Gas-s-s-s

Gas-s-s-s (on-screen title: Gas! -Or- It Became Necessary to Destroy the World in Order to Save It.) is a 1970 American post-apocalyptic black comedy film directed by Roger Corman, written by George Armitage, and produced and released by American International Pictures. The plot follows survivors of an accidental military gas leak involving an experimental agent that kills everyone on Earth over the age of 25 (a cartoon title sequence shows a John Wayne-esque Army General announcing — and denouncing — the "accident"; the story picks up as the last of the victims are dying with social commentary on Medicare and Medicaid). The subtitle alludes to the 1968 quote "it became necessary to destroy the town to save it" attributed to a U.S. Army officer after the Battle of Bến Tre in Vietnam.

Robert Corff and Elaine Giftos star, with Ben Vereen, Cindy Williams, Bud Cort, and Talia Shire (credited as "Tally Coppola") in early roles. Country Joe McDonald, who provides the music, makes an appearance as a spokesman for "AM Radio".