Parathion パラチオン
Also known in Japanese as ホリドール
Organophosphates: Block the action of the enzyme that stops nerve signals (acetylcholinesterase). Used for a long time.
In Japan
- Registration
- Its registration as a pesticide expired on December 31, 1969 (first registered January 24, 1952). It can no longer be used as a pesticide in Japan.
- ADI (acceptable daily intake)
- No risk assessment report by the Food Safety Commission of Japan was found
ADI: the amount considered to have no effect on health even if eaten every day for a lifetime. ARfD: the amount considered to have no effect on health when eaten at one time (within 24 hours). Both are set by the Food Safety Commission of Japan, mainly from animal studies.
In Japan's national residue testing (fiscal 2024)
| Produce | Detected / tested | Detection rate | Over the limit |
|---|---|---|---|
| Domestic | 0 / 4,155 | 0.0% | 0 |
| Imported | 0 / 1,146 | 0.0% | 0 |
Tests are counted as pesticide × sample. Any detection counts as “detected” — it does not mean the limit was exceeded. For pesticides outside the top 20, figures are summed from the food-by-food tables of the full report.
Evaluations abroad
- WHO acute toxicity class
- Ia (Extremely hazardous), LD50 13 mg/kgBased on the toxicity of the undiluted active ingredient given once, mainly to rats by mouth (LD50 = the dose that kills half; the smaller, the stronger the acute toxicity). It is not an assessment of the safety of residues in food.
- EU
- Not approved in the EUEU ADI: 0.0006 mg/kg bw/day; ARfD: 0.005 mg/kg bw
- IARC (carcinogenicity)
- Group 2B (possibly carcinogenic to humans)Parathion: Vol. 30, Suppl. 7, 112 (evaluated 2015)IARC classifications rate the strength of evidence that something can cause cancer, not the size of the risk at the amounts eaten in food.
Good to know
- Because of its strong acute toxicity and the many poisoning accidents during use, its registration expired in Japan in 1969.
Related explainers
Sources
- FAMIC (Food and Agricultural Materials Inspection Center), pesticide registration information (as of Sept. 30, 2026) (Japanese)
- MHLW, results of pesticide residue testing in foods, fiscal 2024 (Japanese)
- WHO Recommended Classification of Pesticides by Hazard 2019
- EU Pesticides Database (Parathion)
- IARC (International Agency for Research on Cancer) List of Classifications
Last checked 2026-10-01. Registrations and evaluations change over time. This page is a translation of our Japanese page; if they differ, the Japanese page is the reference.