San Francisco ? Most of the oil that spilled into San Francisco Bay when a container ship struck the Bay Bridge will never be retrieved and eventually will be absorbed into the ecosystem, authorities said Friday.

The U.S. Coast Guard, which was criticized for its response to the 58,000-gallon spill, acknowledged miscommunication but insisted it didn’t impede their efforts to corral the oil.

Tides carried the heavy fuel that poured from the ship’s oil tank under the Golden Gate Bridge and into the Pacific Ocean, fouling miles of coastline, closing several beaches, canceling weekend outdoor events and threatening thousands of birds and other marine life. It is believed to be the biggest spill in the bay since 1988.