At least three people were injured in an apparent explosion Saturday that triggered a major-emergency fire at a single-story commercial building in downtown Los Angeles.

Firefighters were dispatched at 12:05 p.m. to 743 s. Kohler St. and took “defensive firefighting operations” in battling the blaze, said Brian Humphrey of the Los Angeles Fire Department.

The structure was described as a one-story, 50-feet-by-100-feet business in a row of commercial structures, said Humphrey, who added that 137 fire department personnel were at the scene.

The fire sent a black plume of smoke into the sky that was visible for miles.

“We are awaiting an update on (all civilian) patient count and condition,” Humphrey said shortly after 1 p.m.

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