Described as “the first film ever made in the US of labour, by labour, and for labour”, Salt of the Earth depicts the 1950 strike of mineworkers in New Mexico. Demonised and suppressed on its release, the production was besieged by mobs of anti-communist vigilantes, the leading actress deported to Mexico, and the main creative and production team persecuted for their refusal to cooperate with the House Committee on Un-American Activities.