National Archives and Records Service film-vault fire at Suitland, Md. : hearings before a subcommittee of the Committee on Government Operations, House of Representatives, Ninety-sixth Congress, first session, June 19 and 21, 1979 (1979)

326 Before reviewing possible conditions under which nitrate film fires might occur in the film laboratory, it may be necessary to review pertinent characteristics of nitrate film fires. 1. Once ignited, the combustion proceeds 15 times as fast as an ordinary paper or wood fire. 2. With this speed of combustion, intense pressures are generated by the quickly expanding gases, gauged in tests as up to 18 pounds per square inch. 3. These expanding gases are highly toxic, consisting largely of carbon monoxide and oxides of nitrogen; such as nitric oxide, nitrogen dioxide, and nitrogen tetroxide; from one to nine percent by volume (See Tables on following page) . When these characteristics are considered, the source of ignition becomes relatively unimportant. Whether the fire begins because of spontaneous combustion (not too probable if film is inspected) , accidentally, by laboratory procedures (possible) , or if a fire begins in other material and then involves the film (most probable) , the end result would be the same. A film fire in the laboratory process would quickly involve other materials and film, instantly forcing toxic gases out into the corridors and the exit stairways. Both laboratory employees and the public or other NARS employee in the snack bar could be trapped. A film fire in the "Baltimore" vaults could conceivably relieve or vent hot expanding toxic gases into the film laboratory. A fire in the walk-in cooler, with its lack of ventilation or relief vents, could result in a major explosion. None of this is improbable, considering the speed with which fire proceeded in the Suitland vault fires, and considering the casualities suffered in the Cleveland film fire of 1929. Ref. Appendix C. Item 5.