Greenpeace activists are headed to the Arctic this summer to protest oil and gas exploration but the environmentalists could inadvertently harm marine mammals and pollute the very environs they seek to protect, critics say.

The activists plan to shadow Royal Dutch Shell’s drilling ships in the coming weeks when they head into the Chukchi and Beaufort Seas off the northern Alaskan coast to drill two exploratory wells.

Despite a restraining order by the U.S. District Court for Alaska directing Greenpeace not to come within a mile of Shell, the activists will rush into the fragile setting aboard a 237-foot ice-cutter with militaristic surveillance equipment, including an unmanned air drone and two submarines.