Tustin Hangar One Burns

According to the Orange County Fire Authority (OCFA), crews were called to the former Tustin Air Base around 12:55 a.m. PST on Tuesday. When crews arrived, they found the north hangar, one of two megastructures built to house blimps during World War II, was fully engulfed.

More than 70 firefighters were called to the scene. At one point, ground crews were aided by water-dropping helicopters. Fire officials did not want to perform an internal attack as there were concerns about the roof collapsing. This proved to be correct, and tweets posted by the OCFA show photos of a collapsed roof. No firefighters were inside the building or injured.

The building and south hangar made from Douglas fir, are on the National Register of Historic Places as two of the world's largest free-standing, wooden structures.

The hangars are approximately 1,072 feet long by 292 feet wide and 192 feet—or 17 stories—tall. Arranged in a V formation, they were designed to hold six blimps at a time. After WWII ended and airship operations were phased out, the facility became a Marine Corps Air Station and was used for helicopter operations up through Vietnam. Military operations were phased out in the 1990s and the base was slated for closure, although many of the buildings still remained in use for civilian aviation purposes. According to Tustin Legacy, both the north and south hangars are still owned by the Department of the Navy, although the site ceased being a military base in 1999. Much of the former base became residential housing.

Arson investigators are on the scene, and no cause of the fire has yet been determined.

At a news conference Tuesday morning, Orange County Fire Authority Chief Brian Fennessy noted that the property does belong to the U.S. Navy and that the investigation will eventually be turned over to it.