Ethyl Methylphosphonic Acid (EMPA) from Mexico
EMPA (CH3P(O)(OH)(OC2H5)) is a hydrolysis product of nerve agents, containing a phosphorus atom bonded to one methyl group, one ethoxy group, and one hydroxyl. Classified under HTS 2931.49.0055 due to the single methyl group on phosphorus with no additional carbon atoms beyond the ethyl substituent. Used in chemical analysis standards and decontamination studies.
Duty Rate — Mexico → United States
110%
Rate breakdown
9903.04.6096.3%Except as provided in heading 9903.04.61, patented pharmaceutical articles as provided for in subdivisions (c) and (d) of U.S. note 40 to this subchapter
9903.05.5510%Except for products described in headings 9903.05.85–9903.05.92 and 9903.05.94, articles the product of Mexico, as provided for in U.S. note 52 to this subchapter
Import Tips
• Submit certificates of analysis proving EMPA purity (>98%) and structural confirmation via mass spectrometry
• Declare any military or CBRN-related end-uses immediately; may require State Department or BIS licenses