On the morning of May 15, 1929, a room in the basement of the Cleveland Clinic began to smoke. Until the year before, it had been the coal vault. About 123 people died. Almost none of them burned. The building was four stories of brick and reinforced concrete, advertised as fireproof. It kept its X-ray negatives in two places, and that is the whole story. Current film sat on the first floor behind an approved fire door, exactly what the regulations asked for. The old film went in the basement, into the room the coal had come out of. Brick, windowless, and with no vent to the outside air of any kind. Wooden shelving packed solid with negatives stacked on edge, a high-pressure steam main running to within seven and a half inches of the nearest shelf, bare light bulbs on cords. And a pipe tunnel that circuited the basement and carried pipes up into every floor of the building, opening directly into the corner of the room. Nobody could say how much film was down there. The engineers who surveyed it afterward put it at about 70,000 sheets, and wrote the sentence that explains the whole disaster. The number of films in the room was unknown, even to the X-ray department employees. Here is the fact almost every retelling of this story leaves out. Burned in the open air, nitrate film is not poisonous. The man who wrote the storage rules for this exact material established it: burn it freely in an excess of air and what comes off is carbon dioxide, nitrogen and water vapour. It is a severe fire. It is not a gas attack. The poison is what happens when the film cannot get air. Starved, it breaks down instead of burning, and what comes off is carbon monoxide and the oxides of nitrogen. The Clinic did not store a poison in its basement. It stored a fire hazard, and then built the one container that turns a fire hazard into a poison. That container had been against the rules for four years. Since 1925 the standard had named hospitals specifically: a vented room, sprinklers, a working fire door, film kept away from heat. The basement room failed every one. At about nine that morning a steamfitter was called down because the line running through the film room was leaking. He stripped fourteen inches of insulation off it, had the line drained, and went back to his shop to let the pipe cool, leaving a bare steam main seven and a half inches from two tons of nitrate film, in a brick room with no ventilation. At about eleven he came back. The room was full of smoke, a yellowish cloud about five feet square, hanging in the corner near the ceiling. Then the gas found the tunnel. It did not seep under doors. It went up inside the walls and out through the openings cut for the plumbing, and in room after room it arrived from the hole behind the washbasin. Out on the street, a man named Joseph Stanley watched a four-story building full of people struggling at the windows, and not one of them calling for help. It was the silence, he said, that was the horrible feature. He did not understand it until he smelled the fumes. The part that stays with you is what came afterward. What killed the ones who died later was nitrogen dioxide, and it could because it does not hurt on the way in. Chlorine and ammonia dissolve in water and scald the throat at once, driving people out into the air. Nitrogen dioxide does not. The victim keeps breathing it, and it reaches the smallest passages of the lungs before it does anything at all. Six years earlier, X-ray film stored in the basement of Boston City Hospital was ignited, presumably by an electric light bulb. A hospital. A basement. Stored X-ray film. A light bulb. Patients on the floors above. That basement had sprinklers in it. The sprinklers put the fire out. Nobody died.
