Carfentanil, a powerful opioid used to sedate elephants, is being blamed for a record spike in drug overdoses in the Midwest. It's much stronger, and riskier, than heroin or fentanyl.
U.S. drug officials have traced a sharp spike in the already climbing death toll from heroin overdoses to an additive — acetyl fentanyl. The fentanyl is being cooked up in clandestine labs in Mexico.