The book you want  is the anthology called

THIS FILM IS DANGEROUS, edited by Roger Smithers, assembled for the 2000
FIAF symposium on nitrate film.  Here you'll find a number of case
studies about film fires.  (General conclusion:  most theater fires were
NOT caused by nitrate film catching fire, but by a variety of other
factors.)

The most infamous early film-related fire was in Paris in 1897, killing
over 100 people.  It wasn't in a theater per se, but at a Charity
Bazaar's cinema pavillion.

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University of Alabama: http://www.tcf.ua.edu