HTS heading 2931 · Chapter 29
HTS 2931: Other organo-inorganic compounds
HTS heading 2931 covers other organo-inorganic compounds. It has 25 tariff lines with a duty rate; the general (MFN) rates are 3.7% (17 lines), 6.5% (5 lines), Free (2 lines) and others.
Imports may also owe Chapter 99 tariffs (Section 232, 301 or 201) depending on origin and date, plus the Merchandise Processing Fee and, by sea, the Harbor Maintenance Fee.
Rates from the 2026 HTS Revision 22, effective October 30, 2026. Source: U.S. International Trade Commission.
Tariff lines and duty rates
| HTS code | Description | General | Special | Column 2 | Estimate |
|---|---|---|---|---|---|
| 2931.10.00.00 | Tetramethyl lead and tetraethyl lead[kg] | 3.7% | Free (A,AU,BH,CL,CO,D,E,IL,JO,KR,MA,OM,P,PA,PE,S,SG) | 25% | Estimate → |
| 2931.20.00.00 | Tributyltin compounds[kg] | 3.7% | Free (A,AU,BH,CL,CO,D,E,IL,JO,KR,MA,OM,P,PA,PE,S,SG) | 25% | Estimate → |
| Non-halogenated organo-phosphorous derivatives: | |||||
| 2931.41.00.00 | Dimethyl methylphosphonate[kg] | 3.7% | Free (A,AU,BH,CL,CO,D,E,IL,JO,K,KR,MA,OM,P,PA,PE,S,SG) | 25% | Estimate → |
| 2931.42.00.00 | Dimethyl propylphosphonate[kg] | 3.7% | Free (A,AU,BH,CL,CO,D,E,IL,JO,K,KR,MA,OM,P,PA,PE,S,SG) | 25% | Estimate → |
| 2931.43.00.00 | Diethyl ethylphosphonate[kg] | 3.7% | Free (A,AU,BH,CL,CO,D,E,IL,JO,K,KR,MA,OM,P,PA,PE,S,SG) | 25% | Estimate → |
| 2931.44.00.00 | Methylphosphonic acid[kg] | 3.7% | Free (A,AU,BH,CL,CO,D,E,IL,JO,K,KR,MA,OM,P,PA,PE,S,SG) | 25% | Estimate → |
| 2931.45.00.00 | Salt of methylphosphonic acid and (aminoiminomethyl)urea (1:1)[kg] | 3.7% | Free (A,AU,BH,CL,CO,D,E,IL,JO,K,KR,MA,OM,P,PA,PE,S,SG) | 25% | Estimate → |
| 2931.46.00.00 | 2,4,6-Tripropyl-1,3,5,2,4,6-trioxatriphosphinane 2,4,6-trioxide[kg] | 3.7% | Free (A,AU,BH,CL,CO,D,E,IL,JO,K,KR,MA,OM,P,PA,PE,S,SG) | 25% | Estimate → |
| 2931.47.00.00 | (5-Ethyl-2-methyl-2-oxido-1,3,2-dioxaphosphinan-5-yl) methyl methyl methylphosphonate[kg] | 3.7% | Free (A,AU,BH,CL,CO,D,E,IL,JO,K,KR,MA,OM,P,PA,PE,S,SG) | 25% | Estimate → |
| 2931.48.00.00 | 3,9-Dimethyl-2,4,8,10-tetraoxa-3,9-diphosphaspiro [5.5] undecane 3,9-dioxide[kg] | 3.7% | Free (A,AU,BH,CL,CO,D,E,IL,JO,K,KR,MA,OM,P,PA,PE,S,SG) | 25% | Estimate → |
| 2931.49.00 | Other | 3.7% | Free (A,AU,BH,CL,CO,D,E,IL,JO,K,KR,MA,OM,P,PA,PE,S,SG) | 25% | |
| 2931.49.00.05 | O-Alkyl (≤C10, including cycloalkyl) N,N-dialkyl (methyl, ethyl, n-propyl or isopropyl) phosphoramidocyanidates[kg] | Estimate → | |||
| 2931.49.00.08 | [O-2-(Dialkyl (methyl, ethyl, n-propyl or isopropyl) amino)ethyl] hydrogen alkyl (methyl, ethyl, n-propyl or isopropyl) phosphonites and their O-alkyl (≤C10, including cycloalkyl) esters; alkylated or protonated salts thereof[kg] | Estimate → | |||
| 2931.49.00.10 | 2-Amino-4-[hydroxy(methyl)phosphonoyl] butanoic acid (glufosinate) and its salts and esters[kg] | Estimate → | |||
| 2931.49.00.15 | Butyl methylphosphinate[kg] | Estimate → | |||
| 2931.49.00.20 | N-(Phosphonomethyl) glycine (glyphosate) and its salts and esters[kg] | Estimate → | |||
| 2931.49.00.25 | Bis(1-methylpentyl) methylphosphonate[kg] | Estimate → | |||
