Chemicals giant Monsanto is believed to have reached a settlement with US residents who claim they were poisoned by chemicals used in the manufacturing of the Vietnam-era chemical weapon Agent Orange.

The long-running suit was brought by residents living near a now defunct Monsanto plant in Nitro, West Virginia that between 1949 and 1971 produced the agricultural herbicide 2,4,5 trichlorophenoxyacidic acid, a key ingredient in Agent Orange.