The most reliable evidence showing the presence of illicitly-manufactured fentanyls and synthetic opioids in the illicit drug supply comes from reports by the U.S. Drug Enforcement Administration (DEA) which contain information on drug seizures and analyses from the National Forensic Laboratory Information System (NFLIS).  

In 2019, they determined that availability was high across the country in the majority of the DEA’s Field Divisions. Reports of illicitly-manufactured fentanyls in the NFLIS increased by 12% between 2018 and 2019. Seizures predominantly occurred along the southwest border and were recorded in states with high heroin seizures as well since those markets are interconnected, including the Mid-Atlantic, Great Lakes, and Northeast regions. However, illicitly-manufactured fentanyls and synthetic opioids have been increasingly detected in counterfeit prescription pills in states across the country as well.

The DEA’s Special Testing and Research Laboratory’s (STRL) Fentanyl Signature Profiling Program (FSPP) data suggests that illicitly-manufactured fentanyl is rarely mixed into the heroin supply at the wholesale level, but likely at the regional and local level. The FSPP has also determined that the majority of illicitly-manufactured fentanyls found in the country are sourced from Mexico. Those sourced from China have rapidly declined in recent years.