(Updates with details on biodiesel plant)
By Robert Gibbons
NEW YORK, Jan 22 (Reuters) - A fire raged at a biodiesel complex after an explosion that was felt miles away in northern Mississippi on Wednesday, the Highway Patrol said, but to its knowledge, all workers at the plant had been accounted for.
The fire at the plant, some 3-4 miles (5-6 km) north of New Albany, the Union County seat, broke out at about 5:30 a.m. CST (1130 GMT).
"The fire is still burning and they haven't started trying to fight it yet because of the intense heat," Trooper Ronny Hall, Mississippi Highway Patrol, said by telephone from the scene of the fire.
He spoke at around 10:00 CST, almost five hours after the fire began.
"At this time, we have had no injuries reported and all of the workers have been accounted for as far as we know," Hall said, adding he did not know who the owners of the plant were.
Earlier, in an interview with local television station Action News 5, Hall said the fire may burn for as long as two days.
"Until the fire calms down and emergency officials can come close to it, this is probably going to be here for, you know, maybe several hours or even a couple of days," Hall told the station.
While Hall said all workers were accounted for, he said authorities will know for certain whether there had been any injuries once they get access to the site, which they do not currently have.
He said the explosion likely took place at fuel storage tanks within the facility.
Biodiesel Magazine and directory websites list North Mississippi Biodiesel Inc as a biodiesel company operating close to New Albany and Google maps places the plant on Highway 15 close to New Albany.
A telephone number listed for the plant appeared to be disconnected and Reuters was unable to immediately locate plant officials.
The plant has a capacity to produce 7.5 million gallons (28.4 million liters) of fuel annually and is the smallest of three such facilities in the state, according to Biodiesel Magazine. The plant makes fuel from soybean oil and animal fats, traders said.
Asked about any environmental danger to the public, Hall said emergency management personnel from the state, federal and county had responded and were assessing the situation.
"Businesses across the road from the fire have been evacuated. Residences are far enough away that they have not had to be evacuated. We're trying to keep a 150- to 200-foot (45-60-meter) perimeter away from the fire."
The Union County emergency management office was contacted but did not return voicemail messages in time for this report. (Additional reporting and writing by Sabina Zawadzki in New York and Michael Hirtzer in Chicago; Editing by Alden Bentley and Marguerita Choy)