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Dimethyl Methylphosphonate (DMMP) from China

DMMP is an organophosphorus compound used as a flame retardant additive and chemical intermediate in flameproof coatings and plastics. It falls under HTS 3824.99.93.61 because it consists mainly of chemicals containing a phosphorus atom bonded to one methyl group with no other carbon atoms directly attached beyond that. This specific mixture classification applies to its use in industrial chemical preparations.

Duty Rate — China → United States

42.5%

Rate breakdown

9903.88.0325%Except as provided in headings 9903.88.13, 9903.88.18, 9903.88.33, 9903.88.34, 9903.88.35, 9903.88.36, 9903.88.37, 9903.88.38, 9903.88.40, 9903.88.41, 9903.88.43, 9903.88.45, 9903.88.46, 9903.88.48, 9903.88.56, 9903.88.64, 9903.88.66, 9903.88.67, 9903.88.68, or 9903.88.69, articles the product of China, as provided for in U.S. note 20(e) to this subchapter and as provided for in the subheadings enumerated in U.S. note 20(f)
9903.05.3112.5%Section 301 (forced labor) — additional 12.5% ad valorem on products of China

Import Tips

Verify chemical purity and composition via lab analysis to confirm it meets the phosphorus-methyl bonding criteria for this subheading

Include Safety Data Sheets (SDS) and TSCA certification, as organophosphorus compounds may trigger EPA import notifications

Avoid misclassification as pesticide intermediates; ensure documentation specifies industrial chemical use to prevent delays