Native American communities have indeed been affected severely, but it's not clear how much is due to this particular type of Fentanyl:

AP news reported recently that: "Centers for Disease Control and Prevention figures indicate the increase [in opioid overdose deaths from 1999 to 2015] was higher for Native Americans than any other group ..."

https://www.apnews.com/81eb3ae96c2b4f6aae272ec50f0672d2