File image of Titan 4 rocket at Complex 40. Photo: Lockheed Martin

Work to clean up the nitrogen tetroxide spill at Cape Canaveral's Complex 40 has been completed, the Air Force said Thursday, but liftoff of the Titan 4 rocket has been pushed back one additional day.

Normal operations have resumed at the launch pad and liftoff is now targeted for Wednesday, August 20, officials announced. That is a two-day delay for the mission, which will place a classified national security satellite cargo into space.

The launch period extends from 0340-0900 GMT (11:40 p.m. EDT Tuesday to 5 a.m. EDT Wednesday). The actual window in which the rocket can launch remains a secret. The window falls within that period.

About 40 gallons of the toxic oxidizer leaked Tuesday when a pump in ground equipment failed as the rocket's second stage was being fueled for flight.

No one was injured due to the leak and there was no damage to the launch vehicle.

"Preliminary findings indicate that during the Stage 2 load of the propellant, an oxidizer pump motor failed. The release occurred in the oxidizer holding area, a support facility for the Titan 4; the entire launch complex was evacuated," the 45th Space Wing said in a statement Thursday.

"An estimated 40 gallons leaked during the incident. The oxidizer and pump system were isolated from the rest of the rocket systems for inspection, and the crew found no additional leaks.

"The investigation into the pump motor failure is ongoing," the Air Force statement said.