The warehouse fire occurred in early 1978 at a New Jersey storage facility Atlantic was using to house session reels (they kept the master mono and stereo takes of released material in New York, for ease of use in licensing or for their own albums). Since the tapes were insured, Atlantic wasn't out any money at the time, but of course, with CD reissues later on, so much that could have been heard is forever lost, and of course, any multitracks that were there are gone too.
The big question fans have been asking all these years: what was or wasn't stored at that warehouse? We know that the session tapes for LAYLA never got that far, and probably some others, but what I don't think has ever been revealed is a list of what was known to be there. We can surmise that since the only Aretha extras on Atlantic reissues are mono mixes or versions folded from quad (like "Chain Of Fools"), her session tapes are gone (as are most of Ray Charles; but as Bill Holland reported in Billboard in 2005, Jerry Wexler had a dub of some material made for him by Tom Dowd, and some of that material was later used for a Rhino box set). It's also believed the Led Zeppelin studio multis exist, as Jimmy Page sent along only the final stereo mixdowns. Others may have done the same--Crosby, Stills, Nash & Young, for instance, let's hope other acts kept hold of the session reels as well, at least there's a chance for future MC releases if anyone's up to it.
ED