I've read so many articles about these overdoses and these useless statistics but I still did not understand the problem until I listened to an expert on the radio.   I have never been a drug user so I have no first hand experience.   Fentanyl is being used to make Heroin.  Sometimes if the Fentanyl is not processed properly, you get small clumps that create over dose situations because Fentanyl is such a concentrated chemical.  It can also be smuggled in from other countries in small amounts like a chocolate bar size and be used to make a lot of Heroin.  In addition, the molecular composition can be easily changed to make a similar drug that acts like Fentanyl.  This makes it even harder to outlaw without creating a more robust law.