Pesticide databaseHerbicidesChecked 2026-10-01

MCPA MCPA

Hormone-type (2,4-D, MCPA and others)Registered in JapanWHO IIApproved in the EUIARC 2B

Hormone-type (2,4-D, MCPA and others): Act like the plant growth hormone auxin, making broadleaf weeds grow abnormally until they die.

In Japan

Registration: Registered as a pesticide (first registered April 27, 1961). 12 formulated products contain it.
Main registered crops: trees and similar, Western lawn grass, Japanese lawn grass, paddy rice, barley, wheat and other small grains, trees and others (8 crop names in the registered uses)
Toxicity class: Active ingredient: MCPA isopropylamine salt: Ordinary / MCPA sodium salt: Ordinary
Classes of the 12 formulated products (diluted products sold): ordinary substance 12
Classes under Japan's Poisonous and Deleterious Substances Control Act.
ADI (acceptable daily intake): 0.0019 mg per kg of body weight per day
ARfD (acute reference dose): 0.32 mg per kg of body weight
Evaluation: Food Safety Commission of Japan, June 22, 2021

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 / 145	0.0%	0
Imported	0 / 1,874	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: II (Moderately hazardous), LD50 700 mg/kg
Based 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: 0.05 mg/kg bw/day; ARfD: 0.15 mg/kg bw
IARC (carcinogenicity): Group 2B (possibly carcinogenic to humans)
Chlorophenoxy herbicides: Vol. 41, Suppl. 7 (evaluated 1987)
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

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.

Pesticides registered in Japan are approved by the government with set crops, amounts, numbers of applications and days before harvest. This page lists facts stated in laws and in evaluations by public bodies; it does not judge whether anything is good or bad.

Other Hormone-type (2,4-D, MCPA and others)

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