"We're asking EPA to fulfill its obligations under the Endangered Species Act," said Rebecca Noblin, an attorney and spokeswoman for the Center for Biological Diversity.
Polar bears were listed as a threatened species in May 2008 because of the dramatic loss in their primary habitat, sea ice.
EPA spokesman Mark MacIntyre in Seattle said he had not seen the lawsuit and noted the agency generally does not comment on pending litigation.
Noblin claimed the U.S. has lagged other countries in protecting the Arctic from pesticides and other contaminants.
Pesticides are used minimally in Alaska but find their way to the Arctic by wind and ocean currents, Noblin said. They also move north in crustaceans, fish, marine mammals and migratory birds.
The case was filed in Seattle, headquarters for EPA Region 10, which covers Alaska.
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