An ocean advocacy group’s chief scientist says worms at the likely site of an underwater abandoned oil well left black “castings” on the sandy mound above it, rather than the usual white wormholes.

Oceana’s Michael Hirshfield says this isn’t proof the well is leaking and the wormholes are oil stained, but he said the find in 250 feet of water south of Gulf Shores, Ala., is intriguing.

Earlier this summer, an Associated Press investigation found more than 27,000 aging, abandoned wells are not being checked for leaks.

Scientists on the Oceana Latitude sent a remote-controlled underwater robot to photograph the sea floor around the location south of Gulf Shores as part of a mission to chart areas possibly at risk in future oil spills.

They’re about two weeks into a two-month research trip.