Save Americans from the Fentanyl Emergency Act or the SAFE Act This bill permanently places fentanyl-related substances as a class into schedule I of the Controlled Substances Act. A schedule I controlled substance is a drug, substance, or chemical that has a high potential for abuse; has no currently accepted medical value; and is subject to regulatory controls and administrative, civil, and criminal penalties under the Controlled Substances Act. The temporary scheduling order issued by the Drug Enforcement Administration to place fentanyl-related substances into schedule I of the Controlled Substances Act expires on December 31, 2024. It limits the application of mandatory minimum penalties for certain offenses involving fentanyl-related substances, establishes a process to deschedule or remove certain fentanyl-related substances that have a low potential for abuse, and allows a federal court to vacate or reduce the sentence for convictions of offenses involving a fentanyl-related substance that is descheduled or moved to a schedule other than schedule I or II. The bill establishes a new, alternative registration process for schedule I research. It also makes other changes to registration requirements for conducting research with controlled substances, including permitting a single registration for related research sites in certain circumstances, waiving the requirement for a new inspection in certain situations, and allowing a registered researcher to perform certain manufacturing activities with small quantities of a substance without obtaining a manufacturing registration. Finally, the bill requires the Government Accountability Office to analyze the implementation and impact of permanently placing fentanyl-related substances into schedule I of the Controlled Substances Act.