Another outbreak of severe lead poisoning has been reported in China, this time in the central Henan Province.

According to Chinese state media, nearly 1,000 children in Jiyuan city have been found to have excessive levels of lead in their blood.

Since last month, local villagers have been protesting outside factories belonging to the Yuguang Gold and Lead Group. They say the lead smelting plants, which have been operating since 1954, are responsible for the lead poisoning.

Chinese state-run media reports that Jiyuan city authorities have promised to relocate families within 0.6 miles of the factories. They say children under 14 in the area will receive free tests for lead poisoning.

This latest outbreak follows a string of similar lead poisoning incidents in Yunnan, Fujian and Shaanxi provinces in recent months. These cases highlight the environmental and human costs of China’s rapid development and poor regulation.