Natural gas leaks — similar to the one thought to have caused an explosion earlier this month in East Harlem that leveled two buildings and killed eight people — are commonplace, according to federal records.

More than half of the 9,906 leaks in New York City and Westchester County reported to suppliers Con Edison and National Grid in 2012 could have harmed people or property, an analysis of federal data from the Department of Transportation showed.

The danger largely stems from the city’s aging network of gas mains made of leak-prone cast iron, wrought iron or unprotected steel, the New York Times reported.

Replacing the 6,302 miles of pipes won’t be cheap or easy — it could cost upwards of $10 billion, the article said. In traffic-heavy areas like Manhattan, installing new mains would likely cost up to $10 million a mile, according to Con Edison officials. Even if the funds are made available, replacing “vintage” pipes will take as long as 25 years, according to National Grid.

“Accelerated replacement is not the answer to today’s problem; it’s the answer to tomorrow’s problem,” Mark McDonald, who investigates gas explosions for insurance companies and landlords, told the Times. “What needs to be happening is increased vigilance, increased leak surveys to spot these problems before it gets into someone’s house.”

http://therealdeal.com/blog/2014/03/24/gas-leaks-put-nyc-in-perpetual-danger/