More than 60% of Gauteng children have unacceptable blood-lead levels in their systems, exceeding the US levels at which health workers would be legally required to take action. Lowered intelligence, reduced birth weight, hyperactivity and blood problems are consequences of excessive exposure to lead during early childhood. This shock finding was released by Greater Johannesburg's eastern council environment department, which found that studies among Greater Johannesburg schoolchildren indicate that blood-lead levels range from 6 to 26 micrograms per decilitre, with the average at 13. The acceptable level in the US is 10.