What was that noise? It's Con Ed releasing steam on the Upper East Side

UPPER EAST SIDE, Manhattan (WABC) -- Residents on the Upper East Side were concerned when they heard a loud boom, but it was caused by Con Edison.

A steam safety valve caused a loud noise and sent steam billowing out the top of a building on 74th Street and York Avenue.

It happened around 8 p.m. on Tuesday.

Con Ed said that 310 lbs of pressure was released from steam plant that supplies steam system to hundreds of buildings in Manhattan below 96th Street.

The utility said that it was a defective steam valve which then triggered a safety valve/safety system and that is what caused steam and loud noise.

"The safety valve worked the way it was supposed to," Con Ed said.

No one was injured inside or outside of the plant.

Con Edison service was not affected.

Repairs are being completed by workers inside the plant.