‘Black sludge’ found in fuel filter deemed cause of ferry power failure

We now know why a Washington state ferryboat ran aground on Bainbridge Island earlier this year.

According to a report from Washington State Ferries (WSF) multiple media outlets linked to, the M/V Walla Walla lost propulsion on its run between Bremerton and Seattle Saturday, April 15 because the fuel filters were clogged with bacteria and fungus.

More from WSF: Bremerton-Seattle ferry out of commission due to damaged propeller blade

The investigation between the U.S. Coast Guard and WSF concluded contaminated fuel led to a failure of both the generator and its backup systems, causing the boat to lose power.

According to WSF, the ferry ran aground around 4:30 p.m. while on the way to Seattle. Initial indications are the ferry suffered a generator failure. The report goes on to say the material got into the filters from some black sludge that had accumulated at the bottom of one of the so-called day tanks that hold oil and water for the vessel.

“This water contamination resulted in gross bacterial and fungal growth to the extent that the fuel filtration system was overcome, and the ships service diesel and vital generator engines could not function,” the report said.

Of the 13 sites around the boat that were tested, five showed signs of bacterial fungal growth.

An investigation also concluded crew fatigue was not a factor in the grounding. Drug and alcohol tests from the crew all came back negative as well.

More on ferries: Service to the San Juan Islands resumes after weekend ferry accident

All 596 passengers, 15 crew members and 175 cars were evacuated from the ship and given free food from the galley while they were stranded. No one was injured in the incident.

WSF confirmed all fuel on board the vessel tested clean while new monitoring gauges have been installed. They will also be administering more biocide to limit bacterial and fungal growth, as well as introducing more training and procedures to monitor fuel systems.