Police and fire responded to an incident in downtown Lansing near the Biggby Coffee at 115 West Allegan Street at 4:20 Saturday afternoon.
A HAZMAT team and a technical rescue team rushed to the scene. First responders evacuated the area and closed some streets after a piece of the roof fell off the Capitol Hall building.
Firefighters say pieces of the roof hit a gas meter on an adjacent building and caused a gas leak.
"Crews were immediately able to isolate that leak and board off that area," said Steve Babcock of the Lansing Fire Department.
The fire department also checked adjacent buildings for resulting gas leaks.
Witnesses tell a story of a brick thunderstorm.
"A deep bass, some shaking," said Nicholas Ketchum of the incident. He was working in the building next door at the time. "It felt like a truck going by and a rain of bricks and dust and mortar. It was just a lot of debris and a lot of commotion."
The building, standing ten stories tall, was built in 1916, according to the city assessor's web site. It houses offices for several companies.
Building management said the timing couldn't have been better for something like this to happen.
"Often times you'll find people in the alleyway drinking coffee or smoking cigarettes or reading the newspaper right in the spot where it crashed," said Ketchum. "It could have been a problem [during the week] to say the least."
"Had this occurred on a normal work day, it's very possible that result could have been different," he said.
The scene was cleared while crews fixed the leak.
Engineers are investigating why the part of the roof collapsed in the first place.