Two people were killed and four others were critically injured on Thursday afternoon in a reported explosion at a large coal power plant near Tampa, Fla., the authorities said.
Emergency workers responded around 4:20 p.m. to the Big Bend Power Station in Apollo Beach and found six people with severe burns at Unit 2, one of its four coal-fired units. Two people were declared dead at the scene, and the four others were taken to Tampa General Hospital with life-threatening injuries, the authorities said.
The workers, who included one plant employee and five contractors, suffered burns and other injuries, said Corey Dierdorff, a spokesman for Hillsborough County Fire Rescue. “They would be categorized as very severe,” Mr. Dierdorff said at a news conference.
A spokeswoman at Tampa General Hospital said Thursday night that it would not immediately release the conditions of the four patients. Two people were taken there by air ambulance and the other two by ground.
Officials with the Big Bend plant, which is operated by Tampa Electric, said the episode occurred while workers were conducting “routine maintenance” on a slag tank at the bottom of Unit 2’s boiler. The tank collects coal slag, a glass-like waste product formed after the remains of burned coal are mixed with cold water. It is sold and reused as an abrasive in products like sandpaper.
The two workers who died at the plant were covered in slag, which can reach temperatures far above 1,000 degrees, the authorities said.
“We are looking into what happened,” Cherie Jacobs, a Tampa Electric spokeswoman, said in an interview. “There are few details.”
Mr. Dierdorff said about 7 p.m. that the situation was under control and that all other workers had been accounted for. Unit 2 was shut down after the accident.
The Occupational Safety and Health Administration, the federal agency that investigates workplace accidents, did not immediately respond to an email requesting comment on Thursday night.
The agency levied a $25,200 fine in 1999 against Tampa Electric, which is a division of TECO Energy, for serious safety violations at the Gannon Power Station, another plant in Hillsborough County that now operates under a new name. The safety violations led to an explosion that killed three people and injured dozens more. In 2000, the company paid a $7,000 fine by O.S.H.A. in connection to an electrocution and $3,375 for violations related to the housekeeping of coal at Big Bend Power Station.
The Big Bend Power Station sits on about 1,500 acres off a road by the same name on a swath of waterfront land in Hillsborough County, about 15 miles southeast of downtown Tampa. It is among the largest plants in Florida, producing more than 1,700 megawatts of electricity.
The first of its four coal-fired units began service in 1970, according to the company. The second unit, where the accident occurred, went online in 1973. A natural gas and “fuel oil-fired peaking unit” was added eight years ago.
The plant also features a “Manatee Viewing Center” that The Tampa Bay Times said is a popular stop among tourists who can see the station’s towering stacks from almost anywhere in the city.