David Wayne (Dr. Charles Dutton), Michael Pataki (Operator of 'The Hands'), Peter Hobbs (General Sparks), Glenn Langan (Cabinet Secretary), Ken Swofford (Toby (technician)), John Carter (MP Capt. Morton), Richard Bull (Air Force Major), Paula Kelly (Karen Anson), Ramon Bieri (Major Manchek), Robert 'Bob' Olen (Soldier), Lisa Daniels (Woman), Theodore Lehmann (Scientist), Tom McDonough (Stetson), Carl Reindel (Lt. Comroe), Carl B. Morrison (Minor Role), Paul Ballantyne (Hospital Director), Joe Billings (Scientist), Patty Bodeen (Girl), Michael Bow (MP at Stone's), Jan Burrell (Mother - Piedmont), Dee Carroll (Technician), Duke Cigrang (Father - Piedmont), Rhodie Cogan (Minor Role), Michael Crichton (Bearded Surgeon), Sandra de Bruin (Technician), Joe Di Reda (Wildfire Computer Sgt. Burk (as Joe DiReda)), Bill Dunbar (Vandenberg AFB Sergeant), Harold Dyrenforth, Sandra Ego (Girl), Don Ellis (Minor Role), Judy Farrell (Pam), Lance Fuller (Man), Ray Harris (Scientist), Peter Helm (Sgt. Crane (Piedmont team)), Rob Hughes (Air Force Technician), Mark Jenkins (Lt. Shawn (Piedmont team)), Sheila Jo Guthrie (Girl - Piedmont), Jason Johnson (Dr. Benedict), Bart La Rue (Medic Captain), Jamie Lamb (Boy - Piedmont), Johnny Lee (Boy), David McLean (Sen. McKenzie (New Mexico)), Cliff Medaugh (Civilian), Don Messick (Alarm Voice), George Mitchell (Jackson), Kermit Murdock (Dr. Robertson), Richard O'Brien (Grimes), Francisco Ortega (Gateman at Agricultural Center), Victoria Paige Meyerink, Alma Platt (Woman), Frances Reid (Clara Dutton), Clark Savage (M.P. Sergeant), Reuben Singer (Dr. Rudolph Karp), Robert Soto (Manuel Rios - Baby), Gilchrist Stuart (Man), Joan Swift (Decontamination Receptionist), James W. Gavin (Dempsey - Helicopter Pilot), Garry Walberg (Technician)

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Cinema International Corporation (CIC), Esselte CIC Video, Image Entertainment, MCA, MCA/Universal Home Video, National Broadcasting Company (NBC), Universal Home Entertainment, Universal Pictures