Waltham Fire responds to elevated carbon monoxide levels at Garden Circle

Fire crews responded to 70 Garden Circle around 8:30 p.m. Thursday after a fire alarm was activated.

Upon arrival, firefighters detected elevated carbon monoxide levels of about 105 parts per million. Crews traced the source to the building’s basement, where a grill was found, according to radio transmissions.

Additional companies were called to assist with evacuations as crews ventilated the building. National Grid was also requested to respond as a precaution.

No injuries were reported.