The explosions began shortly before 11 p.m. ET and were felt and heard by residents from miles away.
At least seven people were injured in the explosions.
Fifteen workers were reported missing in the incident but all were later accounted for, a sheriff's official said.
There is "no indication whatsoever" how the fire or explosions started, he said.
Video showed a series of fiery blasts continuing long after the initial explosion.
The plant was said to hold 53,000 20-pound propane cylinders on Monday, many of which were seen in flames on live TV.
Fire officials eventually got a handle on the blaze by early Tuesday morning, but nearby residents were shaken up.
Residents described sounds similar to a shotgun or fireworks and saw bursts of light and a bright orange glow above the treetops, they said. Some reported a "giant fireball" in the sky.
The sight of flames was reported more than five miles away. The vibrations could be felt as far away as Mount Dora.
Jon Passantino is a deputy news director for BuzzFeed News and is based in Los Angeles.
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