We see a little E Coli in Nestlé Toll House cookie dough and 300,000 cases are recalled and destroyed. I do not know, however, if drug contamination could be successfully pulled off because of the legal liability. If it was done surreptitious, where it could not be traced to the U.S. Government, it might work. I would not support something deadly. If the person temporarily turned green so they got the mark of the Beast that identified them as a drug user, that would be best. Once the user understood there was a chance they could turn green, it would be the same effect as those Toll House cookies. I am sure we have biochemists that could come up with a similar technology.
On day two, when the first round of junkies have dropped, announce it and offer help quitting. They'd consider turning green a badge of honor, and green makeup would be sold out to leftists who support the druggie lifestyle if they don't use themselves. But the prospect of death, not so much.