A fire of incendiary origin occurred at the Ozark Hotel in Seattle, Washington, on March 20, 1970 and claimed the lives of 20 occupants. Fire investigators determined that a flammable liquid had been poured and ignited on the first-floor level of two open stairways. The fire quickly spread throughout the building rendering the stairways and corridors useless. As a result, 20 occupants perished, either from smoke inhalation or from injuries suffered when jumped from the upper stories.
NFPA members can download the Fire Journal  article January 1971 Fire Journal article
Those interested in more information about hotel and motel fires can downloadNFPA's Hotel and Motel Structure Fires report and fact shee
t More information on intentional fires NFPA's report on Intentional Fires