Transformer explodes, fire rages, Back Bay goes dark

At 9:13, Boston EMS tweeted the scene was clear of smoke.

An explosion in a building housing two large transformers next to the Back Bay Hilton's parking garage at 40 Dalton St. sparked a three-alarm fire that filled the area with toxic black smoke just a block from the earlier fire at TC's Lounge, forced the evacuation of a large hotel and caused power outages throughout the Back Bay and surrounding neighborhoods.

Julie Loncich reports 20,000 NStar customers lost power in the Back Bay, the South End, Chinatown and Kenmore Square - and that they could be without power through Wednesday.

Fire at 7 p.m. Photo by BFD:

The fire quickly went to two alarms after firefighters arrived around 6:20 p.m. At 7 p.m., with NStar emergency crews still not on scene despite increasingly anxious requests from BFD, fire commanders declared a third alarm as a 115,000-volt transformer burned, spewing smoke that MBTA officials warned their police officers would not be filtered by their emergency masks. City officials warned people to stay away from the area and stay inside.

Later, the fire department reported:

The transformer that was on fire is cooled with mineral oil. While not toxic, it is never good to inhale any kind of smoke.

Eerie photo down Newbury Street.

Boston firefighters got some help from Massport, which sent two trucks over from Logan, one loaded with the foam needed to put out the oil fire.

Around the area, people reported power issues. Lights flickered and then died from Dalton Street down Boylston around 7:30 as NStar turned off the transformers to help damp the fire.

The Pru, the Hancock and the Hynes lost power; firefighters not at the fire scene went from building to building in the Back Bay, making sure nobody was stuck in elevators. The Fire Department's own fire-alarm office lost power, as Kenmore Square and Columbus Avenue down to West Newton.

Boylston Street isn't supposed to be this dark at night. Photo by Matt Karolian:

View from East Cambridge. Photo by David Cole:

BPD brought in officers from other parts of the city to patrol the blackout area.

The T shut stations at Mass. Ave. on the Orange Line and Hynes, Symphony and Arlington on the Green Line. Firefighters evacuated the Hilton, where guests are expected to spend the night at the Sheraton.

Amy Deveau, out for drinks at the nearby Dillon's, reported firefighters ordered people at the bar to stay inside because of the thick smoke.

Bar-goers were evacuated on a T bus around 8:30 p.m. Riggs, also on an evacuation bus, reports things did not go well:

Bus finally moving from Apple Store to Symphony. Was forced on, then sat 30 mins. Coulda walked out in that time. Bus drove from Apple Store on Boylston to fountain at Church Park. Boston fails at emergencies.

The state shut the turnpike at both ends of the Pru, leading to scenes like this (photo by Gustavo Quiroga):