Updated February 2026 to discuss the special surveillance list
This blog post examine how List 1 and List 2 chemicals goes beyond simple named substances, also controlling similar chemicals.
Historically Controlled Drug precursors, also known as List 1 and list 2 regulated chemicals in the USA were controlled by naming defined, discrete chemicals within the Controlled Substances Act. This typically covered fairly common chemicals such as acetone or sulfuric acid, which can be used to manufacture controlled drugs.
More recent years has also seen more specific building blocks and intermediates being included.
However with this, the game of “whack a mole” then begins, as the illicit drug trade then switches to other very similar building blocks which then needs to be regulated as DEA List 1 or list 2 regulated chemical to allow authorities to track, identify and disrupt illicit usage.
May 2020 saw the DEA take a new approach to this, introducing chemical family / generic statement controls aimed at defining and controlling all related chemicals to the named DEA List 1 or list 2 regulated chemical, initially for N-phenylpiperidin-4-amine type chemicals
Then in May 2023 piperidone type chemicals were targeting by a chemical class type control as a DEA List 1 chemical.
These types of control have been used for many years to control actual narcotic/psychoactive substances (notably Cannabinoids and Opioids in the USA), but are new to the world of controlled drug precursors.
Most recently, in November 2023 the description of N-phenylpiperidin-4-amine was updated to further expand it to cover all halides.
"N-phenylpiperidin-4-amine, its amides, carbamates, halides and salts are designated as List I chemicals under the United States of America Controlled Substances Act (CSA).”
Visually in chemical notation, this looks like
As you can see it can cover 10,000s of possible chemicals based on N-phenylpiperidin-4-amine, all which are now regulated with reporting and licencing requirements.
This chemical family / generic statement control followed on from an earlier one for 4-piperidone
4-piperidone, its acetals, its amides, its carbamates, its salts and salts of its acetals, its amides, and its carbamates, and any combination thereof, are designated as list I chemicals under the United States of America Controlled Substances Act (CSA).
Visually in chemical notation, this looks like
In addition to the List 1 and List chemicals in the Controlled Substances Act, you should also consider the DEA special surveillance list
This was created in 1999 by the Attorney General covering addititional drug precursors and has largely gone under the radar. It doesn’t directly control the listed chemicals (like with actual List 1 and List 2 drug precursors in the Controlled Substances Act), but it does place the risk of civil fines for supplying these substances recklessly
“…The Controlled Substances Act provides for civil penalties for the distribution of a laboratory supply to a person who uses, or attempts to use, that laboratory supply to manufacture a controlled substance or a listed chemical, if that distribution was made with reckless disregard for the illegal uses to which such laboratory supply will be put. The term laboratory supply is defined as a listed chemical or any chemical, substance, or item on a special surveillance list published by the Attorney General which contains chemicals, products, materials, or equipment used in the manufacture of controlled substances and listed chemicals”
For 20 years the list has been static and quite small, however in 2023 the ability to update the list was transferred directly to the DEA which is now extending it.
“The Attorney General has delegated authority under the CSA and all subsequent amendments to the CSA to the Administrator of the DEA pursuant to 28 CFR 0.100. The Special Surveillance List may be updated as needed to reflect changes in the chemicals, products, materials, or equipment used in the manufacture of controlled substances and listed”
Although technically not controlled and not illegal to use or supply these chemicals, given that the DEA (Drug Enforcement Agency) has now been given direct authority to update the list and has done so twice in 2 years, it suggests an increase in the use and importance of this list in the DEA compliance efforts.
Substances previously on the special surveillance list have also been moved into list 1 or list 2.
It’s important to be able to correctly identify if your organization is using, storing, shipping or selling these controlled drug precursors as well as controlled substances under the Controlled Substances Act. The DEA can impose significant fines or prosecute companies and individuals who do not properly report and store these or hold the appropriate licenses.
However the sheer number of chemicals listed and complexity of the regulations can make it difficult to identify and track precursors and regulated chemicals you may have. Controlled Substances Squared, part of compliance hub, allows you to quickly and easily identify all your chemicals that are DEA List 1 and list 2 chemicals, e.g drug precursors, allowing you to ensure maximum compliance.
Its algorithms and database of controlled drugs and precursors are updated weekly to ensure you are always compliant.
About the author
Joe Bradley is a Biochemist with decades of experience in controlled drug regulations, drug discovery and cheminformatics. He has spent the last 12 years working to improve controlled drug and regulatory compliance within the chemicals and pharmaceuticals industry, through the development of software solutions which allows the rapid and accurate identification of controlled and regulated chemicals.
He founded Scitegrity in 2011 and the tools he helped create are now used by many of the worlds top chemical and pharmaceutical companies, specialist controlled drug suppliers and regulators.
He has consulted for regulators globally, helping to refine and assess the impact of proposed controlled drug regulations before final enactment.
When not absorbed in chemical regulations you'll find him on is skateboard, trials bike or with snooker cue in hand.
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