The Tustin military hangar was declared fully extinguished after 24 days by the Incident Management Team.
After monitoring the piles of debris for the past 48 hours, no detectable hot spots were found within the hangar perimeter.
The Incident Management Team used infrared drone flights to seek out any hot spots that were left over beneath the fire debris.
The hot spots were turned over with excavators and personnel on the ground extinguished any remaining smoldering debris piles.
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The fire started on Nov. 7, destroying the historic World War II-era hangar at the former Tustin Air Base that was a significant part of Orange County's military history.
Two days after it caught fire, the EPA notified city officials that debris tested positive for asbestos and other dangerous chemicals.
Residents expressed concern over the lack of planning for such a historic hangar, built with materials known to have asbestos, as well as the lack of an emergency evacuation.
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The flare-ups caused many schools in the county to close throughout the extinguishing process.
The nearly 1,600-acre property was commissioned in 1942 and played a significant role in Navy and Marine aviation for half a century.