Odorant

Basics

• A Chemical used to add a scent to various Compressed Gasses (Typically Methane or Propane / LPG )
• Thus when there is a leak one can detect the smell and respond accordingly
• Various Compounds Are Used, but the main ones are:
  • Methanethiol (Common in Methane (aka "Natural Gas" ; CNG ) )
  • Ethanethiol (Common in Propane / LPG )
    • The Following can also be used (or blended with eachother and/or the odorants listed above)
      • Dimethyl Sulfide
      • Isopropyl Mercaptan (aka Isopropanethiol )
      • Methyl Ethyl Sulfide
      • Normal Propyl Mercaptan (aka Propanethiol )
      • Secondary Butyl Mercaptan (aka 2-Butanethiol )
      • Tertiary Butyl Mercaptan (aka tert-Butylthiol )
      • Tetrahydrothiophene

Types

Conventional Sulfur Compounds

• ” Sulfur Mercaptan “

Novel Sulfur Compounds

• ”Grapefruit Mercaptan”
  • A Listing by High Precision Gas for this Odorant

Novel Sulfur Free Odorants

Why

• Main advantage is the lack of Sulfur Dioxide emissions, thus no Sulfur Pollution / Acid Rain Risks
• Also thus makes propane EVEN CLEANER burning
• Main downsides are cost/low TRL
  • Also may mot be widely known by the community/may smell different
• May have less Odorant Fade issues
• Granted CITATION NEEDED, but may be less harmful to health (Especially chronic exposure from Warehouse Forklifts or at a Filling Station etc)

What Exists on the Market

Aygaz “GreenOdor”

• Currently the “GreenOdor Project” ; uncertain on Technology Readiness Level
• As stated in a Stock Shareholder Presentation, “aiming to prevent 40 tons of sulfur emission per year”
• A Türkish Company
• Mentioned on Page 34 of Their August 2025 Investor Presentation

Internal Links

• Odorizer (The device used for Gas Odorization )

External Links

• The Wikipedia Page on "Aroma Compounds" Which is a Multi-Topic Page Including Odorants
• A Page by the Company "GPL Odorizers" Titled "What are the Odorants used in Natural Gas to make it Detectable?"
• A Page by the Company "GPL Odorizers" Titled "What is natural gas odorization?"
• The Science Direct Overview Page on Gas Odorization
• A Page by "GDS Corp" Titled "Mercaptan: The Chemical Behind Natural Gas Additives"
• A 1987 USA CPSC Report Titled "Information on LP-Gas (Propane) Odorant, part 1"