Chlorothalonil TPN（クロロタロニル）
Also known in Japanese as TPN
Multi-site fungicides: Act on many sites in fungal cells. Resistance is slow to develop (mancozeb, TPN, captan and others).
In Japan
- Registration
- Registered as a pesticide (first registered June 23, 1965). 42 formulated products contain it.
- Main registered crops
- tomato, cucumber, napa cabbage, onion, watermelon, eggplant and others (93 crop names in the registered uses)
- Toxicity class
- Active ingredient: Ordinary substanceClasses of the 42 formulated products (diluted products sold): ordinary substance 42Classes under Japan's Poisonous and Deleterious Substances Control Act.
- ADI (acceptable daily intake)
- 0.018 mg per kg of body weight per day
- ARfD (acute reference dose)
- 0.6 mg per kg of body weight
- Evaluation
- Food Safety Commission of Japan, June 23, 2026
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 / 92 | 0.0% | 0 |
| Imported | 3 / 65 | 4.6% | 0 |
Found in imported foods: okra, tomato (max. 0.85 ppm)
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
- U (Unlikely to present acute hazard in normal use), LD50 >10000 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 EU (approval ended May 2019)EU ADI: 0.015 mg/kg bw/day; ARfD: 0.05 mg/kg bw
- IARC (carcinogenicity)
- Group 2B (possibly carcinogenic to humans)Chlorothalonil: Vol. Suppl. 7, 73 (evaluated 1998)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
- In 2019, the EU did not renew its approval because of concerns such as breakdown products remaining in groundwater.
Related explainers
Sources
- FAMIC (Food and Agricultural Materials Inspection Center), pesticide registration information (as of Sept. 30, 2026) (Japanese)
- Food Safety Commission of Japan, risk assessment report on Chlorothalonil (June 23, 2026) (Japanese)
- MHLW, results of pesticide residue testing in foods, fiscal 2024 (Japanese)
- WHO Recommended Classification of Pesticides by Hazard 2019
- EU Pesticides Database (Chlorothalonil)
- 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.