More than 100 firefighters responded to the blaze at the two-story building on the 2800 block of West 7th Street around 4:09 a.m.
There are about 10 businesses in the building. The back portion of the structure was being renovated for apartment use, officials said.
No one was inside the building when the blaze started, but one civilian was treated for smoke inhalation and released at the scene, according to fire officials.
The cause of the fire remains under investigation. Arson investigators were called to the scene.
The flames broke out as firefighters were battling a different blaze at an apartment complex under construction in downtown Los Angeles.
According to investigators, there's no information at this time to indicate that the two fires are related.
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