At approximately 4:15 PM on April 29, 2025, Chelsea Fire Alarm transmitted a box for a reported building fire on Heard Street. Dispatch advised responding units that they were receiving multiple 911 calls. Engine 2, already nearby on a medical call, reported visible smoke in the distance. Upon arrival, Car 3 confirmed the report and declared a working fire, prompting the response of all Chelsea fire companies and mutual aid. Firefighters located the fire in a one-and-a-half-story garage behind a Heard Street residence, with additional access from Blossom Street. Crews quickly stretched a line and began knocking down heavy exterior fire along the bravo and charlie sides of the structure. Tower 1 was positioned in a nearby driveway to facilitate vertical ventilation from the bucket. At 4:21 PM, Command requested a second alarm, bringing in assistance from Everett, Revere, Boston, Medford, and Massport. The bulk of the fire was knocked down within 15 minutes, though crews remained on scene for over an hour conducting overhaul and checking for possible extension.