Four people remained in critical condition this morning at a Georgia burn center from injuries sustained in Saturday’s explosion at International Paper’s Vicksburg Mill that left one dead, a hospital spokesman said.

The four burn victims, along with another who was listed in good condition, were admitted to Joseph M. Still Burn Center in Augusta Saturday night after being flown there for specialized treatment. All five were working at the mill off Mississippi 3 as contract employees when one of the mill’s two recovery boilers exploded.

The contract employees had been hired to assist the mill in restarting operations after its annual shutdown for maintenance and repairs. IP officials have not released their names, saying they were not IP employees, but have also declined to identify the contractors hired to perform the maintenance tasks.

Also, Amy Sawyer, IP spokesman, said this morning that the cause of the blast was still undetermined. “We don’t anticipate reaching anything conclusive for a little while,” she said. “It’s going to be days at least.”

The explosion occurred at 3:05 p.m. Saturday and took the life of 28-year-old Marcus Broome of Bolton. Broome, also a contract employee, was the father of twin 4-year-old girls. His funeral was scheduled for 2 p.m. Tuesday at Bethesda Presbyterian Church in Edwards, the family said this morning. Visitation is from 4 until 8 tonight at Glenwood Funeral Home in Vicksburg.

Broome was pronounced dead at the scene. Seventeen others were taken to River Region Medical Center. Diane Gawronski, a hospital spokesman, said those not taken to the Georgia burn center had been treated and released from River Region Saturday.

About 400 people, including IP’s 306 regular employees, were at the mill when the boiler exploded, said Tom Macher, mill manager. Macher also noted that he believed it was the mill’s first explosion during its 40-year history.

The plant is west of Mississippi 3 north of Redwood. It is a major local employer and transforms pulpwood into heavy paper on a production line.

The Warren County Sheriff’s Department and Vicksburg and Warren County fire units were on site Saturday afternoon and federal Occupational Health and Safety Administration representatives arrived later to begin the required investigation. Operations at the mill were on hold for the remainder of Saturday, for the most part, until safety inspections were completed, said IP managers.

According to Sawyer, employees of the Vicksburg mill were back on their normal shifts Sunday.

International Paper has manufacturing operations in North America, Europe, Latin America, Russia, Asia and North Africa. The company has about 51,500 employees, 33,100 in the United States.

The IP explosion comes about two weeks before the sixth anniversary of a deadly blast at the Rouse Polymerics plant on U.S. 61 South. Five people were killed, and seven injured.