It's not clear how much diesel fuel was spilled after a U.S. Army Reserve vessel ran aground near Kodiak Friday night.

A Coast Guard spokesman says the investigation continues and that the worst-case scenario is more than 15,200 gallons.

The Coast Guard has said the vessel, the Monterrey, hit Humpback Rock around 10:15 p.m. Friday, and that crew members purposely beached the vessel on Puffin Island to keep it from sinking.

On Monday, the agency said that two areas were identified for cleanup after a shoreline assessment. The Coast Guard says absorbent pads will be used to clean as much fuel from these areas as possible.

Containment booms also have been established around the Monterrey and the Coast Guard says absorbent material on the booms is being replaced regularly.