Outdoor & Yard / Compounds / R-1234yf (2,3,3,3-Tetrafluoropropene)

R-1234yf (2,3,3,3-Tetrafluoropropene) in the yard and garden

Low risk for your yard

Low toxicity at normal exposure levels. Primary risk is decomposition products (HF) during fire or leak near ignition source. A2L flammability rating — mildly flammable but difficult to ignite under normal conditions.

What is r-1234yf (2,3,3,3-tetrafluoropropene)?

Also known as: 5-chloro-4-cyanoacetyl-1-methyl-3-trifluoromethylpyrazole, SCHEMBL6740735.

CAS number
29118-24-9
Molecular formula
C3H2F4
Molecular weight
114.04 g/mol
SMILES
CN1C(=C(C(=N1)C(F)(F)F)C(=O)CC#N)Cl
PubChem CID
9856345

Risk for people, pets,

Low risk

Low toxicity at normal exposure levels. Primary risk is decomposition products (HF) during fire or leak near ignition source. A2L flammability rating — mildly flammable but difficult to ignite under normal conditions.

Regulatory consensus

5 regulatory and scientific bodies have classified R-1234yf (2,3,3,3-Tetrafluoropropene). The classifications differ — that's the data.

AgencyYearClassificationNotes
EU MAC DIRECTIVE—Mandated replacement for R-134a in mobile AC (GWP<150 required since 2017)
EPA SNAP—Listed as acceptable substitute for R-134a in motor vehicle AC (SNAP Rule 21)
UN F GAS—Exempt from EU F-gas regulation phase-down (GWP<150)
ASHRAE 34—Safety classification A2L (lower toxicity, lower flammability)
DOT HAZMAT—UN2517, Flammable gas, Class 2.1

Regulators apply different standards of evidence — animal-data weighting, exposure-pattern assumptions, epidemiological power thresholds — which is why two scientific bodies can review the same data and reach different conclusions. The disagreement is the data.

Where your yard encounter r-1234yf (2,3,3,3-tetrafluoropropene)

  • Automotive Ac — Standard refrigerant in all new passenger vehicles (EU mandate since 2017, US adoption widespread)
  • Heat Pumps — Emerging use in residential heat pump systems
  • Commercial Refrigeration — Low-charge commercial refrigeration units
  • Aerosol Propellant — Specialty aerosol applications replacing HFC-134a

Safer alternatives

Lower-risk approaches that achieve a similar outcome to R-1234yf (2,3,3,3-Tetrafluoropropene):

  • R-744 (CO2)
    Trade-offs: Removes 95-99% of dissolved contaminants including metals, PFAS, nitrates; wastes 2-4 gallons per gallon produced (improving with newer systems); removes beneficial minerals; $0.05-0.25/gallon; requires pre-treatment for longevity.
    Relative cost: 1.2-2×
  • R-290 (Propane)
    Trade-offs: Removes 95-99% of dissolved contaminants including metals, PFAS, nitrates; wastes 2-4 gallons per gallon produced (improving with newer systems); removes beneficial minerals; $0.05-0.25/gallon; requires pre-treatment for longevity.
    Relative cost: 1.2-2×

Frequently asked questions

Is r-1234yf (2,3,3,3-tetrafluoropropene) safe for your yard?

Low toxicity at normal exposure levels. Primary risk is decomposition products (HF) during fire or leak near ignition source. A2L flammability rating — mildly flammable but difficult to ignite under normal conditions.

What products contain r-1234yf (2,3,3,3-tetrafluoropropene)?

R-1234yf (2,3,3,3-Tetrafluoropropene) appears in: Standard refrigerant in all new passenger vehicles (EU mandate since 2017, US adoption widespread) (Automotive Ac); Emerging use in residential heat pump systems (Heat Pumps); Low-charge commercial refrigeration units (Commercial Refrigeration).

Why do regulators disagree about r-1234yf (2,3,3,3-tetrafluoropropene)?

R-1234yf (2,3,3,3-Tetrafluoropropene) has been classified by 5 agencies including EU MAC DIRECTIVE, EPA SNAP, UN F GAS, ASHRAE 34, DOT HAZMAT, with differing conclusions. Regulators apply different standards of evidence (animal data weighting, exposure-pattern assumptions, epidemiological power thresholds), which is why two scientific bodies can review the same data and reach different conclusions. See the regulatory consensus table on this page for the full picture.

See R-1234yf (2,3,3,3-Tetrafluoropropene) in the outdoor app

Look up products containing r-1234yf (2,3,3,3-tetrafluoropropene), compare to alternatives, and explore the full data record.

Open in outdoor View raw API data

Sources (1)
  1. — expert_curation

Reference data, not professional advice. Aggregates publicly available regulatory and scientific data; not a substitute for veterinary, medical, legal, or regulatory advice. Why we built ALETHEIA →