The M/V Walla Walla ferry has returned to operating the Bremerton-Seattle route after it ran aground near Bainbridge Island due to contaminated fuel April 15.

The jumbo class ferry sailed off course and hit ground in Rich Passage during low tide. None of the 596 passengers or 15 crew members were injured, and all were successfully evacuated. The state Department of Ecology concluded that no pollution was detected as a result of the grounding.

The state Department of Transportation initially labeled the cause as a generator failure, but internal investigation and one headed by the U.S. Coast Guard found contaminated fuel caused the vessel to lose its generator and backup systems. That resulted in the loss of propulsion and steering controls, DOT officials said.

An investigation on how the fuel was contaminated is ongoing.

WSDOT announced it would take preventative measures on the Walla Walla and another vessel “to ensure a similar incident does not occur.”

All fuel currently on board has tested clean, Washington State Ferries tweeted, adding new, upgraded generator-monitoring gauges have also been installed on both the Walla Walla and the Spokane.