The Tempe Fire Department responded to an alarm panel signaling a leak in the Engineering Resource Center about 6:50 p.m. on Tuesday, Battalion Chief Tom Abbott said.
Seven fire trucks and several other emergency vehicles were dispatched to the Tempe campus building in response to the alarm from a lab being used for an experiment.
An immediate walk-through of the building showed no leaks or spills, Abbott said.
Hazardous Materials Specialist Al Jensen said the alarm continued to sound for more than an hour and a half, though hazardous-materials responders couldn’t locate any problems.
The system indicated that there was a chlorine leak, and the department originally believed it was hydrochloric acid.
In an effort to preserve the experiment and maintain building safety, the departments attempted to contact the professor leading the experiment before turning off all chemical valves connected to the lab.
Responders reported at 8:20 p.m. that the alarm sounded because of a faulty sensor installed last week.
More than 50 people working and studying in the building were evacuated.
Reach the reporter at tessa.muggeridge@asu.edu.
