A powerful new adulterant contaminates fentanyl in the United States, but not Canada. Why?

The simultaneous arrival of a toxic chemical in the drug supply of nine states raises new questions about who controls the fentanyl supply chain

A RCMP officer stands ready to patrol the border next to one of the force’s new Blackhawk helicopters. A new adulterant sweeping the fentanyl supply in the US cannot be found in Canada, more evidence fentanyl is not arriving in the US from this country. But the stark contrast raises questions about who controls fentanyl markets and how.

The sudden, natio…