OAKLAND (CBS SF) — Two Oakland commercial buildings — one housing a large marijuana growing operation — were destroyed by separate multi-alarm fires overnight, but aggressive responses by firefighters prevented the flames from spreading to nearby buildings.

A third blaze — a two-alarm fire — also heavily damaged a home at 12th and East 23rd avenues. Overall, Oakland firefighters fielded 61 fire-related calls.

Oakland Fire spokesman Michael Hunt said his agency got 911 calls at around 12:25 a.m. reporting the blaze in a warehouse in the 900 block 77th Ave. Arriving crews quickly elevated it to three alarms as towering flames and smoke roared from the building.

“At this point, that’s what we know, it started as a roof fire,” he said. “But what exactly caused it is not clear at this time.”

Firefighters could not rule out if the blaze was triggered by illegal fireworks use. Illegal fireworks were being set off in the neighborhood at the time of the fire.

The intensity of the blaze forced firefighters to take a defensive approach to the fire and crews spent hours dumping water on the smoldering structure. At the height of the fire there were 40-50 firefighters on the scene.

The building houses two businesses — a marijuana grow and an auto body shop. The three-alarm blaze was under control by 3:37 a.m.

No injuries were reported.

At 2:30 a.m., firefighters responded to 911 calls reporting a fire in a two-story residence at 12th and East 23rd avenues.

The fire started in an attic and flames were coming out of ventilation vents in the roof as firefighters arrived.

One person was treated for smoke inhalation. The cause was under investigation.

At 3:41 a.m., fire crews responded to a 2-alarm fire inside a single-story commercial building at 42nd Street and Telegraph Avenue in the Oakland’s Temescal neighborhood.

Arriving firefighters found the building engulfed in flames, triggering a second alarm. The blaze heavily damaged the building before it was brought under control.

The structure had been the scene of previous fires and was red-tagged in November 2020, fire officials said. The two-alarm fire was under control by 3:22 a.m.