BRIDGEPORT — The roof of a building that had been vacant for 20 years collapsed Thursday evening because of heavy, wet snow.

The snowstorm that slammed the region Wednesday dropped about 6 inches of heavy, wet snow on the city.

The building — the old site of the Kay’s Department Store — is located near the intersection of Middle and Golden Hill streets in downtown, across the street from the U.S. Post Office on Middle Street.

Police and fire units initially responded for a building that looked like it might collapse around 6:20 p.m. By 8:15 p.m., the roof and one wall collapsed.

When the roof collapsed, it brought down the side wall facing Middle Street as well, police spokesman Av Harris said. As a precaution, police shut down Middle Street between Fairfield Avenue and Golden Hill Street and Golden Hill Street between Water and Middle Streets.

There was no imminent danger of a total collapse Thursday evening, Harris said. No one was injured by the collapse.

The Post Office will be open during normal operating hours Friday, but will only use the south entrance on Middle Street.

Fire and building departments will assess the situation further Friday morning.