Although the herbicide paraquat is not a therapy drug, it is cited in Pneumotox because it is a pulmonary toxin that is still used in suicide attempts in some countries. Typically, paraquat (even after being a pplied topically) can cause acute respiratory failure, ARDS and pulmonary fibrosis in survivors. Paraquat may contaminate nutrients, alcoholic beverages and illegal substances of abuse. Paraquat has medical-legal implications as cases of deliberate poisoning by proxy have been reported. Most western countries have now banned paraquat. When in doubt, measurement of paraquat in blood and/or urine is key. PMID 1892020 (imaging features) and 27160134.