Q.01

How do I check if a chemical is on the TSCA Inventory?

The quickest check is to look up the chemical's CAS Registry Number in the EPA TSCA Chemical Substance Inventory (the TSCA section 8(b) list). Then read two things in the result: whether the substance is listed, and whether it is flagged ACTIVE or INACTIVE. I can run that lookup for you. Send me a CAS number (or several) and I'll give you the listing status, with citations.

How the check works

  1. Search by CAS number, with the dashes. Formaldehyde, for example, is on the public Inventory as CAS 50-00-0, status ACTIVE [1]. Searching by name works too, but synonyms and trade names can miss the listing, so CAS is more reliable.
  2. Read the activity status. Being listed is not enough. Under the 2017 TSCA Inventory reset, ACTIVE substances are in US commerce. An INACTIVE substance is still on the Inventory, but you would have to notify EPA before manufacturing or importing it again.
  3. Check the regulatory flags. Some entries carry EPA flags, such as XU (exempt from Chemical Data Reporting) or PMN (the substance came onto the Inventory through a premanufacture notice). These flags can attach use conditions or reporting consequences.
  4. If there's no public match, check the confidential part of the Inventory. Substances whose names are claimed confidential appear only under a generic name, with an EPA Accession Number and PMN number, and no CAS number. For example, "Polymer polyol isocyanate polymer (PROVISIONAL)", Accession No. 151076, PMN P931705, flags PMN and XU, status ACTIVE [2]. A generic name alone won't confirm that your substance is the listed one. For that, you file a bona fide intent to manufacture request with EPA.
  5. UVCBs (substances of unknown or variable composition, such as reaction products and natural extracts) are flagged as UVCB and often have a definition field. Compare that definition with how you actually make the substance, not just the CAS number.

Not finding a substance on the Inventory doesn't prove it's excluded from TSCA. It may be exempt (for example, some polymers or R&D quantities), regulated under a different law (pesticides, drugs, food additives), or listed confidentially. Otherwise, you would generally need to file a PMN before manufacturing or importing it.

Approach: I used the US EPA TSCA Chemical Substance Inventory, which has both public (CAS-numbered) and confidential (accession-numbered) listings, and ran the example lookups above.

Q.02

What do active, inactive and confidential listings mean?

On the TSCA Inventory, a listing has two separate attributes. Active/inactive tells you whether the substance is in US commerce. Public/confidential tells you whether its specific chemical identity is disclosed. Any combination is possible: a confidential listing can be active or inactive, and so can a public one.

Active vs. inactive (commercial activity status)

  • Where it comes from: EPA's Inventory Notification (Active-Inactive) Rule had industry report what was manufactured (including imported) or processed in the US over the 10 years ending June 21, 2016. That reporting closed on October 5, 2018, and EPA used it to designate each substance active or inactive (EPA, Active-Inactive Rule).
  • Active: EPA describes active substances as "known to be in use (active) in U.S. commerce." It counts 42,698 of them (EPA, How to access the TSCA Inventory). Example: zirconium hydride, CAS 7704-99-6, is ACTIVE [3].
  • Inactive: EPA says 44,043 substances are on the inactive list, "which means they are no longer used in U.S. commerce" (EPA). An inactive substance is still on the Inventory, so it is not a "new" substance and doesn't need a PMN. Example: zymosans, CAS 9010-72-4, INACTIVE [4].
  • What changes if it's inactive: since August 5, 2019, manufacturers and processors "are required to notify EPA before reintroducing inactive substances into U.S. commerce," using Notice of Activity Form B in EPA's Central Data Exchange (CDX). EPA then changes the substance to active (EPA). EPA describes the timing as before reintroduction (set by the statute), but not more than 90 days before (set by the rule). One correction to my last answer: this duty applies to processors too, not only manufacturers and importers.
  • When an inactive designation takes effect: 90 days after EPA identifies the substance for it. If you are already making or processing the substance, you may file Form B before that date to avoid any interruption. Filing Form B on time does not fix a missed retrospective report (EPA Active-Inactive Q&A, Q11g).

Public vs. confidential listings

  • Public listings show the specific chemical name and a CAS number.
  • Confidential listings are substances whose specific chemical identity has been claimed as confidential business information (CBI). The public data shows only a generic name and an EPA accession number. EPA publishes the non-confidential data for these listings in its PMNACC file (EPA). The records carry no CAS number and often include a PMN number and flags. Examples:
    • "Zirconium lysine complex", accession 234334, PMN P090356, flags PMN and S, ACTIVE [5]
    • "Zirconium (4+) alkanolamine polyol complex (PROVISIONAL)", accession 100799, INACTIVE [6]
  • What it means for you: a generic name can't confirm that your substance is the one listed. EPA also notes that a substance's presence on the confidential part of the Inventory may not be "known to or reasonably ascertainable by" a company that didn't make the CBI claim. It treats public listings differently (Q&A, Q5).
  • CBI claims under the reset: processors had a chance to ask EPA to keep existing confidentiality claims (Q&A, Q8). EPA finalised a separate rule on reviewing CBI claims for active substances on February 19, 2020 (EPA). EPA's page refers out to the Federal Register notice for the substantiation and review procedures and doesn't set them out itself.

Approach: I used the US EPA TSCA Chemical Substance Inventory for the example listings, plus EPA's Active-Inactive Rule pages and Q&A for what the designations mean. I couldn't open the rule text itself (40 CFR Part 710 on eCFR), so the details above come from EPA's own pages, not the codified definitions.

Q.03