Police in central China's Hunan Province released 15 people who were involved in a recent protest over a lead poisoning incident that was suspected to have sickened more than 1,300 local children, police said Thursday.

"The 15 people, including 14 who turned themselves in and another one summoned by police, were released after a reprimand," said an unnamed officer in charge of Wugang Municipal Security Department.

"No compulsory measures were used in the whole process," he told Xinhua.

Local authorities shut down a smelter in Wenping town of Wugang and detained two of its executives in August after 1,354 local children were diagnosed as having excessive lead in their blood.

The plant opened in May 2008 without the approval of the local environment protection bureau.

The officer said some local residents blocked road, attacked the town government and turned over police wagons on August 8 out of rage.

He said altogether three people who were in charge of the Wugang Manganese Smelting Plant had been detained. Environmental experts had determined the factory was related to the children's lead poisoning.

Twelve of the 17 children who were sent to the capital city of Changsha for medical treatment have returned home while the other five are still hospitalized.

(Xinhua News Agency September 4, 2009)