Three blocks of Nevada Avenue reopened Wednesday night after being closed for nearly five hours because of a chemical spill at Colorado College in Colorado Springs.
Authorities said the incident happened around 3 p.m. in a basement laboratory of Olin Hall, one of several science buildings on campus. About 50 people were in the building at the time, authorities said. Students were taking part in a fire drill when the alarm for the spill was issued.
The chemical is believed to be titanium tetrachloride, authorities said -- a common lab chemical that is corrosive, reactive and releases strong fumes that can affect breathing.
The fire department and a college spokesperson agreed the spill was an accident.
"(The chemical) was taken down to the custodian who was assisting a teacher in opening up one of two bottles in a container, and then that's where it spilled down in the basement," said fire department Lt. Stacy Billapando. "Most of our victims inhaled fumes more than actually getting the chemical on them."
Authorities said 13 unidentified people were overcome by fumes, and two of whom needed help getting out of the building. The victims took off their clothes or were sprayed at the scene for decontamination, then were treated and released from a hospital.
According to a Colorado College release, one victim -- a campus employee whose name wasn't released -- remained in a hospital, listed in serious but stable condition. Billapando said that employee may need further treatment at a Denver hospital.
Students Talisa Sobieski and Sara Robbins were in their human anatomy class in the building when they heard the alarm.
"It was pretty hazy in there," they said. "We were working on cadavers with formaldehyde, and at first we weren't sure if anything was wrong. Then we smelled (tetrachloride). Having a fire drill every month helped us stay calm during this. If this had happened in the morning when more students are here, it would have been a panic."
Authorities closed Nevada Avenue between Cache La Poudre and Uintah Streets. Hazmat crews entered the building wearing protective clothing and breathing equipment, and used electronic monitors to check levels of chemical exposure.
The fire department praised campus staff for starting to evacuate people before hazmat crews arrived.
"(Staff) did exactly what they were supposed to do," said Billapando.
Crews cleaned the spill, contained the chemical canister involved, and reopened Nevada around 8 p.m.
The campus release announced that Olin Hall and the adjacent Barnes Science Center will reopen for classes on Thursday.