Reporting Thresholds for Toxic Chemicals in Solid Metals

When solid metals contain listed toxic chemicals, threshold calculations under EPCRA Section 313 are based on the total weight of each toxic chemical, not the total weight of the metal itself. Steel, for example, is treated as a mixture rather than a compound. This means you calculate thresholds using the chemical content within the steel, ensuring reporting decisions align with EPA requirements.

How to Calculate the Chemical Content

The first step is to determine the concentration of the toxic chemical in the material. For threshold determinations, use the total weight of the compound that contains the listed chemical. Multiply the total weight of the steel by the weight percent of the compound to find the pounds attributable for threshold purposes.

Example: 10,000 pounds of steel at 5 percent chromium contains 500 pounds of chromium for threshold calculations.

For release reporting, however, you must convert that compound weight into the weight of the elemental toxic chemical actually released. This requires applying stoichiometric conversion factors so that releases are reported on an elemental basis, consistent with EPA’s TRI requirements.

This calculation must be repeated for each listed toxic chemical present in your materials. Maintaining records of weights, concentrations, and activity types—whether manufacturing, processing, or otherwise using—is essential for accurate annual threshold checks and defensible TRI determinations.

Applying Thresholds in Practice

For processing activities, the threshold for most non-PBT toxic chemicals is 25,000 pounds per reporting year. Consider the following example:

• A facility processes 30,000 pounds of steel that contains 10 percent chromium.

• The facility is therefore processing 3,000 pounds of chromium.

• Because 3,000 pounds is below the 25,000-pound threshold, no report is required for chromium in this case.

  
  

While the math may look straightforward, small errors in concentration data, product weights, or activity totals can compound quickly across product lines and over the course of a year. A minor miscalculation can turn into an avoidable reporting obligation—or worse, a compliance error.

Why Documentation Matters

Accurate documentation of concentrations, weights, and calculations is the foundation of reliable TRI reporting. Facilities that track and record their assumptions, data sources, and calculations reduce uncertainty and strengthen their ability to defend decisions in the event of an EPA review. The difference between a confident “no report required” decision and an unexpected filing often comes down to recordkeeping discipline.

How TRI Toolkit Can Help

The TRI Toolkit simplifies mixture calculations and threshold determinations by:

• Importing facility chemical data to identify Section 313 chemicals.

• Calculating chemical weights based on concentrations and total material quantities.

• Comparing activity data against EPA thresholds in real time.

• Tracking manufacturing, processing, and otherwise use with built-in guidance on exemptions.

• Running completeness and consistency checks to support audit-ready Form R submissions.

With these tools, facilities can avoid errors, streamline reporting, and ensure their decisions are both accurate and defensible.

References

1. 2024 QA Consolidation #274 — A facility subject to the reporting requirements of EPCRA 313 manufactures shoes that contain two toxic chemicals when they are distributed in commerce. Toxic chemical A exists as an impurity in a raw material that becomes part of the shoes. The toxic chemical remains in the product, but serves no specific function within it. Toxic chemical B is a solvent in the adhesive that is used to attach the soles of the shoes. Most of chemical B evaporates during the manufacturing process, but small amounts of this chemical remain in the shoes when they are distributed in commerce. How can a facility determine whether to apply the processing or otherwise use threshold in these situations?