It was the height of World War II and an immediate question was if the fire was arson or otherwise intentionally set as an act of sabotage. Investigations quickly led to discounting an intentionally set fire, and the following concepts where investigated to address the ignition source and rapid fire spread. Ultimately, while considered accidental in nature, the official cause of the fire as indicated in the Commissioner report from the Boston Fire Department is “unknown.”
Alcohol: Fumes from the breaths of drinkers and from open containers as a cause of the fire was suggested in some area newspapers. Moulton, in his Report of the fire, said “Evaporation from drinks on tables in sufficient quantity to furnish a flammable mixture is not theoretically possible unless the liquor is served straight and warm which is contrary to practice in such places. Ethyl alcohol in 50% concentration by volume, which is about maximum of any ordinary liquor, does not produce flammable vapors except at temperatures above approximately 85 degrees F.
The busboy: Initially, the ignition source was thought to be the bus boy. Stanley Tomaszewski, 16 years of age, in questioning by the police, indicated that he had struck a match to see to try to screw in a light bulb in one of the artificial palm trees in the Melody Lounge. Tomaszewski did not see the fire start. Testimony from witnesses were conflicting--some said the fire started in the palm tree, others said they saw flames breaking out on the cloth covering the ceiling, while it was also reported that the walls had been hot for some time. With unanswered questions on other possible sources of ignition such as the electrical wiring, Tomaszewski was absolved of any guilt by the authorities, but he was always assumed guilty by many of the public.
Ceiling tile adhesive: Post-fire photographs show that there had been ceiling tiles in the new Broadway Lounge. Francis L. Brannigan, a noted fire safety expert, said in a 1991 letter to the NFPA Journal, that there was a history of the fixative for holding up ceiling tiles has been documented as a significant contributing factor of many various disastrous fires. In the past, when renovations were made, the old ceilings were just covered up by new ones, retaining the hazardous properties.
Electrical wiring: Electrical work done in the Melody Lounge three years prior to the fire and to the new Broadway Lounge in the two months prior to the fire, was done by Raymond Bear, a pipefitter who was not licensed as an electrician. Baer was interviewed and admitted that he had performed electrical work in the Cocoanut Grove in October and November of 1942, installing electrical fixtures in the new Broadway Lounge. He also said that there was no permit issued for the electrical contracting.
In the interviews of survivors, Joseph Francis Kelley, a building constructor, testified that he saw a momentary flash of flame. “The smoke was thick and oily.” “The fire preceded the smoke.” To the question did the fire come “along with great rapidity?”, Kelley said “As if blown by a fan.” “A strata of air was under the smoke.” When asked if he could give an opinion as a building construction man as to the cause of the fire, Kelley said: “It could only have been caused by a short circuit under the bar in the Melody Lounge. There was a series of Neon tubing running the length of the bar. In my opinion a short circuit would spread down through and cause the wiring to set up spontaneous combustion. I never saw anything get going so sudden. There was so much smoke. But whatever happened happened awful fast.” He went on to testify, “The flame I saw I know the nature of the composition. It was definitely a gaseous flame and it was completely combusted. It was like an illuminating gas flame. Blue with red tinges. Definitely blue.”
Flame proofing chemicals: Flame proofing materials were suspected as being a source of toxic gases. However, symptoms reported by survivors were not consistent with ammonia fumes from the flame proofing, although today some of the conclusions immediately following the fire are being questioned based on modern forensic techniques.
Nitrocellulose: Before it had been transformed into a nightclub, one of the businesses in the original building was that of a film exchange. Nitrate (nitro-cellulose) film was used for motion pictures and was highly combustible. Some people raised the idea that leftover film from the 1930’s had been stored in the Grove. No evidence of film was found, and a letter from A.S. Dickinson of the Motion Picture Producers & Distributors of America, to the NFPA stated that Paramount had moved out of the building in 1935. He said that it was “inconceivable to conclude that a scrap of film had been left in the exchange and after nearly eight years, suddenly caught on fire …”.
The artificial leather, used in some of the decorations, contains some nitrocellulose in the form of pyroxylin, but the artificial leather used in the club tested too low a percentage of pyroxylin to have been a factor.
Refrigerant gas: Initially, gases used in refrigerating units was discounted on the basis that those gases commonly used were not so flammable as to produce a flash fire such as what was observed. Even though some refrigerant gases are toxic, it would have been too much of a coincidence for the tubing in the units to break down just as the fire started.In recent years, there has been a growing interest in the theory of refrigerant gas as a significant contributing factor with the fire. Jack Deady, Jr. spent most of his life studying the fire, and he confirmed that methyl chloride, not Freon, was the gas used in the refrigerating units at the Cocoanut Grove. This re-introduced the possibility that the gas may have leaked out and was ignited. Deady did noteworthy investigative research on this theory before he died. Two interviews with him in 2007 fully expand on his theory. Deady and Charles Kenney, Jr. collaborated on developing this theory. Deady’s research and papers are in a private collection; Kenney’s papers are at the Boston Public Library.