A chemical explosion injured two graduate students and prompted the evacuation of Amundson Hall on Tuesday morning.

Hundreds of students, faculty and staff were forced to abandon their experiments, lectures and personal belongings at approximately 10:20 a.m. after a chemical explosion in Room 382.

“It was not a huge explosion,” said Director of Emergency Management Judson Freed. “A lot of people were inconvenienced for a while.”

Graduate student Eric Cochran was burned severely when a small beaker full of tetrahydrofuran caused a minor flash explosion.

Tetrahydrofuran is an extremely flammable liquid that burns skin on contact and reacts violently with air when standing, according to chemical safety Web sites.

Cochran and graduate student Thomas Epps, who sustained minor injuries during the explosion, were heating the solvent in combination with another chemical, University officials said.

Epps and Cochran are Ph.D. candidates and graduate fellows in the chemical engineering and materials science department. They were unavailable for comment Tuesday.

The two students walked to Boynton Health Service. Cochran was later transported to the Hennepin County Medical Center’s burn unit. He was in fair condition by 4 p.m.

The explosion was fully contained under the fume hood of the students’ workspace and fire sprinklers were activated immediately.

But one sprinkler, located above the hood where the beaker exploded, continued dousing the area causing extreme water damage to the building’s west wing.

“Most of the damage was done by the water, which was designed to do exactly what it did,” Freed said.

More than a thousand gallons of water produced several inches of standing water on the building’s third floor, causing computer damage and ceiling tiles of lower floors to fall, Freed said.

He was unable to estimate the cost of the damage.

University officials said the east wing will open Wednesday but did not know when the west wing would reopen.

Students may check online at www.classroom.umn.edu for classroom reassignments.

An anonymous 911 caller phoned state police about the explosion on a cell phone.

Minneapolis fire, University police, medical response and hazardous materials units were told there was a chemical explosion, fire and multiple injuries in the chemical engineering building, prompting a massive emergency response.

“It could have been worse, and that’s why we responded as such,” said Kristi Rollwagen, Minneapolis Fire Department spokeswoman.

Amundson Hall was lined with crime tape and Washington Avenue was blocked off between Union and Church streets for approximately one hour.

“We were right in the middle of collecting all our data, so it’s going to screw everything up,” said Brian Kromer, a chemical engineering student.

It is unclear how many chemical accidents or building evacuations there have been at the University, but Freed said they have happened before.