if agency officials agree.

Noblin said the chemicals spread through the water and may be more harmful to marine life than untreated oil. Their short- and long-term effects have not been adequately tested, she said.

Studies indicate dispersed oil damages the insulating properties of seabird feathers more than untreated oil, making them more susceptible to hypothermia and death, she said. Other studies have found that dispersed oil is toxic to corals, fish eggs, larvae and adults and can harm marine mammals' ability to breathe.

"If the federal government cannot ensure that dispersants will not pose undue risk to struggling species in Alaska, it has no business authorizing their use, she said.

She acknowledged that once oil hits the water, there are no good solutions, which is why her group has sued previously to require the federal government to take a hard took at drilling before it's approved.

"When you're looking at dispersing and burning and skimming, there are all sorts of environmental trade-offs for these response methods," she said.