The village of Kivalina is trying to figure out why a rust-colored substance washed on shore starting Wednesday night.
Pictures sent by city administrator Janet Mitchell show an orange sheen across the surface of a nearby lagoon, just feet from houses.
Officials don’t know what it is or where it came from -- though the Coast Guard said initial tests indicate the residue is of natural origin.
"It is not man made, it is not a petroleum substance," said Petty Officer David Mosley.
Mosley said incident commanders are awaiting further tests, but that the substance might be a type of algae.
Kivalina is located in a mineral-rich region on Alaska’s northwest coast about 46 miles downstream from the Red Dog Mine, a zinc mine and major economic engine in the region.
"We’re not aware of any aspect of our operation that could be responsible," said Wayne Hall, the mine's manager of community and public relations.
Hall said Red Dog flew community members in a helicopter over the affected area last night and took samples.
He said the mine is arranging a second flight and hopes to send the samples to a lab for further review.
"We’re just trying to help the community identify what this might be," Hall said.
Contact Ted Land at firstname.lastname@example.org