The fire broke out at Columbus Chemical Industries' warehouse late Monday, and three explosions rocked the building just after firefighters arrived, Acting Fire Chief Mark Kenevan said. Firefighters withdrew to let the chemical fire burn out.
Resident Kim Buss, 44, said one explosion shook her house about a half block from the plant.
"When it exploded, it was like a black mushroom. Looked like fireworks," she said. "Then we saw all the fire trucks leave."
Authorities said about 140 residents within a half-mile from the plant were evacuated and others were told to stay inside and to keep their windows closed because of the smoke.
By Tuesday morning, more than a dozen firefighters and emergency workers had been taken to a hospital for decontamination.
Officials monitored air quality but had found nothing that exceeded federal air standards, said Steve Quandt, the company's executive vice president.
But resident Jim Neuman, 43, said the air smelled like sulfur and that he, his girlfriend Kim Buss, and her son woke up with sore throats. "We got a blast of something," Neuman said.
Columbus Chemical Industries provides chemicals to high-tech and pharmaceutical companies, among others, according to its Web site.
Records show the plant was cited in 2005 for 10 safety violations, including eight labeled "serious," for issues including handling of flammable and hazardous materials and maintenance of safety equipment. Federal safety officials fined the plant about $4,300.
Occupational Safety & Health Administration spokesman Scott Allen said the company promptly corrected each violation and has had no problems since.
Quandt apologized to the community for the evacuations. "I would like to apologize to all the people we inconvenienced," he said at a Tuesday morning news conference.
No workers were at the plant at the time and it's not clear yet how the fire started, Quandt said.
Columbus is about 25 miles northeast of the state capitol, Madison.
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