1975 New York Telephone exchange fire

At this time, the building contained central offices for connecting local customer telephone lines, as well as toll switching systems.

The events relating to the fire make it notable for reasons including the extent of the disruption and the large scale and speed of the recovery efforts, which were completed in 23 days.

Decades later, the polyvinyl chloride (PVC) combustion products produced by the fire were identified as a reason for elevated rates of cancer in the firefighters at the scene.

[4] The building housed the main distribution frame and contained twelve exchanges and five toll switching machines.

All of this equipment took up enormous space and by the time of the 1975 fire it was interconnected with tons of cable, much of it sheathed in PVC.

He had to use a street call box to alert the fire department, where the first alarm was sounded at 12:25 a.m.[5] Upon arrival, firefighters found the entire building filled with smoke with the heaviest on the lower floors.

[6] Windows were constructed with wire mesh glass and further shielded with plastic or metal screens to protect switching equipment.

[6] The fire cut off telephone service to a 300 block area of Manhattan that included three hospitals, three police stations, two universities and the main headquarters of ConEdison.

[8] The response to the emergency was quick with New York Telephone, parent company AT&T, research division Bell Laboratories and the equipment manufacturing arm Western Electric coordinating the restoration effort.

A main distribution frame normally took six months to manufacture and install but one ready for shipment to another office was located at Western Electric and diverted to New York.

[citation needed] Damaged switching equipment contacts were manually cleaned and millions of individual wires spliced by hand.

The combination of the flammable insulation and the method of penetrating each floor allowed the fire to spread rapidly, and emit toxic fumes that are alleged to have caused later deaths of over a dozen firefighters.

[6][12] Chief of Department James Leonard, whose father worked as a switch operator, said "I've never seen smoke like that, conditions were brutal.