The controlled substance known as BZP, when combined with another chemical, known as TFMPP, which is not a controlled substance, is frequently sold as MDMA (ecstasy) and has a somewhat similar effect on the user. However, there is no Guideline in U.S.S.G. § 2D1.1 for BZP or the BZP/TFMPP combination.
When sentencing for a drug "not specifically referenced" in the Guidelines, application note 5 to § 2D1.1 directs the use of the "most closely related" controlled substance, and gives three criteria for comparison - chemical structure, effect on the central nervous system and potency.
In this opinion, the court affirms the district court's conclusion that BZP/TFMPP is most closely related to ecstasy.