See https://pmc.ncbi.nlm.nih.gov/articles/PMC4407437/ to verify that PAS was used.

Any google search on PAS and manganese will show that it eliminates manganese from the body by chelating it, and is therefore used for treating manganese toxicity.

I don't have a specific reference for manganese levels in people undergoing the old TB treatment. But I'm sure that it should exist somewhere.