A fiery explosion early Wednesday at Hercules' Bacchus West works damaged a $15 million rocket-fuel mixing building where fuel was being prepared for a Delta II space booster rocket motor.

No one was hurt in the 12:05 a.m. explosion at Building No. 2 at the Bacchus West plant, said Ted Olsen, media relations manager. Eight to 10 people were operating robot control equipment from a building several hundred yards away."There was both an explosion and a fire during mixing operations," Olsen said. "There was nobody in the building."

The mixing operations are automated and in some cases handled by robots "so personnel exposure is reduced to a minimum," he said.

Equipment in the building had the capacity for mixing 25,000 pounds of rocket fuel - the largest mixing capacity in the aerospace business, Olsen said.

The building was surrounded by bunkers and is situated in the foothills of the Oquirrh Mountains about 11/2 miles west of U-111 (84th West) near 50th South.

Hercules spokesman David Nicponski said the Wednesday morning explosion is the first accident of its kind at the plant since 1975.

Top-level management personnel responded to the scene immediately after the explosion, along with safety and security officials who were assessing the damage and investigating the cause of the explosion later Wednesday morning.

Officials are assessing the possible effect the blast will have on the production schedule for the Delta II rocket and other military rockets being built at the plant, said Jack F. DeMann, director of public affairs.

Of Hercules' Delta II contract, Olsen said, "It's not one of the biggest, but it's one of the more significant space contracts."

Hercules also manufactures rocket motors for the Titan IV, Trident II and MX "Peacekeeper" missiles.

The Delta II rocket has a liquid-fuel motor surrounded by nine solid-fuel rocket boosters. Hercules manufacturers the solid-fuel rocket boosters, DeMann said.

A third propellant mixing building is already under construction and older, smaller mixing plants may be used to help keep rocket production on schedule until the damaged building can be repaired.

DeMann said the explosion was mostly contained within the mixing building, which has steel-reinforced interior and exterior walls separated by a 10-foot wide earthen buffer.

Vice President and General Manager Ruth Novak said in a written statement that Hercules is assessing the situation and that everything at the plant is under control. She said Hercules' firefighters and security officers were able to handle the incident without outside help, and she thanked county and West Valley City firefighters for responding in case they were needed.

"The fact that the mix facility was designed to contain such incidents, that the production process is completely automated and roboticized, and that our production people were following procedures kept them away from the building and safe," Novak said.