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. Children of agricultural workers are more likely to come into contact with chlorpyrifos. A study done in an agricultural community in Washington State showed that children who lived in closer proximity to farmlands had higher levels of chlorpyrifos residues from house dust. Chlorpyrifos residues were also found on work boots and children's hands, showing that agricultural families could take home these residues from their jobs. Urban and suburban children get most of their chlorpyrifos exposure from fruits and vegetables. A study done in North Carolina on children's exposure showed that chlorpyrifos was detected in 50% of the food, dust, and air samples in both their homes and daycare, with the main route of exposure being through ingestion. Certain other populations with higher likely exposure to chlorpyrifos, such as people who apply pesticides, work on farms, or live in agricultural communities, have been measured in the US to excrete TCPy in their urine at levels that are 5 to 10 times greater than levels in the general population. As of 2016, chlorpyrifos was the most used conventional insecticide in the US and was used in over 40 states; the top five states (in total pounds applied) are California, North Dakota, Minnesota, Iowa, and Texas. It was used on over 50 crops, with the top five crops (in total pounds applied) being soybeans, corn, alfalfa, oranges, and almonds. Additionally, crops with 30% or more of the crop treated (compared to total acres grown) include apples, asparagus, walnuts, table grapes, cherries, cauliflower, broccoli, and onions. Air monitoring studies conducted by the California Air Resources Board (CARB) documented chlorpyrifos in the air of California communities. Analyses indicate that children living in areas of high chlorpyrifos use are often exposed to levels that exceed EPA dosages. A