Charleston firefighters are working to determine what sparked a blaze that damaged one of the city's historic buildings along Broad Street.

Witnesses Friday morning reported seeing heavy smoke seep from 67 Broad St., east of Charleston's City Hall and Judicial Center.

Charleston firefighters were dispatched at 7:54 a.m., with the first units arriving within 3 minutes after the initial dispatch, according to Ryan Kunitzer with the Fire Marshal Division. The fire was brought under control within eight minutes of firefighters' arrival.

Daniel Ravenel Jr., 29, said he woke to the sound of fire engines and his father's cries alerting him to the fire across the street from their home.

Flames licked at the far left window of the building's third floor as firefighters approached, Ravenel said. Firefighters broke the window to gain access to the blaze.

"That's when the flames really erupted," Ravenel said.

Crews remained at the site for hours afterward, treating hot spots and surveying the damage. Crowds gathered along the street, taking pictures and watching from a distance while dozens of firefighters worked the scene.

"The rapid response and coordinated actions of the Fire Department minimized the damage to this structure while confining the fire to one building," said Fire Marshal Mike Julazadeh.

Kunitzer said that the building's brick exterior helped prevent the flames from reaching neighboring structures. The fire was contained to the building's third floor and converted fourth-floor attic space, with the lower floors suffering smoke and water damage, he said. There was no word Friday regarding a possible cause for the blaze, which originated within the floor joist area of the third floor.

The building was undergoing renovations before the fire occurred.

Kunitzer reported that residents in the area noted an odor and smoky haze as early as 5 a.m. but couldn't find where it was coming from. He urges people to report any unusual odors or visible smoke by calling 911 so responders can be sent to investigate.

The three-and-a-half story building, with a passage through the west side, was constructed between 1758 and 1765 by John Hume, a prominent merchant of the period, according to a building inventory at the Charleston County Public Library. In the 19th century, it was the annex of the famous Jones' or Mansion House Hotel, located next door to the west, the inventory stated.

The 5,358-square-foot building, owned by Broad Street LLC, is listed for rent online. The company bought the building from Cobblestone Associates in February for $2.7 million, according to Charleston County records.