Construction workers working next to Lafferre Hall hit a gas line.

Sixth Street between Elm and Conley was shut down by MUPD.

"The wind, typically when you have decent winds like we did today, it will help dissipate the natural gas," Eric Hartman of the Columbia Fire Department said. "Today what it did though was it helped to push some of that gas into Lafferre Hall."

About 100 people were evacuated from nearby buildings.

"At 11:30 approximately, I smelled gas and I ran downstairs and talked to the building coordinator and he called the fire department and we evacuated the building," said witness Sara Rosenkoetter.

Final exams were being taken at the time of the evacuation and a graduation ceremony that was scheduled at Jesse Hall was delayed as firemen checked for leaks.