BROOKLINE — An underground explosion caused by a gas leak popped off four manhole covers and damaged some buildings on a stretch of Route 9 Wednesday night, a fire official said.
“Something ignited it, possibly electricity, but we’re not 100 percent sure of that yet,” Deputy Fire Chief Patrick Canney said at the scene shortly before 9 p.m.
There were no injuries and no cars were damaged, he said.
The explosions, which occurred at about 6 p.m., broke some glass in buildings along Boylston Street, which is Route 9, and three or four businesses were evacuated, he said.
Any residents who left their homes because of the incident were cleared to return by 8:30 p.m.
Firefighters were investigating possible carbon monoxide in the basements of some of the buildings Wednesday night, he said.
About 25 firefighters responded to the scene which caused Route 9 to be closed in both directions for a time.
But shortly before 8:30 p.m., the eastbound side was reopened to traffic,said Jacquelyn Goddard, a spokeswoman for the state transportation department.
One westbound lane was open between Boylston and Sumter streets, a Brookline police dispatcher said just before 10:30 p.m.
Utility crews from both Eversource, which supplies electricity to town, and National Grid, the natural gas supplier, also responded.
At the intersection of Cypress and Boylston streets, National Grid crews could be seen sticking instruments into two open manholes.
Nearby, police directed traffic off of Route 9. Farther up the thoroughfare, two fire engines sat parked, their lights blinking.
Another National Grid crew toiled farther up Route 9, near the Brookline Driving School.
The sound of loud, sudden booms rattled business owners and employees along Boylston Street.
Rod Rosales, owner of Sizerun Supply, said the first explosion sounded like someone was banging on the window of his shop at 355 Boylston St.
With the windows shaking, he rushed outside, where he saw a second manhole “flipping like a penny in the air,” he said.
Josh Nissenbaum, who works in the shop, ran outside with Rosales. As they walked down the street, they heard a “loud cannon sound” and saw “a manhole fly up,” said Nissenbaum, 17.
Rosales said he saw smoke coming out of both manholes.
“We just freaked out,” said Rosales, 42.“I’ve never seen anything like that happen before other than movies or special effects things.”
Chris Ramusiewicz, a 30-year-old guitar teacher at G4 Guitar Schools, said the explosion sounded like a car had hit the building he works in at 146 Cypress St.
“It was like two huge loud sounds shook the windows,” Ramusiewicz said. “It vibrated the whole place, each [explosion].”
Ramusiewicz said he was unnerved by the explosions.
“They seem to have a handle on it, hopefully, ” he said of firefighters and utility crews on the scene. “So, I don’t think I’m going to be caught by a stray manhole cover just walking home,” Ramusiewicz said. “But I’ll definitely be keeping my eyes out.”