Chemical Categories and Reporting Requirements

Chemical categories under EPCRA Section 313 are often broader than facilities expect. For example, the nickel compounds category covers all nickel compounds, even when the toxicological profiles of individual compounds differ. EPA retains the authority to remove members that no longer meet the scientific criteria for inclusion, keeping the list accurate and justified.

EPA divides chemical categories into two main types:

• Delimited categories are limited to a defined set of chemicals specifically named by EPA. Facilities must sum activity across only those members.

• Nondelimited categories extend more broadly to any chemical that contains the named compound or meets a stated formula. These require evaluating a wider range of substances.

In either case, if a facility exceeds the threshold for any single member, reporting is required for the entire category.

Special Treatment of Certain Chemicals

Not all chemicals fit neatly into categories, and some require special consideration:

• Nitrite compounds are not a listed category, but sodium nitrite is individually listed. Facilities must report sodium nitrite if thresholds for manufacture, processing, or otherwise use are exceeded.

• Chemical transformations can change reporting obligations. For example, barium chloride converted into barium sulfate is considered treatment for destruction, because barium sulfate is excluded from Section 313. In this case, reporting applies to the barium chloride transferred for treatment, not the resulting barium sulfate.

  
  

Why Records and Documentation Matter

Effective TRI compliance depends on three fundamentals:

• Correctly categorizing chemicals and distinguishing between delimited and nondelimited categories.

• Aggregating activity across all category members to determine thresholds.

• Recognizing when chemical transformations change reportability.

Clear records documenting supplier data, concentrations, and calculations reduce uncertainty and provide a defensible foundation if EPA questions reporting decisions.

How TRI Toolkit Can Help

The TRI Toolkit streamlines category management and threshold determinations by:

• Identifying Section 313 chemicals and categories using AI-powered SDS parsing, simple imports, and a proprietary compliance database.

• Comparing facility data against EPA thresholds in real time.

• Guiding users through exemptions and threshold modifications.

• Generating EPA-ready Form R XML files for TRI-MEweb submissions.

• Archiving past submissions for quick reference and audit readiness.

References

1. 2024 QA Consolidation #19 — Do the toxic chemical categories such as nickel compounds include all compounds, even those that have not been associated with adverse health effects? What is the authority for this decision?

2. 2024 QA Consolidation #499 — The EPCRA section 313 toxic chemical list contains delimited chemical categories. A delimited category includes a finite number of chemicals specifically designated by EPA to be included as part of that category. Are threshold determinations and release and other waste management calculations for these three delimited chemical categories different than threshold determinations and release and other waste management calculations for other EPCRA section 313 listed chemical categories?

3. 2024 QA Consolidation #561 — EPCRA section 313 requires covered facilities to report information on releases and other waste management of TRI-listed chemicals. Are nitrite compounds considered a listed toxic chemical category or are any individual nitrite compounds TRI-listed for the purposes of Section 313 threshold and release and waste management determinations?

4. 2024 QA Consolidation #563 — Waste containing barium chloride is shipped off-site to a RCRA treatment, storage, or disposal (TSD) facility. The TSD facility treats the barium chloride, converting it to barium sulfate. The barium sulfate is stabilized and subsequently disposed. Since barium sulfate is excluded from the EPCRA section 313 barium compounds category, should the barium chloride be reported as shipped off-site for treatment or transferred off-site for disposal?

5. 2024 QA Consolidation #867 — If a mixture contains a listed toxic chemical compound that is a member of a reportable Section 313 toxic chemical category, how should that be addressed on the supplier notification? Is it acceptable to provide the percent of the parent metal?