Malathion is a widely used insecticide that is known to contain various impurities. These impurities can arise during the manufacturing process or from the degradation of malathion over time. Some of the common impurities found in malathion include malaoxon, isomalathion, and dimethyl dithiophosphate. These impurities can have toxic effects on the environment and human health, making it important to monitor and regulate malathion production and use.