Two other works were injured.
Jackson County Coroner Vicki Broadus identified the victim of Friday's incident as Jeremy Moore, 20, of Moss Point.
The two injured workers were taken to Singing River Hospital in Pascagoula, but authorities say one patient will be transferred to USA Medical Center's Burn Unit in Mobile.
Jackson County Sheriff Mike Byrd says there was some sort of steam explosion at the plant. He said his investigators and coroner Vicki Broadus were on the scene at 7:15 a.m.
"The incident was and is contained within the plant. The facility is stable, but out of caution, operations have ceased. There is no threat to employees or the public," the company said in a statement.
"We are working closely with response personnel and cooperating with all governmental and regulatory agencies. We are continuing to gather information and working to identify the cause of the accident."
Friday's incident is the second deadly accident at this plant in the past two weeks. Byrd said this explosion occurred in the same area as the last accident.
On May 21, Jeffrey Simpson, 39, was killed at the plant where he worked as a board operator. In that incident, company officials said the accident occurred during a maintenance procedure in a portion of the plant that was not operational at the time.
Earl Etheridge, state on-scene coordinator for the state Department of Environmental Quality, said there was no danger to the public or the environment. He said plant officials report no chemical release.
Madison, Miss.-based Mississippi Phosphates Corp. manufactures a fertilizer, diammonium phosphate, at the Pascagoula facility.