| Other: | |||||
| 2931.49.00.55 | Containing a phosphorus atom to which one methyl, ethyl, n-propyl or isopropyl group is bonded but no further carbon atoms[kg] | Estimate → | |||
| 2931.49.00.80 | Other[kg] | Estimate → | |||
| Halogenated organo-phosphorous derivatives: | |||||
| 2931.51.00.00 | Methylphosphonic dichloride[kg] | 3.7% | Free (A,AU,BH,CL,CO,D,E,IL,JO,K,KR,MA,OM,P,PA,PE,S,SG) | 25% | Estimate → |
| 2931.52.00.00 | Propylphosphonic dichloride[kg] | 3.7% | Free (A,AU,BH,CL,CO,D,E,IL,JO,K,KR,MA,OM,P,PA,PE,S,SG) | 25% | Estimate → |
| 2931.53.00.00 | O-(3-chloropropyl) O-[4-nitro-3-(trifluoromethyl)phenyl] methylphosphonothionate[kg] | 3.7% | Free (A,AU,BH,CL,CO,D,E,IL,JO,K,KR,MA,OM,P,PA,PE,S,SG) | 25% | Estimate → |
| 2931.54.00.00 | Trichlorfon (ISO)[kg] | 3.7% | Free (A,AU,BH,CL,CO,D,E,IL,JO,K,KR,MA,OM,P,PA,PE,S,SG) | 25% | Estimate → |
| 2931.59.00 | Other | 3.7% | Free (A,AU,BH,CL,CO,D,E,IL,JO,K,KR,MA,OM,P,PA,PE,S,SG) | 25% | |
| 2931.59.00.10 | O-Alkyl (≤ C10, including cycloalkyl) alkyl (methyl, ethyl,n- propyl or isopropyl) phosphonofluoridates[kg] | Estimate → | |||
| 2931.59.00.15 | Alkyl (methyl, ethyl, n-propyl or isopropyl) phosphonyl difluorides[kg] | Estimate → | |||
| 2931.59.00.20 | O-Isopropyl methylphosphonochloridate[kg] | Estimate → | |||
| 2931.59.00.25 | O-Pinacolyl methylphosphonochloridate[kg] | Estimate → | |||
| 2931.59.00.30 | P-Alkyl (≤ C10, incl. cycloalkyl) N-(1-(dialkyl (≤ C10, incl. cycloalkyl) amino))alkylidene (H or ≤C10, incl. cycloalkyl) phosphonamidic fluorides and corresponding alkylated or protonated salts[kg] | Estimate → | |||
| 2931.59.00.35 | Methyl- bis(diethylamino)methylene)phosphonamidofluoridate[kg] | Estimate → | |||
| 2931.59.00.60 | Containing a phosphorus atom to which one methyl, ethyl, n-propyl or isopropyl group is bonded but no further carbon atoms[kg] | Estimate → | |||
| 2931.59.00.80 | Other[kg] | Estimate → | |||
| 2931.90 | Other: | ||||
| Aromatic: | |||||
| 2931.90.05.00 | Diphenyldichlorosilane; and phenyltrichlorosilane[kg] | Free | 15.4¢/kg + 68.5% | Estimate → | |
| 2931.90.10.00 | 4,4'-Diphenylbisphosphonous acid, di(2',2",4',4"-di-tert-butyl)phenyl ester[kg] | 6.5% | Free (A+, AU, BH, CL,CO,D, E, IL, JO, KR, MA, OM, P, PA, PE, S, SG) | 15.4¢/kg + 40% | Estimate → |
| 2931.90.15.00 | Sodium tetraphenylboron[kg] | 5.8% | Free (A+, AU, BH, CL, CO, D, E, IL, JO, KR, MA, OM, P, PA, PE, S, SG) | 15.4¢/kg + 40% | Estimate → |
| Other: | |||||
| 2931.90.22.00 | Drugs[kg] | 6.5% | Free (A+,AU,BH,CL,CO,D, E,IL,JO,K, KR,MA,OM,P, PA,PE,S,SG) | 15.4¢/kg + 67.5% | Estimate → |
| 2931.90.26.00 | Pesticides[kg] | 6.5% | Free (A*,AU,BH,CL,CO,D,E,IL,JO,KR,MA,OM,P,PA,PE,S,SG) | 15.4¢/kg + 40% | Estimate → |
| Other: | |||||
| 2931.90.30.00 | Products described in additional U.S. note 3 to section VI[kg] | 6.5% | Free (A+,AU,BH,CL,CO,D, E,IL,JO,K, KR,MA,OM,P, PA,PE,S,SG) | 15.4¢/kg + 68.5% | Estimate → |
| 2931.90.60.00 | Other[kg] | 6.5% | Free (A+,AU,BH,CL,CO,D, E,IL,JO,K, KR,MA,OM,P, PA,PE,S,SG) | 15.4¢/kg + 68.5% | Estimate → |
| Other: | |||||
