A chemical spill caused students and University employees to evacuate Lind Hall and the mechanical engineering building about 1:30 p.m. Tuesday. No one was injured.

Greg Hestness, police chief for the University, said a leak started from a tank holding a dangerous chemical, boron trifluoride, in the basement of the mechanical engineering building.

University spokeswoman Patty Mattern said the leak started when a graduate student was working with the chemical.

The student immediately called 911, Mattern said.

Students and faculty members in connected buildings, including Ackerman Hall, were evacuated because the gas could have traveled, said Steve Johnson, deputy police chief for the University.

Johnson said that when the leak occurred, the vents in the room should have taken the gas outside.

Kathy Boyer, an administrator for the Institute of Mathematics, said she was working when police told her to get out.

“They said, ‘It’s a chemical spill and it will travel,’ ” she said.

About 2:30 p.m. fire trucks, ambulances and police cars still blocked Church Street Southeast.

“They’ve got a lot of vehicles here,” Boyer said. “It must be major.”

Adam Ragatz and Chris Morgan, both mechanical engineering seniors working in the Center for Diesel Research, said the alarm went off and they were told to evacuate.

Ragatz said that when he asked when they could go back in the building, they were told it was going to be a while.

Hestness said Lind Hall and the mechanical engineering building were evacuated and the air exchange was stopped between Rapson Hall and Shepherd Labs.

There were no injuries and the fire department did an efficient job making sure the building was safe, Hestness said.