BOSTON -- The snow turned dangerous in Boston's Brighton neighborhood Sunday night when the roof of a pharmacy collapsed under the weight of heavy snow.

NewsCenter 5's Gail Huff reported that police were on hand all night to help safeguard the building and prevent looting at the Market and Surrey streets store near Brighton Center.

Engineers will decide Monday whether any portion of the building can be saved.

The roof caved in about 5 p.m. Sunday. Four employees and a customer were able to get out safely. The customer was hit in the head with some ceiling tiles or debris, but was expected to be OK.

Fire officials blamed the buildup of rain-soaked snow on a flat roof for the collapse.

"There's a big air-conditioning unit right in the middle of the roof which, the weight of the water and the snow combined to cave it in. It's a truss roof which is a flat roof. Lot of weight on a roof during weather like this," Deputy Fire Chief Steve Dunbar said.

"I saw the exterior wall start to buckle and then everything was like a domino coming down," witness Peter Diabiasie said.

One rescuer said the building would likely have to be demolished because the walls are buckling.

In Worcester, a canopy over gas pumps at the Extra Mart Gas Station on West Boylston Street collapsed under the weight of the snow on Monday afternoon. Coincidentally, the gas station was closed at the time of the collapse so repairs could be made to the canopy. No one was injured.

The Massachusetts Emergency Management Agency issued a roof collapse alert. They said flat roofs should be cleared off if they're safe to stand on. They suggested snow rakes for slanted roofs and icicles overhanging doorways and walkways should be removed. Home and business owners were advised to clear drains, whether on the roof or on the ground, to minimize ponding and flooding.