San Francisco firefighters responded to a one-alarm structure fire Sunday afternoon in a three-story abandoned building on Treasure Island. The fire, located at Fourth Avenue and Avenue H, was contained without injuries, and the cause remains under investigation.

San Francisco Firefighters Battle One-Alarm Blaze in Abandoned Treasure Island Building

San Francisco, CA — July 13, 2025

San Francisco firefighters responded Sunday afternoon to a one-alarm structure fire that broke out in an abandoned building on Treasure Island, sending plumes of smoke into the sky and prompting a coordinated emergency response from across the Bay Area.

The fire was reported shortly after 1:00 p.m. at a vacant three-story structure located near the intersection of Fourth Avenue and Avenue H, part of a long-neglected area of Treasure Island that has been undergoing intermittent redevelopment.

According to the San Francisco Fire Department (SFFD), no injuries have been reported at this time, and the blaze has not spread to adjacent buildings. However, firefighters are still working to fully contain and extinguish the flames as of late Sunday afternoon.

Fast Response Prevents Spread

SFFD officials said crews arrived within minutes of receiving multiple 911 calls reporting smoke and visible flames coming from the upper floors of the abandoned building. Upon arrival, responders encountered heavy smoke and fire conditions on the second and third floors.

“Our crews mounted an aggressive interior attack and were able to prevent the fire from extending to nearby structures,” said SFFD spokesperson Lt. Brandon Ellis. “Given the state of the building — abandoned and unsecured — it posed significant risks, including the potential for structural collapse and hazardous materials.”

Firefighters used ladder trucks and hose lines to gain access to the upper levels of the building, while ventilation teams worked to clear smoke from the area. Aerial footage from local news helicopters showed flames licking through broken windows and charred portions of the rooftop as crews battled the blaze.

Cause Under Investigation

The exact cause of the fire is currently unknown. Fire investigators were on the scene Sunday afternoon collecting evidence and interviewing witnesses. Due to the abandoned nature of the building, officials are not ruling out the possibility of squatters or unauthorized entry contributing to the fire’s origin.

“We’ve had repeated issues with trespassing in these older buildings on Treasure Island,” said Lt. Ellis. “That’s part of what makes these calls so dangerous. You never know what or who may be inside.”

Neighbors and construction workers nearby reported seeing individuals entering the building in the days leading up to the fire, but those accounts have not yet been confirmed by authorities.

Abandoned Structures Pose Risks

The building where the fire occurred is one of many structures on Treasure Island that have sat empty for years as part of the slow-moving transition from military installation to mixed-use development. While some areas of the island have been revitalized with new housing and public spaces, many older buildings remain boarded up and vulnerable to fire, vandalism, or unauthorized occupation.

“This is unfortunately not the first time we’ve responded to a fire in an abandoned structure out here,” said one firefighter at the scene who asked not to be named. “They’re a real hazard — especially during the dry summer months when things can spread quickly.”

City officials have previously cited concerns about fire safety, illegal dumping, and break-ins on Treasure Island, particularly in the more isolated pockets of the former naval base. Redevelopment plans are underway, but many projects have faced delays due to funding challenges, environmental reviews, and ongoing cleanup operations related to past military use.

No Evacuations Ordered

Fortunately, the fire did not immediately threaten residential or commercial buildings, and no evacuations were ordered. However, traffic in and out of Treasure Island was restricted throughout the afternoon, with access limited primarily to emergency vehicles.

Residents in newer housing developments further south on the island reported a strong smell of smoke and visible ash in the air, but no property damage has been reported in those areas.

The San Francisco Department of Emergency Management issued an advisory encouraging residents to close windows and doors and remain indoors if sensitive to smoke or air quality.

Cleanup and Monitoring Continue

As of 5:00 p.m., the fire was largely contained, though crews remained on site to monitor for hotspots and assess structural stability. A full inspection of the building is expected to take place once the scene is deemed safe.

Fire officials say the building will likely be deemed a total loss and are urging the city to expedite its demolition to prevent further risk.

“This is a wake-up call,” said Lt. Ellis. “These abandoned buildings are more than eyesores — they’re dangerous. We need to prioritize securing and clearing them before someone gets seriously hurt.”

This is a developing story. Updates will be provided as more information becomes available.