Malathion マラチオン
Also known in Japanese as マラソン
Organophosphates: Block the action of the enzyme that stops nerve signals (acetylcholinesterase). Used for a long time.
In Japan
- Registration
- Registered as a pesticide (first registered February 7, 1953). 10 formulated products contain it.
- Main registered crops
- eggplant, cabbage, broccoli, napa cabbage, daikon radish, lettuce and others (52 crop names in the registered uses)
- Toxicity class
- Active ingredient: Ordinary substanceClasses of the 10 formulated products (diluted products sold): ordinary substance 6, deleterious substance 4Classes under Japan's Poisonous and Deleterious Substances Control Act.
- ADI (acceptable daily intake)
- 0.29 mg per kg of body weight per day
- ARfD (acute reference dose)
- 1.5 mg per kg of body weight
- Evaluation
- Food Safety Commission of Japan, May 13, 2014
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 | 3 / 5,276 | 0.1% | 0 |
| Imported | 69 / 5,418 | 1.3% | 0 |
Found in domestic foods: spinach, asparagus, soybean (max. 0.3 ppm)
Found in imported foods: cherry (including cherries), other citrus fruits, other grains, corn (maize), grape, peanut, avocado, orange (including navel orange), grapefruit, celery, blueberry, lime and others (max. 0.4 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
- III (Slightly hazardous), LD50 c2100 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
- Approved in the EU (approval expires July 2028)EU ADI: 0.03 mg/kg bw/day; ARfD: 0.3 mg/kg bw
- IARC (carcinogenicity)
- Group 2A (probably carcinogenic to humans)Malathion: 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.
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 Malathion (May 13, 2014) (Japanese)
- MHLW, results of pesticide residue testing in foods, fiscal 2024 (Japanese)
- WHO Recommended Classification of Pesticides by Hazard 2019
- EU Pesticides Database (Malathion)
- 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.