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Sulfur trioxide

CAS 7446-11-9

U.S. production volumes are classified as confidential business information.

Molecular structure of 7446-11-9
US productionCBI
Import value, 2024$75M
Top sourceChina 30%

At least one company claimed its 2023 production or import volume for this chemical as confidential, so EPA withholds it.

Why supply is unknown

Production is reported production, not a complete census of factories. US production volume is confidential. Production reporting year: 2023. Import value and source-country shares describe a shared customs category, not a separate chemical measurement.

Where It Comes From

Customs basis: HS 281129 · basket

EPA reports by year
2023
US production Confidential · Imports Confidential
2019
US production Confidential · Imports Confidential

These shares come from HS customs code 281129, which covers 18 tracked chemicals in total. They estimate the category's origin mix, not this chemical specifically.

Source Countries
CN 30%ChinaAT 23%AustriaPL 9%PolandCA 8%CanadaCZ 8%Czech Republic
EPA-registered manufacturers (6)
Advansix
Cornerstone Chemical
Duke Energy
Ecovyst
Steel Dust Recycling
Show all 6
Wsp
Domestic parents -- activity not disclosed (1)
Veolia Regeneration Services

Why It Matters

Sectors
DefenseAgricultureEnergyWaterConstructionMetals & MiningPlastics & RubberConsumer ProductsCore Chemicals
Downstream UsesNot recorded
FDA Shortage Status
No FDA shortage records

Industrial Uses

Used in 13 sectors as 5 functional roles.

  • •Intermediate in All Other Basic Organic Chemical Manufacturing (100%)Processing as a reactant
  • •Intermediate in Utilities (100%)Processing as a reactant
  • •Intermediate in Explosives Manufacturing (5%)Processing as a reactant
  • •Conductive agent in Utilities (100%)Processing as a reactant
  • •Intermediate in Agriculture, Forestry, Fishing and Hunting (10%)Processing—incorporation into formulation, mixture, or reaction product
  • •Processing aids, specific to petroleum production in Petroleum Refineries (20%)Processing—incorporation into formulation, mixture, or reaction product
  • •Intermediate in Cyclic Crude and Intermediate Manufacturing (60%)Processing—incorporation into formulation, mixture, or reaction product
  • •Agricultural chemicals (non-pesticidal) in Pesticide, Fertilizer, and Other Agricultural Chemical Manufacturing (5%)Processing—incorporation into formulation, mixture, or reaction product
  • •Process regulators in All Other Chemical Product and Preparation Manufacturing (5%)Processing—incorporation into formulation, mixture, or reaction product
  • •Intermediate in All Other Basic Inorganic Chemical Manufacturing (40%)Processing—incorporation into formulation, mixture, or reaction product
  • •Intermediate in Primary Metal Manufacturing (4%)Processing—incorporation into formulation, mixture, or reaction product
  • •Intermediate in All other Petroleum and Coal Products Manufacturing (10%)Processing as a reactant
  • •Intermediate in Plastics Material and Resin Manufacturing (10%)Processing as a reactant
  • •Intermediate in Soap, Cleaning Compound, and Toilet Preparation Manufacturing (40%)Processing as a reactant
  • •Process regulators in Petroleum Refineries (2%)Processing as a reactant

Chemical Identity

CAS7446-11-9
PubChem CID24682
DTXSIDDTXSID1029673
FormulaO3S
Mol. Weight80.07 g/mol
SMILESO=S(=O)=O

Data Sources

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Brief citations

Sulfur trioxide (CAS 7446-11-9) https://chemicalindependence.com/chemical/7446-11-9/ EPA CompTox (DSSTox): DTXSID1029673. Retrieved 2026-04-06. https://comptox.epa.gov/dashboard/chemical/details/DTXSID1029673 PubChem: 24682. Retrieved 2026-04-06. https://pubchem.ncbi.nlm.nih.gov/compound/24682 EPA Chemical Data Reporting: 7446-11-9. Reporting year: 2023. https://www.epa.gov/chemical-data-reporting EPA Chemical Data Reporting: CAS 7446-11-9. Reporting year: 2019. https://www.epa.gov/chemical-data-reporting US Census international trade: HS 281129 for CAS 7446-11-9. Reporting year: 2024. https://usatrade.census.gov/