Boston firefighters battle a 4-alarm fire inside a high-rise construction site

Boston firefighters battled a four-alarm blaze Saturday afternoon inside a high-rise building under construction downtown.

This is the second time a fire has broken out at the construction site, which is part of the Bulfinch Crossing development project.

In a series of tweets, the Boston Fire Department said it was called to 1 Congress St. for a fire report. Once firefighters were on scene, the fire quickly grew to a three-alarm fire.

The department said firefighters had to chase the fire through several floors of the high-rise building as the fire traveled through ducts and shafts.

Shortly before 1 p.m., the department said, a fourth alert was triggered. He said thousands of feet of hose had to be used to bring water to various points in the building where firefighters were trying to put out the fire.

Eventually, according to the department, firefighters had to cut open the walls to reach the fire and use saws to open the ducts.

Around 1:45 p.m., firefighters were still battling the blaze. Two firefighters had also been taken to hospital at the time due to heat exhaustion despite the regular rotation of companies by commanders.

Eventually, around 6:30 p.m., firefighters began to leave the building, the department said. Some companies were forced to rotate and check the building for hot spots they might have missed.

The fire started inside a high-rise building called OneCongress, which is part of the Bulfinch Crossing development project. Once completed, the skyscraper will be used as an office tower.

It is not known what caused the fire or how the fire will affect construction.

The fire is the latest in a series of problems faced by the Bulfinch Crossing project.

In mid-July, seven people were arrested for breaking into the demolition site of the Government Center Garage, which is part of the project. At the end of June, a fire broke out on the 20th floor of OneCongress.

The spring demolition of the garage resulted in the death of Peter Monsini, a 51-year-old construction worker, on March 26, and many problems for the MBTA.

Bulfinch Crossing is a development project by HYM Investment Group.