1975 New York Telephone Exchange fire

The New York Telephone Exchange fire occurred on February 27, 1975 at the New York Telephone Company switching center at 204 Second Avenue (at Thirteenth Street in lower Manhattan). At this time, the building contained a local exchange (central office) used to connect local customer phone lines. The fire disrupted service for 175,000 customers, connected to the building through 105,000 service loops. Just after midnight on February 27, 1975 a short circuit on the first floor of the building started the fire. Because the cables were insulated by plastic, it spread quickly to the higher levels cutting off nearly all connection to the Bell System Network. As a result, calls to the Fire Department of New York failed because the telephone lines were disconnected.^[1]In an attempt to activate the alarm in the street, a call got through to the fire department at 12:55 A.M. However, the fire was not declared under control until 3:40 A.M. Shortly after that, the fire reignited and was officially declared under control at 4:46 AM. ^[2]This was the worst single service disaster suffered by any single Bell operating company in the 20th century.

The building housed fire destroyed the main distribution frame, which was significant because the building contained twelve exchanges and five toll switching machines. The events relating to the fire make it notable for a number of reasons, including the extent of the disruption, the large scale and speed of the telephone system's recovery efforts (completed in just 23 days),^[3] and its starting or speeding the adoption of fire-safety rules covering the installation of low-voltage wiring inside buildings, especially in areas that can spread fire or toxic fumes.

History

Up until the late 1970s, telephone companies were still using many electromechanical panel switches, which were first implemented during World War I. In order to get their money's worth, the companies used the same infrastructure for forty years. Because of this, many telephone companies left customers without service due to damage to the aged infrastructure. Most recently, Verizon customers in New York City experienced service outages from copper breakdowns. In addition, AT&T customers on the West Coast reported similar outages due to flooding. It was not until the 1970s that Bell decided to "completely scrap their electromechanical switches in favor of newer electronic technology." ^[4] New infrastructure took up a fraction of the space and had a greater capacity than the previous switches. This was critical in the 1970s because the demand for more lines increased rapidly. However, Bell was skeptical and moved carefully to these upgrades and only finished updating the last switches to stored program control in 2001. ^[5]

Health Risks

Due to the chemical toxins that were released during the fire, many firefighters who fought the fire in 1975 later developed cancer. The burning toxins from the PVC insulated wiring that burned has shown heightened risks of cancer years after exposure. Approximately forty cases of cancer can be linked back to the fire. Dr. Steven Lin, a doctor at the Mt. Sinai School of Medicine, investigated the relationship between the toxins and the cancers developed by firefighters. He concluded that polyvinyl chloride, a chemical present during the fire, leads to various types of cancer. However, these cancers are developed twenty years after exposure.

During the fire, the Fire Department of New York did not document the medical records of the firefighters, making it nearly impossible to track their health progress. Instead, they put a red stamp on the firefighters documents that said "Telephone Exchange Fire" to simply show they were there. In 1997, The Fire Department interviewed two hundred and thirty nine fire fighters involved in the fire and found eighteen had died. Seven of these eighteen deaths were from cancer and six of those deaths were from first responders. The average age of those deaths was fifty. Shortly afterwards, The Fire Department of New York created a law that compensated all firefighters who developed cancer after the fire by paying then seventy five percent of their pension. The Fire Department assumed all cancers were a result of the fire. However, if the cancer is diagnosed after retirement, there is no compensation^[6]

Recovery

Many of the first responders to the fire were employees of Bell Companies and Western Electric. Five thousand employees collaborated to restore service. A main distribution frame was ordered and shipped to Manhattan for installation. The main distribution frame typically takes six months to install because its massive framework supports hundreds of miles of wire. Remarkably, it only took them four days to install. Twenty four days later, service was restored entirely. ^[7]

Impact on fire safety and building code regulations

The origin of the fire was sparks from equipment in the basement cable vault igniting the plastic insulation on nearby cables that ran to all of the floors above. The combination of the flammable insulation and the method of penetrating each floor allowed the fire to spread rapidly^[8] and emit toxic fumes that are alleged to have caused later deaths of over a dozen fire fighters.^[9][10]

The resulting fire safety regulations include various codes that relate to Plenum cable:

• NFPA 90A: Standard for the Installation of Air-Conditioning and Ventilating Systems The original restrictions on cable ratings date from 1937, were relaxed in 1975,^[11] and then increased again in
• National Electrical Code (Same as NFPA 70)
  • NEC Article 725
  • NEC Article 760
  • NEC Article 800
• NFPA 255
• NFPA 262
• UL 910
• UL 444

External links

• Avoiding a Dangerous Journey
• Limited-combustible cable makes for safer plenum spaces
• Fire history: New York Telephone Exchange fire

References