Steam Pipe Explosions

Yes, just the other day I was wondering what's behind (in the case, below) those hundreds of steam pipes in NY, and so I just heard about it: theres really an underground world goin' on there, and for sure sometimes bad things happens, take a look:
(I have the feeling everyone knows about that except me)
http://www.nytimes.com/2007/07/19/nyregion/19explode.html?hp

"A steam pipe explosion beneath a street near Grand Central Terminal yesterday propelled a giant scalding jet of brownish steam toward the sky, sending commuters who had been heading home stampeding to safety.(...)

(all photos by NYtimes)



"(...)The blast, near 41st Street and Lexington Avenue, raised fears of terrorism, but officials were quick to dismiss that possibility. “There is no reason to believe this is anything other than a failure of our infrastructure,” Mayor Michael R. Bloomberg said."

according to http://en.wikipedia.org/wiki/2007_New_York_City_steam_explosion

"(...)More than 12 similar Con Edison steam pipe explosions have occurred in New York City since 1987. One of the most significant events occurred near Gramercy Park in 1989, killing two Con Edison workers and one bystander, and causing damage of several million U.S. dollars. The utility eventually pleaded guilty to lying about asbestos contamination from that accident, and paid a $2 million fine.
A steam pipe explosion at Washington Square in 2000 near the New York University Bobst Library left a 15 foot (3.5 meter) crater in the pavement on Washington Square South, scattering debris and leaving traces of asbestos in the air. The New York Steam Company began providing service in lower Manhattan in 1882.
Today, Con Edison operates the New York City steam system, the largest commercial steam system in the world, with more than 100 miles of steam pipe. It provides steam service to nearly 2,000 customers serving more than 100,000 commercial and residential establishments in Manhattan south of 96th Street. The utility reported that in 2007, the average age of the steam pipes was 54 years, but some were near 100 years old."

Well, as I was there, I though could grab some more information about the steam pipes, which follows:
http://en.wikipedia.org/wiki/New_York_steam_system

"The New York City steam system is a district heating system which carries steam from central power stations under the streets of Manhattan to heat, cool, or supply power to high rise buildings and businesses. Some New York businesses and facilities also use the steam for cleaning and disinfection.

The New York Steam Company began providing service in lower Manhattan in 1882. Today, Consolidated Edison operates the largest commercial steam system in the world, now known as Con Edison Steam Operations, providing steam service to nearly 2,000 customers and serving more than 100,000 commercial and residential establishments in Manhattan from the Battery at the southern tip of Manhattan to 96th Street uptown. Roughly 30 billion pounds (14 million tonnes) of steam flow through the system every year.

Clouds of condensation can sometimes be seen rising from manholes in Manhattan, although this is usually caused by external water being boiled by contact with the steam pipes, rather than leaks in the steam system itself.(...)"