Titan II Accident McConnell AFB, Kansas 1978
The most dangerous part of the Titan II system from the maintenance standpoint were the propellants. Both were extremely toxic. The oxidizer, nitrogen tetroxide, was highly corrosive when dissolved in water. Therefore, all but the most minute of leaks of either fuel or oxidizer had to be taken seriously. With this considerable potential for catastrophic accident, large propellant spills were rare in the Titan II program. Ironically, the two largest oxidizer spills took place 14 years apart at the same site, Launch Complex 533-7, 381st SMW, McConnell AFB, Kansas.
The second spill took place on August 24th 1978. Launch Complex 533-7, located just south of the small town of Rock, Kansas, had been chosen for both a Reliability and Aging Surveillance Program evaluation of the launch complex and missile airframe and a Service Life Analysis Program evaluation of the Stage I and Stage II engines. Both of these tests were part of an ongoing analysis of the Titan II program designed to replace the launching of test missiles. The missile combat crew composed of 1Lt Keith E. Matthews, MCCC; 2Lt Charles B. Frost, DMCCC; A1C Danford M. Wong, BMAT; and SrA GLEN H. Wessel, MFT, was on duty monitoring the missile recycle operation. At 1200 a two-man Propellant Transfer System team was on Level 7 in the launch duct, finishing loading the Stage I oxidizer tank of the missile. Airmen 1st Class Erby Hepstall and Carl Malinger were engaged in the final steps of disconnecting the Stage I oxidizer propellant transfer hose from the oxidizer airborne quick-disconnect fitting at the bottom of the Stage I fuel tank. The Stage I oxidizer tank was located above the Stage I fuel tank with the oxidizer feed lines coming through the fuel tank to the engine attachment point. At 1220 Hepstall and Malinger had nearly completely unthreaded the transfer line fitting when the airborne (missile side) quick-disconnect poppet valve failed to seal. The 13,220 gallons of nitrogen tetroxide that had just been loaded into the Stage I oxidizer tank began to gush out, forcing them to drop the oxidizer fill line. The dark red clouds of vapor quickly cut visibility to zero inside the launch duct. The airmen screamed into the Radio-Type Maintenance Network (RTMN, a radio communication system used by the launch control center and topside propellant transfer control trailer staff), "The poppet did not seat, it won't stop, let's get out of here." Although Malinger and Hepstall were in the midst of a cloud of toxic oxidizer fumes, they were both wearing a rocket fuel handler's clothing outfit (RFHCO) and were in no immediate danger at this point.
Matthews was on Level 1 of the launch control center when the klaxon sounded, indicating oxidizer vapors present in the launch duct. He descended partway down the stairs to Level 2 where Frost advised him that the PTS team had just disconnected the transfer line. Matthews commented that a little vapor was normal and returned back to Level 1. The klaxon sounded again, and Frost heard a fragment of the message from the PTS team. Matthews quickly returned to the launch control center, and both officers tried without success to use the RTMN to establish contact with the PTS team.
Simultaneously, 2Lt Graham B. Sorenson, the site maintenance officer, was monitoring the operation from the control trailer on the surface. Upon hearing the screams of the ream members, Sorenson looked out the trailer window and saw clouds of vapor billowing out of the silo exhaust vent. Sorenson immediately left the control trailer to find SSgt Robert J. Thomas, the PTS team chief, who had left the control trailer to assist in repositioning equipment for the start of the fuel upload. Sorenson and Thomas ran back to the control trailer to find out what was happening. When Thomas heard that the poppet was not seated, he quickly left the trailer and entered the access portal, intent on rescuing his team members. A1C Mirl R. Linthicum, a PTS team chieft trainee, radioed to the PTS backup team to have a RFHCO suit ready for Thomas since he was going down to Level 7 to attempt to stop the flow of oxidizer. Sorenson radioed the security police at the end of the launch complex access road and advised them to stand by for evacuation of civilians in the area.
Before Thomas made it through Blast Doors 6 and 7, Hepstall had managed to find his way out of the launch duct on Level 7 and taken the elevator to Level 2 where he proceeded down the cableway to the backup PTS team position near the silo side of Blast Door 9. His helmet visor was clouded from direct exposure to liquid oxidizer, but he was uninjured. When Thomas entered the area, Hepstall informed his team chief of the situation and siad that he was going back down to find Malinger. Thomas suited up in RFHCO, Malinger changed his helmet, and they both left to find and assist Malinger. Airman Gary L. Christopher left the PTS position to return to the surface to retrieve additional RFHCO suits and air packs. A1C Francis A. Cousino, Liquid Fuels System inspector and evaluator, had come downstairs to the blast lock just as Hepstall returned for the second time, coughing badly as he stumbled and fell to the ground. Hepstall told Cousino that Malinger was trapped on Level 7 and that Thomas had descended in the silo elevator to get him. Sorenson and 2Lt Richard I. Bacon Jr., site maintenance officer trainee, arrived at the blast lock just as Hepstall finished changing his RFHCO and returned down the cableway. By this time oxidizer vapors had arrived at Blast Door 9 and were beginning to fill the area between Blast Door 8, which led to the launch control center and was shut, and Blast Door 9. Sorenson directed everyone in the room to evacuate topside.
