Eight workers were injured late Monday night, including four critically, in a series explosions that could be heard from up to 10 miles away inside a central Florida propane plant.
Authorities have not ruled out human error and say it appears workers were on the assembly line when the fire broke out.
One person was listed in critical condition at the University of Florida Health Shands Hospital. Three other workers were transported by helicopter and listed in critical condition at the Orlando Regional Medical Center. There were no injuries outside the plant.
"It was a tremendous fire," Richard Keith, the Tavares fire chief, said.
The Blue Rhino propane plant, which is located 30 miles northwest of Orlando, is stocked with 53,000 20-pound propane tanks, often used for backyard grilling. There was also three 90,000-gallon bulk tanks of propane at the facility that did not ignite in the fire, The Orlando Sentinel reported.
John Herrell of the Lake County Sheriff's Office said Tuesday morning that an evacuation zone had been reduced to a half-mile radius from an initial one-mile radius. To be sure, the nearest residential area is about a quarter-mile from the plant.
The Sentinel reports that the explosions began a little before 11 p.m. at the plant in Tavares.
The dozens of explosions were massive and nearby residents said their homes shook during the explosions.
"I thought we were being bombed," Debbie Stivender, a nearby resident, told the Sentinel.
Reuters spoke to a former plant supervisor who said the company cleans propane tanks, refills them and checks their valves. These tanks are then stacked on plastic pallets stacked about five high. On a normal night shift, these workers can refill up to 5,000 tanks.
The Associated Press contributed to this report.