by North Forty News Staff | NorthFortyNews.com

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Investigation finds outdoor AC work sparked apartment blaze in west Fort Collins

The Poudre Fire Authority has completed its investigation into the apartment complex fire that broke out Thursday, Dec. 11, 2025, in west Fort Collins, determining the blaze was caused by soldering work on an air-conditioning unit outside the building.

According to Poudre Fire Authority officials, a spark from soldering on a ground-floor air conditioner ignited a nearby juniper bush. Flames then spread to the exterior of the two-story apartment complex in the 1200 block of West Prospect Road, traveling up the side of the building and into the attic. Fires in attic spaces can be especially challenging in multi-family buildings because the spaces often connect multiple units.

This fire update follows our earlier coverage of the incident at https://northfortynews.com/category/news/neighbors-help-evacuate-as-fort-collins-apartment-attic-fire-spreads/, where neighbors helped evacuate residents as firefighters responded.

The Fort Collins 911 Dispatch Center received multiple calls reporting the fire, and crews were dispatched at 4:46 p.m., arriving on scene within four minutes. Battalion Chief 1 was the first to arrive and reported active fire on the first and second stories of the complex.

Rescue 4 crews conducted a complete 360-degree assessment of the building while Engine 4 deployed a hose line to begin fire suppression. Residents who were home at the time were able to evacuate independently, and no injuries were reported.

Four apartment units sustained damage in the fire. The last Poudre Fire Authority unit cleared the scene at approximately 7:40 p.m. Officials also acknowledged the assistance of Fort Collins Police Services and UCHealth during the response.

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Source: Poudre Fire Authority