Toxic additive prevalent in street fentanyl in the U.S. – but not in Canada

In North America, tracking the flow of illicit fentanyl, a deadly opioid that can be synthesized in a lab, is difficult. But the changing chemistry of the drug may offer clues.Recently, police and public health officials have taken note of a mysterious toxic industrial chemical that is showing up in street fentanyl in the United States – but not in Canada, despite U.S. President Donald Trump’s assertion that the drug is flowing south in massive quantities.