Tar sands oil coming up from the ground.

oil beds.
"The documents and photos show dozens of animals, including beavers and loons, have died,
and that [nearly 35 tons ] of oily vegetation has been cleared from the latest of the four spill zones. …
“Everybody (at the company and in government) is freaking out about this,” said the (anonymous) scientist.
“We don’t understand what happened.
Nobody really understands how to stop it from leaking, or if they do they haven’t put the measures into place.”
Via Grist