UNITED STATES COURT OF INTERNATIONAL TRADE

Slip Op.  25-53

Before the Court in Mitsubishi Power Americas, Inc. v. United States, Court No. 21-00573, Slip Op. 25-53 (April 29, 2025) were cross motions for summary judgment concerning U.S. Customs and Border Protection’s (“CBP”) classification of selective catalytic reduction (“SCR”) catalyst blocks under Harmonized Tariff Schedule of the United States (HTSUS) heading 8421. The U.S. Court of International Trade was called upon to decide whether the SCR catalyst blocks imported by Mitsubishi fall under this heading, which provides for “Centrifuges, including centrifugal dryers; filtering or purifying machinery and apparatus, for liquids or gases; parts thereof,” or heading 3815, which provides for “Reaction initiators, reaction accelerators and catalytic preparations, not elsewhere specified or included”.

Mitsubishi contended that the SCR catalyst blocks are properly classified under HTS subheading 3815.19.00 because the SCR catalyst blocks are made of a combination of active catalytic chemical compounds and support material. Mitsubishi imported these products from China in multiple entries made from July 2018 to September 2020. The government argued that HTS subheading 8421.39.80 was appropriate because the SCR catalyst blocks serve as a gas filtering or purifying apparatus. In reclassifying the goods, Customs applied a 25% retaliatory tariff pursuant to Section 301 of the Trade Act of 1974. Mitsubishi timely protested Customs’ classification of the SCR catalyst blocks and argued the SCR catalyst blocks are properly classified under subheading 3815.19.00 because the SCR catalyst blocks facilitate and sustain the reaction of nitrous oxides (“NOx”) and ammonia. Furthermore, Mitsubishi argued that this classification prevented the SCR catalyst blocks from being subject to Section 301 pursuant to an exclusion issued by the Office of the United States Trade Representative (“USTR”).

In litigation, the government retreated from Customs’ original classification of the SCR catalyst blocks under HTS subheading 8421.39.40, instead arguing for a classification under HTS subheading 8421.39.80. Whereas HTS subheading 8421.39.40 provided for Other: Catalytic converters, HTS subheading 8421.39.80 provides for Centrifuges, including centrifugal dryers; filtering or purifying machinery and apparatus, for liquids or gases; parts thereof: Filtering or purifying machinery and apparatus for gases: Other: Other.

The Court reviewed this case pursuant to its jurisdiction under 28 U.S.C. § 1581(a) (2018). The Court concluded that neither party had asserted the correct classification. Rather, the Court found that the SCR catalyst blocks were properly classified under HTS subheading 8421.99.00 as parts of a gas filtering or purifying apparatus. The Court reasoned that the SCR catalyst blocks serve as a part under HTS heading 8421. The common meaning of “part” is a constituent member of a machine or other apparatus whereas “apparatus” is defined as “a set of materials or equipment designed for a particular use,” and in this case the SCR catalyst blocks at issue in this case are installed into larger SCR reactors that may contain hundreds of SCR catalyst blocks. The SCR catalyst blocks alone cannot process flue gas, as ammonia from the ammonia sprayer is needed to carry out the chemical reactions necessary to process the gas, thus the SCR catalyst blocks alone are not a material designed for a particular use per the definition of apparatus.

The Court then reasoned that the SCR system is a gas purifier under HTS 8421, even though Mitsubishi contended that the SCR catalyst blocks do not filter or purify gases because no matter is removed during catalytic conversion of NOx to harmless byproducts, and the government argued that the SCR catalyst blocks filter or purify flue gas because NOx is converted by the catalysts in the SCR catalyst blocks into nitrogen and water. The Court focused on the fact the SCR system works as a purifier, essentially freeing the flue gas from the undesirable and harmful Nox, and that both patent names involved in the SCR catalyst blocks highlight that the SCR system and blocks are involved in gas purification. The “essential character” of the goods’ components was not considered by the court,  given that General Rule of Interpretation (GRI) 1 resolved the classification issue presented.

The Court denied the parties motion and cross-motion for summary judgment and entered the order classifying the subject merchandise in HTS subheading 8421.99.00 and secondary heading 9903.88.01.