Red chemical hazard tape surrounded the John W. Harshbarger building, 1133 E. James E. Rogers Way, last night after approximately 100 students were evacuated following a chemical gas leak.

A group of graduate students working in a chemical and environmental engineering lab noticed that argon gas was escaping from a broken tank.

“”The tank started to leak argon gas and the valve was frozen, so we couldn’t close it,”” said Brenda Verdugo, a chemical engineering graduate student.

“”We tried to call the cryogenic facilities who control the tanks, but because it was a little after 5 o’clock, they were closed,”” said Antonia Luna, the research assistant in charge of the lab. “”We then called 911, and I told the students to leave the lab and then the police told us all to evacuate the building,”” Luna said.

The University of Arizona Police Department received the call at 5:21 p.m. and by 5:30 p.m., James E. Rogers Way was lined with at least three Tucson Fire Department fire engines, two paramedic vehicles, two additional TFD vehicles and three UAPD patrol cars.

“”There was no immediate danger, but we were playing it on the safe side,”” said UAPD spokesperson Sgt. Keith Brittain. “”Until we could verify the argon leak and the situation was under control, a fleet was sent out.””

Verdugo said some of the students exposed to the gas breathed in trace amounts before being able to evacuate the building.

“”Argon is not a toxic gas, but it is heavier than oxygen and can thus displace the oxygen in the room,”” said Norm Carlton, TFD public information officer. “”If the argon displaces the oxygen then it can become a common asphyxiate.””

The broken gas tank was removed from the building, Carlton said. Once the air was circulated throughout the building and the argon dissipated, everyone was able to return.

Carlton added that students will be fine for tomorrow’s classes.