Since the early 1970s, federal agencies have conducted a public awareness campaign about lead toxicity. This campaign was spurred by the diagnosis of lead poisoning of about 2,000 children in 1970. Lead poisoning is particularly troubling in children because it interferes with their brain functions and nervous system. Why is lead so toxic? Lead mimics other metals that are important to the body including calcium, iron and zinc. The problem is that lead will not perform the same functions as the other metals and will interfere with the body's immune system. Symptoms of lead poisoning include gastrointestinal problems, lethargy, anemia and muscle pains. But since these symptoms mimic other health problems, many people do not associate these with lead toxicity. It is usually not until they notice bluish gums and a metallic taste in their mouth that they realize that they may have high levels of lead in their body.