2 of 2 people found this helpful
There are several write-ups on the fire, including detailed timelines and recovery efforts, but it does not appear a cause was ever identified:
- The 1973 Fire, National Personnel Records Center | National Archives
A good reminder of the importance of multiple copies when it comes to preserving history (or at least the information documented by records - no copy can really replace the visceral reality of the past one feels when working with an actual original document...) If even the National Archives themselves can have something like that happen, it's inarguable that redundancy is the only hope for truly long term records survival.
Just looking at those photos of warped shelves with ashes on them makes me want to go down to the D.C. archives and do more Citizen Scanning ...