Isopropyl Methylphosphonic Acid (IMPA) from Canada
IMPA contains a phosphorus atom bonded to one methyl group and one isopropoxy group (P-CH3, P-O-CH(CH3)2). Fits HTS 2931.49.0055 as the phosphorus has one isopropyl group allowed by the heading description with no further carbon atoms in the chain. Marker compound for chemical weapons verification.
Duty Rate — Canada → 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
9903.05.2910%Except for products described in headings 9903.05.85–9903.05.93, articles the product of Canada, as provided for in U.S. note 52 to this subchapter
Import Tips
• Include OPCW or laboratory certification for legitimate analytical use to avoid security delays
• Test for impurities that could trigger reclassification to pesticide headings (3808)
• Store and ship as corrosive solid; verify temperature control for stability