Food & Drink / Compounds / Ethephon (2-chloroethylphosphonic acid)

Ethephon (2-chloroethylphosphonic acid) in food: ingestion safety

Moderate risk

(People-specific data is limited; this page draws from human adult context.) EPA Toxicity Category II (moderately toxic). Corrosive to eyes and skin at concentrate. Oral LD50 ~4229 mg/kg in rats. Causes cholinesterase inhibition at high doses (not via classical organophosphate mechanism). Dietary residues on food crops generally well below tolerance levels. Primary concern: occupational exposure during mixing/application.

What is ethephon (2-chloroethylphosphonic acid)?

The IUPAC name is (2-chloroethyl)phosphonic acid.

Also known as: 2-Chloroethylphosphonic acid, Ethrel, Florel, Cepha.

IUPAC name
(2-chloroethyl)phosphonic acid
CAS number
16672-87-0
Molecular formula
C2H6ClO3P
Molecular weight
144.49 g/mol
SMILES
ClCCP(=O)(O)O
PubChem CID
27982

Risk for people

Moderate risk

EPA Toxicity Category II (moderately toxic). Corrosive to eyes and skin at concentrate. Oral LD50 ~4229 mg/kg in rats. Causes cholinesterase inhibition at high doses (not via classical organophosphate mechanism). Dietary residues on food crops generally well below tolerance levels. Primary concern: occupational exposure during mixing/application.

Regulatory consensus

3 regulatory and scientific bodies have classified Ethephon (2-chloroethylphosphonic acid). The classifications differ — that's the data.

AgencyYearClassificationNotes
EPA—Registered pesticide (plant growth regulator). Toxicity Category II (eye). Food tolerances established for numerous crops (40 CFR 180.300).
EU—Approved active substance (Reg. EC 1107/2009). MRL established for various crops.
Codex—Codex MRLs established for multiple commodities

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 you encounter ethephon (2-chloroethylphosphonic acid)

  • Agriculture — tomatoes (ripening), peppers (color development), cotton (defoliant/boll opening), tobacco (leaf curing), wheat/barley (lodging resistance)
  • Horticulture — ornamental flowering (ethylene release promotes blooming), pineapple (uniform flowering)
  • Food Residues — tomato products, pepper products, cereal grains

Safer alternatives

Lower-risk approaches that achieve a similar outcome to Ethephon (2-chloroethylphosphonic acid):

  • Ethylene gas (direct application)
    Trade-offs: Requires sealed ripening rooms. Not applicable for field use. Well-established technology for bananas, avocados.
  • 1-Methylcyclopropene (1-MCP / SmartFresh)
    Trade-offs: Used to delay rather than promote ripening. Post-harvest only. Very low toxicity.

Frequently asked questions

What products contain ethephon (2-chloroethylphosphonic acid)?

Ethephon (2-chloroethylphosphonic acid) appears in: tomatoes (ripening) (agriculture); peppers (color development) (agriculture); ornamental flowering (ethylene release promotes blooming) (horticulture); pineapple (uniform flowering) (horticulture); tomato products (food residues).

Why do regulators disagree about ethephon (2-chloroethylphosphonic acid)?

Ethephon (2-chloroethylphosphonic acid) has been classified by 3 agencies including EPA, EU, Codex, 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 Ethephon (2-chloroethylphosphonic acid) in the food app

Look up products containing ethephon (2-chloroethylphosphonic acid), compare to alternatives, and explore the full data record.

Open in food 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 →