A Dallas high school was evacuated Friday after reports of a strong-smelling gas.
Students and faculty self-evacuated Irma Lerma Rangel High School on the 1700-block of Robert B. Cullum Boulevard and sought refuge at a gymnasium across the street.
Dallas Fire-Rescue and HazMat crews arrived and, using hand-held detectors, determined there were high levels of carbon monoxide, which is odorless, in the school.
Firefighters ventilated the school and the levels of carbon monoxide became undetectable. With the source of the leak undetected, investigators decided to close the school for a couple of hours to see if the carbon monoxide levels became elevated again.
Meanwhile, Atmos Energy was called out to determine if a second leak could have accounted for the smell.
At 1 p.m., DFR returned to the building and detectors measured no trace of carbon monoxide. They also discovered the source of the leak was a boiler that was not venting properly.
The problem was addressed and everyone was allowed back in the building.