The Drug Enforcement Agency finalized the placement of five fentanyl substances in Schedule I of the Controlled Substances Act.

Furanyl fentanyl, 4-fluoroisobutyryl fentanyl, acryl fentanyl, tetrahydrofuranyl fentanyl and ocfentanil were temporarily placed in Schedule I multiple times in the last few years, after the government determined that they had no medically accepted uses in treatment and posed a threat to public safety.

The substances will now remain permanently in a class of substances that includes heroin, LSD, marijuana, peyote and ecstasy.