Lenoir County Emergency Services Director Murry Stroud said that one person was confirmed dead from the afternoon blast and three firefighters were hurt, one of them in critical condition.
Stroud said firefighters were dispatched to put out a reported brush fire at a farm at 4871 Bulltown Road in La Grange as flames were approaching a building containing commercial-grade fireworks.
He said fields were being burned off when the fire spread and detonated the fireworks stored in a container.
The property owner, Randy Herring died in the explosion, Stroud said Saturday.
The three injured firefighters were taken to ECU Health Medical Center in Greenville. Two of them have been released.
The third firefighter was more seriously injured and was taken to the NC Jaycee Burn Center in Chapel Hill for further treatment.
Fire departments from Lenoir County, Wayne County, Johnston County and Duplin County worked through the night to contain the fire and fully extinguish hot spots.
The Lenoir County Fire Marshal's Office is coordinating the investigation with the North Carolina State Bureau of Investigation, the North Carolina Office of the State Fire Marshal, the NC Forest Service, and the Bureau of Alcohol, Tobacco, Firearms and Explosives.