Exposure to lead continues to poison young children in the United States. Just a few particles of lead dust are enough to poison a child. Lead often enters the body when children put their hands or other objects covered with lead dust into their mouths. Lead exposure can cause devastating and irreversible effects because it has no biological purpose in the body. In 2012, the CDC lowered the level of lead exposure that they track to 5 mcg/dL from 10 mcg/dL. A child with even very low levels of lead exposure over time can have permanent learning and behavior disabilities.