http://articles.latimes.com/1989-11-09/entertainment/ca-1378_1_charlton-heston
For Top-Secret Narration, Call Charlton Heston : Security: For six years, the actor has held the nation's highest Q clearance to enable him to narrate classified films and videotapes.
Private nuclear-weapon-control groups are prohibited from seeing the scenes that Heston narrated.
According to sources who have viewed it, the tape opens with Heston on a library-like set and proceeds to highly classified images of American and Soviet technicians setting up monitoring equipment at the Energy Department's Nevada Test Site. It is, said one source, "a rah-rah for the U.S. position on the test ban treaty . . . a booster film."
Barnett said that, unlike Heston's previous five top-secret Energy Department productions, "Trust but Verify" is intended for eventual public release.