The Belgian organization "Early warning of drug addiction" warns of a powder containing otsfentanil that is "especially dangerous to health."

Otsfentanil – a chemical derivative of fentanyl, is a powerful anesthetic. It is used, for example, in surgery or prescribed to patients having the final stages of cancer.
Otsfentanil belongs to the category of opiates, like heroin.

The main risk is that otsfentanil is an active substance, which comprises hundreds times more opiates than even heroin.

bbabo.Net