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S. 331 · Where this bill is now

Became law

Public Law 119-26, Jul 16, 2025

What this bill does

In plain words · AI-written from the official summary

Permanently classifies fentanyl-related substances

This law puts fentanyl-related substances permanently into schedule I of the Controlled Substances Act, which means they're treated as drugs with high abuse potential and no accepted medical use. Offenses involving these substances are punished with the same quantity thresholds and penalties as fentanyl itself, so 100 grams or more triggers at least a 10-year prison sentence. The law also streamlines how researchers can register to study these controlled substances, allowing things like shared registrations across research sites and simplified inspection processes.

How it affects you

If you're involved in law enforcement or the criminal justice system, this law creates a clearer, broader framework for prosecuting fentanyl-related trafficking. Researchers who want to study these substances will find the registration process somewhat easier. For most people, this affects the legal consequences for trafficking these drugs and how they're controlled nationally.

Read the official summary (Public Law, Jul 17, 2025)

Halt All Lethal Trafficking of Fentanyl Act or the HALT Fentanyl Act

This act 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.

Under the act, offenses involving fentanyl-related substances are triggered by the same quantity thresholds and subject to the same penalties as offenses involving fentanyl analogues (e.g., offenses involving 100 grams or more trigger a 10-year mandatory minimum prison term).

Additionally, the act establishes a new, alternative registration process for certain schedule I research.

The act also makes several 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 act expresses the sense that Congress agrees with the interpretation of the Controlled Substances Act in United States v. McCray , a 2018 case decided by the U.S. District Court for the Western District of New York. In that case, the court held that butyryl fentanyl, a controlled substance, can be considered an analogue of fentanyl even though, under the Controlled Substances Act, the term controlled substance analogue specifically excludes a controlled substance.

Written by AI (Claude) using only the official summary by the Congressional Research Service, the Library of Congress’s nonpartisan research staff. It can miss nuance, so check the official summary and the bill text for details.

119th Congress
1st Session
S. 331

AN ACT

HALT Fentanyl Act

Passed SenateMar 14, 2025 · 84–16Passed HouseJun 12, 2025 · 321–104Public Law 119-26Jul 16, 2025

Sponsor: Sen. Bill Cassidy (R-LA) · Introduced Jan 30, 2025 · Crime and Law Enforcement · 4 versions of the text

Sources: Congress.gov actions and votes · bill text from GovInfo · latest official action Jul 16, 2025: “Became Public Law No: 119-26.”

How Congress voted

Official roll calls

House · On Passage · Jun 12, 2025

Passed 321–104

YesNoDidn’t vote
PartyYesNoDidn’t vote
Democrats1041035
Republicans21712

104 members voted against most of their party: 103 Democrats voted No and 1 Republicans voted No.

Source: Clerk of the House · roll call 166

321–104Passed
DemocratsRepublicans

Congress votes on whole bills and amendments, not on single sections.

Sections

Opens on the most recent version where something changed
Sections · 2
S. 331: HALT Fentanyl Act — Bill Status, Votes and Text · Public Law Tracker