Troy

A city post office and an RPI building were evacuated and blocks of Broadway were closed Thursday after a manhole cover blew out of its place.

The heavy lid popped into the air just before 11 a.m. outside 542 Broadway, closing the street for a time between 4th Street and 5th Avenue, police said.

For a short time, the air smelled of gas, then of an electrical fire, a witness said. No one was injured and, according to National Grid, no power was lost in the area.

The manhole cover blew off after a water main break shorted electrical circuits, Troy Police Capt. John Cooney said. Pressure built up underground, enough to eventually push the lid out and into the street, Cooney said.

Broadway was reopened around 1:30 p.m.

National Grid spokesman Patrick Stella said crews would further inspect the area surrounding the dislodged manhole to figure out precisely how the incident unfolded and why.

Stella said there is no reason to believe Thursday's manhole cover incident is related to others in the city recent years.

In September 2012, a manhole cover popped several blocks away on the 2100 block of Fifth Avenue. No damage or injuries were reported in that incident, which National Grid said was caused by a cable malfunction.

A number of similar incidents occurred in Albany over the past two years.

In April 2008, a wire shorted-out on River Street, leading to an underground explosion that blew manhole covers almost 20 feet in the air and broke more than two dozen windows.

National Grid is in the second year of a five-year, $76 million underground upstate network upgrade.

bfitzgerald@timesunion.com • 518-454-5414 • @BFitzgeraldTU