A series of explosions rocked a chemical plant in north Fort Worth on Thursday afternoon, unleashing an enormous pillar of black smoke that could be seen 20 miles away.
At least three people were taken to hospitals with non-life-threatening injuries, including one with burns to his hands, officials said.
The cause of the initial explosion at Valley Solvents & Chemicals was not immediately known, but it sent many people in the area running for cover.
"It sounded like and looked like a tornado," said Jeff Maxwell, 53, who was having lunch nearby.
The five-alarm blaze began at 11:30 a.m. PDT and was exacerbated by toxic chemicals igniting inside the building. Firefighters were letting the chemicals burn, officials said.
Among the chemicals involved were methanol, sulfuric acid, hydrochloric acid, phosphoric acid, napthalene and isopropyl alcohol, according to fire officials.
Most of the chemicals on fire are considered to be toxic by the federal government. Napthalene is a known human carcinogen; sulfuric acid, hydrochloric acid and phosphoric acid are lung irritants.
Some of the chemicals were stored in vats holding as many as 4,000 gallons, according to fire officials.
Witnesses across the street from the plant reported hearing an explosion, looked behind them and saw fire and a column of smoke. One man injured himself diving under a tractor-trailer.
Witnesses told firefighters the blaze appeared to have begun in an area where a truck had recently pulled up and started unloading.
Fire officials said they were considering letting the blaze burn out on its own, both because of the amount of water it would take to battle the blaze and because of the concerns with runoff from the site.
About a dozen employees were at the plant when the fire started.