While blood lead levels were declining, scientific evidence was mounting to show there is no safe level of exposure to lead in infants and young children. Studies showed that adverse neurological effects were happening at lower and lower levels of lead exposure. In 2012, the Centers for Disease Control and Prevention reduced the level of lead in blood used to identify those with elevated exposure to 5 µg/dL. Today, approximately 500,000 children have levels at or above 5 µg/dL.