A jet fuel spill at  Oakland Airport on Monday sent hundreds of gallons of fuel onto the tarmac and into a storm drain, according to state officials and airport authorities.

The spill happened around 10 a.m. during engine maintenance on a UPS plane, according to an incident report from the California Governor’s Office of Emergency Services. The report said 200 to 250 gallons of aviation fuel were released onto the tarmac. An unknown amount entered a storm drain that connects to the San Francisco Bay.

“The leak was immediately stopped, and all protocols and procedures were enacted to address the issue, including shutting off nearby water pumps to ensure no materials reached the Bay,” airport spokesperson Kaley Skantz said in a statement. “The leaked fuel was contained in the storm drain and will not reach the Bay.”

Port environmental safety staff and the Oakland Fire Department responded to the scene, according to the airport. Fire crews worked to contain the spill, and cleanup efforts were underway Monday.

No injuries were immediately reported.

It was not immediately clear Monday afternoon whether any outside environmental regulators were investigating.

The incident comes as airlines worldwide face volatile jet fuel supplies and rising costs tied to conflict in the Middle East. The International Air Transport Association warned this month that airlines could begin seeing jet fuel shortages by late May, and some have already cut flights as fuel prices climb.