Agent Name

Maleic hydrazide

CAS Number




Major Category



2,3,6-Tetrahydro-3,6-dioxopyridazine; 1,2-Dihydro-3,6-pyradizinedione; 1,2-Dihydropyridazine-3,6-dione; 3(2H)-Pyridazinone, 6-hydroxy-; 3,6-Dihydroxypyridazine; 3,6-Dioxopyridazine; 3,6-Pyridazinediol; 3,6-Pyridazinedione, 1,2-dihydro-; 6-Hydroxy-2H-pyridazin-3-one; 6-Hydroxy-3(2H)-pyridazinone; Antergon; Antyrost; Burtolin; Chemform; De-cut; De-sprout; Drexel-super P; Fair 30; Fair PS; Fair plus; Fair-2; Fazor; Gotax; Hydrazid kyseliny maleinove [Czech]; Hydrazide maleique; Hydrazide maleique [ISO-French]; KMH; MAH; MG-T; MH; MH 30; MH 36 bayer; MH-40; Maintain 3; Malazide; Maleic acid cyclic hydrazide; Maleic acid hydrazide; Maleic hydrazide; Maleic hydrazine; Malein 30; Maleinsaeurehydrazid [German]; Malzid; Mazide; Milurit; N,N-Maleoylhydrazine; Regulox; Regulox 36; Regulox 50 W; Regulox W; Retard; Royal MH-30; Royal slo-gro; Slo-Gro; Sprout-stop; Sprout/off; Stuntman; Sucker-stuff; Super de-sprout; Super sprout stop; Super sucker-stuff; Super sucker-stuff HC; Super-de-sprout; Unriprim; Vondalhyde; Vondrax; [ChemIDplus]


Plant Growth Regulators


Colorless, crystalline solid; [HSDB] White solid; Formulated as emulsifiable concentrate and soluble concentrate (liquid and solid); [Reference #1]


Used as a herbicide and plant growth inhibitor, e.g., to control sucker growth on tobacco and to inhibit sprouting of potatoes and onions; [HSDB] A plant growth regulator and herbicide used to control sprouting of potatoes and onions, suckers in tobacco, and weeds, grasses, and trees in and along turf, ornamentals, public easements, and industrial and commercial land; [Reference #1]


Maleic hydrazide "may be hepatotoxic on ingestion." [Zimmerman, p. 393] The technical product is required to have no more than 15 ppm hydrazine contamination; The potassium salt (CAS# 28382-15-2) is also registered for use in the US; [Reference #1]

Reference Link

EPA Pesticide Chemical Search

Exposure Assessment
Vapor Pressure

2.77E-6 mm Hg

Lethal Concentration

LC50 (rat) >20,000 mg/m3

Adverse Effects

Hepatotoxin, Secondary

IARC Carcinogen

Not Classifiable

Links to Other NLM Databases
Health Studies

Human Health Effects from Hazardous Substances Data Bank:

Toxicity Information


Chemical Information

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Related Information in HazMap

Industrial Processes with risk of exposure: