PMEP Home Page --> Pesticide Active Ingredient Information --> EXTOXNET: The Extension Toxicology Network --> Haloxyfop to Methyl Parathion --> Hydramethylnon

E  X  T  O  X  N  E  T
Extension Toxicology Network

A Pesticide Information Project of Cooperative Extension Offices of Cornell University, Michigan State University, Oregon State University, and University of California at Davis. Major support and funding was provided by the USDA/Extension Service/National Agricultural Pesticide Impact Assessment Program.


Publication Date: 9/93


Some trade names include ACJ217,300, Amdro and Maxforce.


Products containing hydramethylnon must bear the signal word "Caution" (1).


Hydramethylnon is an insecticide used in baits to control fire ants, leafcutter ants and cockroaches (1).


The toxicological properties of hydramethylnon have not been fully investigated (2).


Hydramethylnon is moderately toxic by ingestion and slightly toxic by dermal adsorption (2). It is not irritating to skin or eyes (2).

The oral LD50 for technical hydramethylnon in male rats is 1,131 mg/kg, and 1,300 mg/kg in female rats. The dermal LD50 on rabbits is > 5,000 mg/kg (1).


Chronic NOEL levels of 50 mg/kg for rats and 3 mg/kg for dogs have been reported (2).

Reproductive Effects

No information was found.

Teratogenic Effects

Hydramethylnon is non-teratogenic and non-embryotoxic in rats and rabbits (5).

Mutagenic Effects

Hydramethylnon is non-mutagenic (5).

Carcinogenic Effects

No information was found.

Organ Toxicity

No information was found.

Fate in Humans and Animals

In rats, following oral administration, hydramethylnon was rapidly eliminated in the feces and urine. No residues were detectable in the milk or tissues of goats (0.2 mg/kg in the daily diet for 8 days). No residues were found in the milk or tissues of cows (0.05 mg/kg for 21 consecutive days).


Effects on Birds

The oral LD50 for hydramethylnon in mallard ducks is > 2,510 mg/kg, and in bobwhite quail is 1,828 mg/kg (1).

Effects on Aquatic Organisms

Hydramethylnon is toxic to fish (4). The 96-hour LC50 for hydramethylnon in rainbow trout is 0.16 mg/l, 0.10 mg/l in channel catfish, and 1.70 mg/l in bluegill sunfish (1).

Hydramethylnon accumulated in bluegill sunfish at 1,300 times its concentration in surrounding waters (4).

Effects on Other Animals (Nontarget species)

Hydramethylnon is non-toxic to honey bees (5).


Breakdown of Chemical in Soil and Groundwater

Because hydramethylnon is only slightly soluble in water and has a very strong tendency to adsorb to soil particles, it is not mobile in soil and is unlikely to contaminate groundwater (3). When radio-labeled Amdro, a granular bait formulation, was applied to an aged soil column under laboratory conditions, 72% of the applied radioactivity remained in the treated soil after 45 days. Less than 0.2% of the radioactivity was recovered in leachate. This evidence supports the conclusion that neither Amdro nor its metabolites leach (4).

A soil half-life of 10 days has been reported (3). EPA reports a soil half-life of 18 hours, with breakdown probably due to decomposition by light and the rapid foraging of ants (4).

Breakdown of Chemical in Surface Water

No information was found.

Breakdown of Chemical in Vegetation

Over a 90-day rotation interval, hydramethylnon did not accumulate in crop plants planted after harvest of a treated crop (4). In another study, residues in grass 4 months after treatment were <0.01 ppm. Negligible residues were found in radishes, braley, and French beans planted 3 months after treatment of the soil (5).


Hydramethylnon is a yellow to orange solid. It is stable under normal temperatures and pressures, but may pose a slight fire hazard if exposed to heat or flame. It may burn, but does not ignite readily. It poses a fire and explosion hazard in the presence of strong oxidizers. Thermal decomposition of hydramethylnon may release highly toxic fumes of fluorides and oxides of nitrogen and carbon (2).

Exposure Guidelines:

No occupational exposure limits have been established for hydramethylnon by OSHA, NIOSH or ACGIH (2).

Physical Properties:

CAS #: 67485-29-4
Chemical name: Tetrahydro-5,5-dimethyl-2(1H)-pyrimidinone {3-{4-(trifluoromethyl) phenyl}-1-{2-{4-trifluoromethyl) phenyl} ethenyl}-2-propenyl-idene} hydrazone
Chemical Class/Use: pyrimidine hydrazone insecticide
H20 solubility: 5-7 ppb at 25 degrees C (1); 0.006 ug/ml (3)
Solubility in other solvents: soluble in acetone, chlorobenzene, hot ethyl acetate, and methylene chloride; slightly soluble in methanol, ethanol, and isopropanol (1).
Melting point: 365- 374 degrees F (185-190 degrees C) (2)
Vapor pressure: 2 x 10-8 mm Hg (3); negligible (2)
Koc: 1,000,000 (3)


American Cyanamid Co.
One Cyanamid Plaza
Wayne, NJ 07470
Emergency: 201-831-2000

Review by Basic Manufacturer:

Comments solicited: April, 1993
Comments received:


  1. Meister, R.T. (ed.). 1992. Farm Chemicals Handbook '92. Meister Publishing Company, Willoughby, OH.
  2. Occupational Health Services, Inc. 1992 (Nov. 17). MSDS for Hydramethylnon. OHS Inc., Secaucus, NJ.
  3. U. S. Department of Agriculture, Soil Conservation Service. 1990 (Nov.). SCS/ARS/CES Pesticide Properties Database: Version 2.0 (Summary). USDA - Soil Conservation Service, Syracuse, NY.
  4. US Environmental Protection Agency. March 19, 1992. Pesticide Environmental Fate One Line Summary: Hydramethylnon. Environmental Fate and Effects Division, US EPA, Washington, DC.
  5. The Agrochemical Handbook. 1991. The Royal Society of Chemistry. Cambridge, England.