| 2931.90.70.00 | N,N'-Bis(trimethylsilyl) urea; 3-(Hydroxymethylphosphinyl)-1-propanoic acid, 2-hydroxyethyl ester; and 2-Phosphonobutane-1,2,4-tricarboxylic acid and its salts[kg] | Free | 25% | Estimate → | |
| 2931.90.90 | Other | 3.7% | Free (A*,AU,BH,CL,CO,D,E,IL,JO,K,KR,MA,OM,P,PA,PE,S,SG) | 25% | |
| 2931.90.90.10 | Organo-silicon compounds[kg] | Estimate → | |||
| Organo-tin compounds: | |||||
| 2931.90.90.21 | Dibutyltin oxide[kg] | Estimate → | |||
| 2931.90.90.25 | Tetrabutyltin[kg] | Estimate → | |||
| 2931.90.90.29 | Other[kg] | Estimate → | |||
| 2931.90.90.30 | 2-Chlorovinyldichloroarsine[kg] | Estimate → | |||
| 2931.90.90.35 | Bis(2-chlorovinyl)chloroarsine[kg] | Estimate → | |||
| 2931.90.90.40 | Tris(2-chlorovinyl)arsine[kg] | Estimate → | |||
| 2931.90.90.52 | Other[kg] | Estimate → |
49 lines shown. Statistical suffixes (the last two digits) inherit the rate of the 8-digit subheading above them.
Example: base duty and fees on $10000
For HTS 2931.10.00.00 at the general rate of 3.7%, shipped by ocean, before any Chapter 99 tariffs:
| Base duty (3.7%) | $370.00 |
| Merchandise Processing Fee (0.3464%, min $34.58) | $34.64 |
| Harbor Maintenance Fee (0.125%) | $12.50 |
| Duty and fees | $417.14 |
Origin-specific tariffs can multiply this. Run this example from China or from Mexico to see every line.
Special program codes in this heading
- A, A*, A+
- Generalized System of Preferences (GSP)
- AU
- U.S.–Australia FTA
- BH
- U.S.–Bahrain FTA
- CL
- U.S.–Chile FTA
- CO
- U.S.–Colombia Trade Promotion Agreement
- D
- African Growth and Opportunity Act (AGOA)
- E, E*
- Caribbean Basin Economic Recovery Act
- IL
- U.S.–Israel FTA
- JO
- U.S.–Jordan FTA
- K
- Agreement on Trade in Pharmaceutical Products
- KR
- U.S.–Korea FTA (KORUS)
- MA
- U.S.–Morocco FTA
- OM
- U.S.–Oman FTA
- P, P+
- CAFTA-DR
- PA
- U.S.–Panama Trade Promotion Agreement
- PE
- U.S.–Peru Trade Promotion Agreement
- S, S+
- USMCA (United States–Mexico–Canada Agreement)
- SG
- U.S.–Singapore FTA
A special rate applies only when the goods qualify under that program's rules of origin and the claim is made at entry.
Frequently asked questions
What is the duty rate for HTS 2931?
Heading 2931 has 25 rate lines. The general (MFN) duty rates are 3.7% (17 lines), 6.5% (5 lines), Free (2 lines), 5.8% (1 line). Products of free trade agreement partners may enter at the special rate, and Column 2 rates apply to countries without normal trade relations. Chapter 99 tariffs can be added on top: calculate the full amount.
Do Section 301, 232 or 201 tariffs apply to HTS 2931?
It depends on the 8- or 10-digit subheading, the country of origin, the entry date and, for Section 232, the metal content. These additional duties are listed in Chapter 99 of the HTS. The free duty calculator checks each program for a given code, origin and date and shows which apply and why.
What fees are added to an import under HTS 2931?
Formal entries pay the Merchandise Processing Fee of 0.3464% of value (minimum $34.58, maximum $670.86 in FY2027). Ocean shipments also pay the Harbor Maintenance Fee of 0.125% of value. See the import duty calculator for how they combine.