Humans can be exposed to chlorpyrifos by way of ingestion (e.g., residue on treated produce, drinking water), inhalation (especially of indoor air), or absorption (i.e., through the skin). However, compared to other organophosphates, chlorpyrifos degrades relatively quickly once released into the environment. According to the National Institutes of Health, the half-life for chlorpyrifos (i.e., the period of time that it takes for the active amount of the chemical to decrease by 50%) "can typically range from 33–56 days for soil incorporated applications and 7–15 days for surface applications"; in water, the half-life is about 25 days, and in the air, the half-life can range from four to ten days.