According to the Centers for Disease Control and Prevention, about 1.2 million children in the United States were diagnosed as lead poisoned in 2017.
You can't see, taste, or smell lead. Lead may be in the dust, paint, or soil around your home. Lead may be in your drinking water or food. Lead does not evaporate or biodegrade. Lead will exist in the environment until it is physically removed.
Lead is a useful element and was commonly used in paint, gasoline, and plumbing until the late 1970s in the United States. Homes built before 1980 may still contain high levels of lead due to peeling paint, contaminated soils, and/or old and outdated plumbing.
Oddly enough, lead tastes sweet. Children have been known to purposely peel paint off walls or chew on window sills to satisfy their sweet tooth. Toddlers are at highest risk of poisoning because they spend so much time touching and putting objects in their mouths.