Naval Special Warfare Command was investigating a battery fire Sunday night that damaged an Advanced SEAL Delivery System submersible at its Waipi'o Peninsula shore-based facility.

The 8:30 p.m. fire occurred during routine maintenance, which included battery recharging, the Navy said in a news release yesterday.

Federal firefighters put out the fire and continued to douse the mini-submarine with water to cool any remaining hot spots. No injuries were reported.

A hazardous material unit used thermal imaging equipment to monitor the area for hazardous gases and materials. No such materials were detected, Navy officials said.

The battery-powered vessel, known as an ASDS, is a combat submersible designed to clandestinely transport special operations forces from submarines. It is equipped with onboard communication and navigational equipment. The ASDS provides a dry environment and has greater speed, range and payload capacity than previous SEAL delivery vehicles.

The Navy did not disclose what caused the fire or the extent of damage to the ASDS.