Minneapolis fire crews responded Wednesday to a carbon dioxide leak that forced the evacuation of students and staff members at the Bell Museum of Natural History.

About 11:15 a.m., four fire trucks arrived at the museum as police cars blocked off surrounding roads. Firefighters evacuated the museum and stopped the leak, said 3rd District Battalion Chief Todd White.

Firefighters donned air packs and used special equipment to stop the leak, said Alison Falldin, a visitor service specialist for the museum.

“There was a haze and mist in the air,” she said.

Fans might be used to help ventilate the building, Falldin said.

The museum has a system located in a secure storage room in the basement that releases carbon dioxide to remove oxygen from the air.

The system helps preserve artwork in the building, said University Police Sgt. Brad Herberg.

Three out of four tanks leaked carbon dioxide, said Brad Hoff, Facilities Management’s communications director. There was no fire and officials are investigating why the leak occurred, he said.

Herberg said that though he doesn’t know how dangerous the gas was, “you don’t really want to breathe it.”

An organic chemistry test interrupted by the leak was not canceled, said Youa Xiong, a biology junior. The test was moved to Nicholson Hall.

A leak like this has never happened at the museum, Falldin said, adding the building has 30-year-old pipes.

Nina Shepherd, Bell Museum public relations director, said the museum is hoped to move to the St. Paul campus by 2010.

“The current building, which opened in 1940, really falls short of what visitors expect from a contemporary museum,” she said.

Shepherd said the museum does not have a large lobby, large galleries, open reception areas or air conditioning.

“It seriously limits what we can do,” she said.