Oil based paints contain solvents to disperse and bind other paint components. Solvents are the major ingredients that contribute to volatile organic compound (VOC) levels in paints. VOCs can cause the formation of ozone and photochemical smog, which have harmful effects on human health and the environment. Paints that are specifically marketed as "fast drying" usually contain even higher levels of these solvents. Buying low VOC paints will reduce exposure to harmful chemicals and will reduce hazardous waste disposal costs for properly dispose of any leftover paints.