So much this. From Wikipedia: "Whether any injury came about due to the inhalation of paraquat-contaminated marijuana is uncertain. A 1995 study found that "n

So much this. From Wikipedia: "Whether any injury came about due to the inhalation of paraquat-contaminated marijuana is uncertain. A 1995 study found that "no lung or other injury in cannabis users has ever been attributed to paraquat contamination". Also a United States Environmental Protection Agency manual states: "... toxic effects caused by this mechanism have been either very rare or nonexistent. Most paraquat that contaminates cannabis is pyrolyzed during smoking to dipyridyl, which is a product of combustion of the leaf material itself (including cannabis) and presents little toxic hazard."