At certain levels, lead can be harmful to human health. According to the World Health Organization (WHO) and the US Centers for Disease Control and Prevention (CDC), lead exposure can affect nearly every system in the body, especially in children. Children with high levels of lead in their bodies can suffer from brain / nervous system damage, behavior and learning problems, hyperactivity, slowed growth, hearing problems, headaches. Adults with high lead levels can suffer from reproductive problems, high blood pressure, hypertension, nerve disorders, memory and concentration problems, muscle and joint pain.