JACKSONVILLE, Fla. -- The U.S. Chemical Safety Board on Friday announced preliminary results of its investigation, saying investigators believe the T2 Laboratory's chemical reactor ruptured.

More than 100 firefighters and every hazardous-materials unit in Jacksonville battled what a spokesman called a "hellish inferno" that followed the Dec. 19 explosion.

Pieces of the plant's reactor were found as far as a quarter-mile away from the Northside chemical plant, according to investigators.

Investigators said they believe the reactor ruptured during the production of a gasoline additive.

The blast killed Robert Scott Gallagher; Charles Budds Bolchoz, 48; Karey Renard Henry, 35; and Parrish Lamar Ashley, 36.

Fourteen other people were hospitalized for chemical exposure or their injuries after the blast.

Gallagher, the co-owner of the business, was laid to rest Friday morning as those who knew the 49-year-old gathered to honor his life.

Services were held at the Southside United Methodist Church.

Meanwhile, CSB remained in Jacksonville, interviewing survivors of the explosion.

A formal briefing is expected to be held next week. Chemical contamination of the site was being cleaned up.