Life Force - Season 1 Episode 4 Greenhouse Effect

Goodman is requested to treat an aggressive Japanese leaf worm disease that has apparently broken out on a farm, affecting its crops. After the group arrive, it transpires that the unscrupulous owner of the farm, Harry Fellside, is using illegal, highly toxic nerve agent chemicals to promote the growth of his plants, and ruthlessly forcing his captured 'climeys' (climate refugees) that have migrated from a similarly-flooded France into brutal lives of slave labour exploitation.