Inadvertent Chemical Conversion and TRI Reporting

Under EPCRA Section 313, manufacturing includes both deliberate and unintentional creation of listed toxic chemicals. This means that facilities must treat coincidental formation of a toxic chemical as manufacturing when calculating thresholds. Even if a chemical is formed unintentionally during another process, it still triggers reporting obligations.

Coincidental Formation in Industrial Processes

In pulp and paper mills, for example, metal carbonates and oxides naturally present in wood can convert into metal sulfides during pulping. This transformation counts as manufacturing under Section 313, even though the parent metal does not change. The newly formed compounds must be included in manufacturing threshold determinations.

Similar situations arise when chemicals used for pH control coincidentally manufacture another toxic chemical. If that chemical is then applied to a product such as coal and distributed in commerce, it cannot be treated as an impurity. By definition, an impurity is coincidentally manufactured during the processing of another chemical and remains with the product or mixture—not a substance created in a separate process and then added intentionally.

Distinguishing Impurities, Byproducts, and Processing

Whether a chemical is manufactured, processed, or exempt depends on how and why it is formed:

• Separate process manufacture — If a listed chemical is created during a process such as water treatment, it must be counted toward the manufacturing threshold.

• Incorporation into a product — If water and chemicals are intended to and become part of the final product, the listed chemical is considered processed.

• Byproducts and conversions — The de minimis exemption does not apply to toxic chemical byproducts generated during production. For instance, if impurities in raw materials are chemically converted into sulfates or chlorides during processing, those conversions are manufacturing and must be counted.

Even when the resulting chemical is in the same Section 313 category as the original impurity, the conversion itself is still treated as manufacturing and the totals must be included in threshold determinations and waste reporting.

Why This Matters for Compliance

These distinctions affect not only threshold calculations but also release reporting. Failing to count coincidental manufacture can result in underreporting, while misclassifying impurities or byproducts can lead to compliance gaps. Facilities must carefully evaluate chemical pathways, track transformations, and document their decisions to ensure reporting is both accurate and defensible.

How TRI Toolkit Can Help

The TRI Toolkit helps facilities manage these complex determinations by:

• Identifying Section 313 chemicals and categories with AI-powered parsing and data entry tools.

• Tracking manufacturing, processing, and otherwise use quantities in real time.

• Guiding users through exemptions, threshold modifications, and activity classifications.

With these tools, facilities can ensure that inadvertent conversions are properly captured, thresholds are accurate, and reports are defensible.

References

1. 2024 QA Consolidation #254 — Do covered facilities need to consider the inadvertent conversion of one metal compound to another as manufacturing? For example, a pulp and paper mill inadvertently converts metal carbonates and oxides in wood to metal sulfides during pulping. Is this a covered manufacturing activity?

2. 2024 QA Consolidation #417 — A facility adds a chemical to water for pH control that results in the coincidental manufacture of another toxic chemical. This chemical is then applied to coal that is further distributed in commerce. Is the generated chemical considered an impurity and eligible for the de minimis exemption?

3. 2024 QA Consolidation #419 — A covered facility produces a non-listed inorganic heavy metal oxide. The ores used as raw materials for the production of the metal oxide contain EPCRA section 313 toxic chemicals in small concentrations. During production, these impurities are chemically converted from oxides to sulfates or chlorides, separated from the main product stream, and discharged in wastes. At no point in the process does the concentration of an EPCRA section 313 toxic chemical (i.e., the sum of the concentrations of compounds falling into any listed chemical category) ever exceed the appropriate de minimis concentration. Can the de minimis exemption apply to these activities? Because the toxic chemicals being coincidentally manufactured are in the same EPCRA section 313 category, is the conversion considered manufacturing?