Perfluoroisobutene (PFIB) from Mexico
Perfluoroisobutene used as chemical intermediate despite high toxicity requiring special handling. HTS 2903.59.90.00 classification as branched unsaturated fluorinated acyclic hydrocarbon. Chapter 29 note (g) permits safety identification additives.
Duty Rate — Mexico → United States
100%
Rate breakdown
9903.04.6096.3%Pharmaceuticals Annex IV: patented pharma articles — 100% floor rate
9903.05.900%Articles already subject to Section 232 (steel/aluminum/copper + derivatives, autos + parts, wood, medium/heavy vehicles + parts, semiconductors, patented pharma) — U.S. note 52(f)
Import Tips
• Require DEA Schedule 1 chemical controls and end-user verification
• Use specialized PFIB-rated regulators with fluoropolymer diaphragms
• Include LC50 mammalian inhalation toxicity data (<0.02 ppm/4h)