Meanwhile, Matthews had tried to open Blast Door 8 in order to investigate what was happening. The RTMN was not working properly since too many people were trying to use it at once. Blast Door 8 would not open because of the interlock with Blast Door 9 that prevented both blast doors being opened at once. Matthews smelled oxidizer and told Wessel to set up a portable vapor detector to determine how much oxidizer vapor was leaking into the launch control center. A reading of 3 parts per million was close to the maximum allowable concentration. Wessel shut the blast dampers through which the vapors were coming, and Matthews directed him to open the escape hatch on Level 3 of the launch control center. Suddenly the portable vapor detector alarm sounded and them went silent as the concentration went past the full-scale reading. The missile combat crew donned CHEMOX masks and prepared to evacuate.
Hepstall managed to find Malinger and Thomas. Thomas had tried to directly stop the flow of oxidizer and was now injured; Malinger and Hepstall had pulled Thomas into the silo elevator and returned to Level 2. Either Hepstall of Malinger began calling for help on the RTMN. They reached Blast Door 9, which was closed but not locked. Opening Blast Door 9, Malinger or Hepstall called on the emergency phone for someone to unlock Blast Door 8 and help them.
Frost was still on Level 2 of the launch control center when he heard either Hepstall or Malinger call on the RTMN and asked that Blast Door 8 be opened. Frost replied that Blast Door 8 was locked and that they should evacuate up the access portal stairs. As he continued this conversation, the emergency phone in the launch control center rang. Frost answered and again stated that Blast Door 8 was locked. Much to his amazement, Blast Door 8 swung open, and Hepstall stumbled into the launch control center, followed by Malinger and a cloud of Oxidizer vapor. Both had their helmets off. Malinger was screaming that Thomas was dead. Matthews donned a fresh CHEMOX unit and went through the ope Blast Doors 8 and 9 to pull Thomas into the area between the two blast doors. Matthews, Malinger, and Frost together pulled Thomas into the launch control center and realized he was still alive as he moved his head from side to side. Matthews returned to Blast Door 8 and noted that he could see but a few feet in front of him due to the dense red-black oxidizer vapors. He closed but did not lock Blast Door 8.
Frost received a call from the wing command post and advised them that "the locks are on the safe and the keys are in it; we have one man possibly down and we're evacuating now." Frost turned around and saw that Thomas's helmet had been removed and his suit unzipped. Either Malinger or Hepstall had tried to administer mouth-to-mouth resuscitation.
At this point the personnel in the launch control center began to evacuate. Malinger and Matthews helped Hepstall down the stairs to Level 3 and the escape hatch. Matthews returned to Level 2 and determined that Thomas was dead. The crew and remaining PTS team members reached the surface amidst clouds of oxidizer vapor following them up the air intake that doubled as the escape route. Above-ground personnel assisted Malinger and Hepstall to a nearby water hydrant to wash off the remained oxidizer residue but found little water pressure. A section of the fence was removed and they evacuated the site, with the aid of security police, to a nearby farmhouse where both PTS team embers were washed down with water after their suits were removed. Frost contacted the wing command post and was instructed to take Hepstall and Malinger to a hospital in nearby Winfield. Evacuation of nearby civilians began, and a protective cordon isolating the launch complex was set up.
Sorenson and Bacon came to the farmhouse shortly after 1300. Linthicum and A1C John G. Korzenko volunteered to suit up and try to retrieve Thomas's body. The four returned to the complex, and Linthicum and Korzenko attempted to descend to the launch control center through the air intake shaft. Korzenko quickly returned to the surface since he smelled oxidizer in his suit, and Linthicum was right behind him since he found it too dark to see. At the direction of the wing commander no further retrieval attempts were made until additional PTS personnel and equipment reached the site.
The oxidizer fumes formed a cloud about 1 mile long and 1/2 mile wide and reached an altitude of approximately 1,000 feet. The town of Rock, Kansas, population approximately 200, located 2 1/2 miles north of the site, was evacuated at 1345 without incident. Only one civilian was treated for inhalation of oxidizer fumes.