Sentence:  Manganism has been known about since the 19th century, when miners exposed to ores containing manganese ... began to totter, slur their speech and behave like someone inebriated. The poisoning was irreversible, and soon ended in psychosis and death. Nowadays <WSD>workers</WSD> are exposed to far lower doses and manganism is rare. 
Meaning of the word marked with <WSD> tags:  A person who performs labor for a living, especially manual labor.