Over 150 seabirds have been injured by a "mystery substance" and 20 have died so far, according to the San Francisco Bay Area's International Bird Rescue center, which is currently working to clean and save as many as possible.

SFGate reports that even California Department of Fish and Wildlife specialists aren't sure what, exactly, is in the "goo" that's harming the birds. IBR describes the contaminant as a "viscous substance that destroys feather waterproofing, which can cause hypothermia and death;" affected birds include Surf Scoters, Buffleheads, and Common Goldeneyes.

Advertisement

According to a press release on the organization's website:

"We have not seen this type of substance before, though preliminary tests have shown it is not petroleum-based," said Barbara Callahan, interim executive director of International Bird Rescue who served as bird unit leader during the 2010 BP oil spill. "Our veterinary and rehabilitation staff is working overtime to ensure all birds transported to us receive optimal emergency care."

SFGate dug into some theories as to what the non-petroleum-based substance might be, possibly "a synthetic rubber called polyisobutylene, a sticky, odorless substance" that killed "more than 4,000 seabirds along the southwest coast of England in 2013."

Advertisement

Department of Fish and Wildlife spokesperson Andrew Hughan told SFGate that further tests will be performed tomorrow, but that it's not believed the substance is toxic or harmful to humans.

"We know its not a public health or safety risk," he said. "It killed the birds because they froze to death. It sapped all the heat out of them. They were not poisoned. They died because of a loss of body heat."

"Obviously it's got pretty high priority," Hughan said. "It's a mystery for sure. It could be a day or two before we come up with something definitive."

Advertisement

Image via Cheryl Reynolds/International Bird Rescue.