The incident was first reported at 6:26 p.m.
The explosion was heard as firefighters responded to a fire in a one-story commercial building at 327 E Boyd St., according to LAFD.
The conditions of the injured firefighters are not yet known.
There were several emergency response teams on the scene, including more than 230 firefighters, officials said.
Flames and smoke were still visible on the buildings after 7:30 p.m.
No further details were immediately available as authorities continue to fight the fire.
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