Liver and kidney damage are likely after long-term exposure. High doses may produce anemia because of the formation of methemoglobin. In a 2-year feeding study with rats, high doses of propanil caused a decrease in growth and a relative increase in the weight of the spleen and liver in females and of the testes in males. This suggests that propanil is absorbed into the bloodstream through the gastrointestinal tract and, that once in the bloodstream, propanil is metabolized by the body. The liver breaks down propanil to aniline derivatives.
Excretion is through the urine.
All contamination of streams and lakes with propanil should be avoided. Propanil appears to have very low toxicity to mammals. Only information on lab animals such as rabbits, rats and dogs was found. Fungi use it as a carbon source. Bacteria produce highly colored by-products such as tetrachloroazobenzene.