There were no injuries, authorities said.
The explosions at Airgas South Inc. happened as workers were unloading tanks, including flammable acetylene gas, from a flatbed truck. One of the canisters fell and its cap came off, releasing vapors which ignited, Miami-Dade Fire Rescue spokesman Luis Fernandez said.
Company spokesman Jim Ely said the plant distributes flammable gases used in welding.
``The whole ground started shaking,'' said Rick Robitaille, owner of a clothing-decoration company several blocks away. ``We didn't know what was happening. I thought it was a terrorist attack.''
An area within a half-mile of the plant was evacuated, Fernandez said.
As a precaution, students at John I. Smith Elementary School were not being taken outside to their playground, said teacher Mara Hernandez. The school, with about 1,300 students, is some 15 blocks from the site of the explosion.
The Doral Golf Resort & Spa west of downtown Miami evacuated the golf course within minutes as a precaution, resort spokeswoman Carol Murphy said.
Airgas South is a subsidiary of Airgas Inc. of Radnor, Pa., which had several explosions at other plants last year in California and Oklahoma. No one was hurt in those blasts.
Ely said those blasts were accidents. ``We actually have a very strong safety record,'' he said.
