All sections of the population are at risk of exposure, however, most cases of lead poisoning go undetected because at lower but still harmful levels only a small per centage who suffer from lead poisoning display obvious symptoms. Except at very high levels, lead poisoning is difficult to diagnose without a blood lead test.

Children under the age of six years are most susceptible to the harmful effects of lead because their neurological systems are still developing. At even low levels lead poisoning in children causes reduction of Intelligence Quotient points, shortened attention span, hyperactivity, aggressive behaviour, reading disabilities, and other learning and behavioural problems. These effects may be irreversible. Other effects include reduced growth, hearing loss, and low birth weight. Very high lead exposures can cause mental retardation, coma, convulsions, and death. Adverse effects in adults include high blood pressure; nerve, liver and kidney damage; and impaired fertility. Increased lead content in blood is of particular concern for pregnant women and women of childbearing age. In addition, lead absorbed during childhood and stored in the bones can be released back into the blood during pregnancy, harming the developing foetus as well as the mother.