EPA Designation Regulated
EPA Classification Organic Chemicals
EPA Levels 1,2 0.04 MCLG (mg/L)
0.04 MCLG (mg/L)
Alternative Names none
Sources Runoff/leaching from insecticide used on fruits, vegetables, alfalfa, livestock
Methoxychlor is an endocrine-disrupting insecticide similar to DDT; banned in the U.S. in 2002, it was historically used on farm animals and in animal feed, lumber, gardens and certain crops.


Methoxychlor is a colorless organic solid with a slightly fruity odor.


It is an insecticide preferred to DDT for use on animals, in animal feed, and on DDT-sensitive crops such as squash, melons, etc. Since methoxychlor is more unstable than DDT, it has less residual effect. It has been used extensively in Canada for the control of biting flies, and is also effective against mosquitoes and houseflies.

Health Effects

Some people who drink water containing methoxychlor well in excess of the maximum contaminant level (MCL) for many years could experience reproductive difficulties.

EPA Data Source: Methoxychlor

EPA Definitions:

1Maximum Contaminant Level Goal (MCLG) - The level of a contaminant in drinking water below which there is no known or expected risk to health. MCLGs allow for a margin of safety and are non-enforceable public health goals.

Maximum Contaminant Level (MCL) - The highest level of a contaminant that is allowed in drinking water. MCLs are set as close to MCLGs as feasible using the best available treatment technology and taking cost into consideration. MCLs are enforceable standards.

Maximum Residual Disinfectant Level Goal (MRDLG) - The level of a drinking water disinfectant below which there is no known or expected risk to health. MRDLGs do not reflect the benefits of the use of disinfectants to control microbial contaminants.

(TT) Treatment Technique - A required process intended to reduce the level of a contaminant in drinking water.

Maximum Residual Disinfectant Level (MRDL) - The highest level of a disinfectant allowed in drinking water. There is convincing evidence that addition of a disinfectant is necessary for control of microbial contaminants.

2 Units are in milligrams per liter (mg/L) unless otherwise noted. Milligrams per liter are equivalent to parts per million.