OAKLAND (CBS SF) — Firefighters quickly gained control of a blaze racing through a homeless encampment Friday night outside the Webster Tube — the third major fire in an encampment in Oakland this week.

Fortunately, no one was injured in the blaze — which was reported at 10 p.m. — but officials warn the unsafe conditions at the growing, debris-filled encampments may be a disaster waiting to happen.

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“The Fire Department is extremely concerned by the growing number of encampment related fires in Oakland,” OFD spokesman Michael Hunt said. “The conditions inside the homeless encampments are unsafe, and pose a range of health and safety risks first and foremost to the unhoused people living there, but also to the surrounding area, the service providers, and the first responders who respond to incidents at these locations.”

On Wednesday morning, firefighters battled an encampment fire at Wood Street & 18th Street. Multiple makeshift living quarters were damage or destroyed, but there were no major injuries.

The largest fire of the week erupted among recreational vehicles parked in an encampment early Tuesday, sending a massive smoke plume over the city and the nearby 880 freeway.

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Oakland firefighters said the blaze broke out at around 6:30 a.m. at large homeless encampment along East 12th Ave. and 17th St. near the busy freeway. At least two RVs were engulfed and more than a dozen makeshift housing structures were threatened or damaged by the flames.

The flames and smoke were visible to motorists on 880 and slowed the morning commute.

About 20 individuals living in the makeshift encampment were impacted by the fire, but there were no reports of injuries.

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It took about 30 minutes for the fire crews to knock down the flames by at 6:56 a.m.