List I precursor actions of 2026: two designations final, two still proposed

Two List I precursor chemicals — propionyl chloride and P2P methyl glycidic acid — became controlled under the Controlled Substances Act in 2026, with effective dates of April 9 and May 4; two more, phenethyl halides and additional esters of 3,4-MDP-2-P methyl glycidic acid, remain proposals that have not taken effect.

Propionyl chloride is now a List I chemical under the Controlled Substances Act, effective since April 9, 2026 [1]. Every transaction involving it, of any size, is regulated [1], no concentration is exempt in mixtures [1], and no minimum threshold applies [1]. It is used in the illicit manufacture of fentanyl, fentanyl analogues, and fentanyl-related substances [1]. Handlers who wanted to keep operating pending DEA's final action had to apply for registration before that date [1].

P2P methyl glycidic acid — including its esters, isomers, and salts — became a List I chemical on May 4, 2026 [2], under the same terms: every transaction regulated regardless of size [2], no exemption for mixtures at any concentration [2], no threshold [2]. It figures in the illicit manufacture of phenylacetone, methamphetamine, and amphetamine [2]. Registration to continue handling it pending final action was due by the same date [2].

The other two actions are proposals, not yet law. The DEA is proposing to add phenethyl halides — used in the illicit manufacture of fentanyl, fentanyl analogues, and fentanyl-related substances [3] — to List I [3]. If finalized, handlers would become subject to the CSA's chemical regulatory provisions [3], with no threshold for transactions of any size or concentration [3]. Comments on this proposal are due by August 10, 2026 [3]. Nothing about phenethyl halides is currently controlled by reason of this docket.

The DEA is also proposing to amend the existing List I entry for 3,4-MDP-2-P methyl glycidic acid — used in the manufacture of MDMA and other 'ecstasy'-like substances [4] — to add seven additional esters not already covered [4]. The current listing already covers the acid's salts and its optical and geometric isomers [4]; this proposal only extends the ester coverage. If finalized, it would bring handlers of those esters under the CSA's regulatory provisions [4], with no threshold [4] and no exemption for mixtures at any concentration [4]. Comments are due by September 2, 2026 [4]. Until a final rule publishes, those additional esters remain outside List I control.

References

1. Designation of Propionyl Chloride as a List I Chemical — Federal Register
2. Designation of P2P Methyl Glycidic Acid as a List I Chemical — Federal Register
3. Designation of Phenethyl Halides as List I Chemicals — Federal Register
4. Amendment to 3,4-MDP-2-P Methyl Glycidic Acid, a List I Chemical — Federal Register