Just over 24 hours after a fire engulfed 81 apartment units during the middle of the night in Boulder, authorities have accounted for every resident and believe there were no fatalities, according to the City of Boulder.

Authorities worked around the clock since the fire was extinguished to locate every resident in the 81 units impacted by the fire. Before noon on Wednesday, officials reached every one of them, which was a surprise, said Boulder Fire Rescue Chief Michael Calderazzo.

“I am surprised and relieved to be able to say that it appears we had no deaths,” Calderazzo said.

Prior to the announcement by the city and fire personnel, officials searched through rubble, made calls and explored other avenues to verify residents were accounted for, officials said.

Officials were dispatched to the complex at 2301 Pearl St. around 3:30 a.m. after reports of a structure fire. 12 Boulder officers were among the first on-scene and ran into the burning building to alert and assist dozens of residents out of the building, according to the city.

City officials said the officers reached more than 60 units, while the remaining 21 were unreachable due to the intensity of the smoke and flames.

“Recognizing the danger of the intense, rapidly spreading fire, and without hesitation, our officers ran into the building. They encountered heavy smoke, flames and terrified residents,” said Steve Redfearn, deputy police chief for the Boulder Police Department. “If not for such quick and heroic actions by the officers and our partners, many lives would have likely been lost.”

Members of the University of Colorado Boulder Police Department and Boulder County Sheriff’s Office also assisted in the call, officials said.

An undisclosed number of residents are receiving assistance and temporary housing through the American Red Cross of the Mile High Area. Anyone wishing to assist the victims can donate directly to the Red Cross online or by calling 1-800-435-7669.