A fertilizer plant in southwest China discharged a "huge amount" of sulfur dioxide, sickening about 140 children and teachers, state media reported Tuesday.

The plant, which produces chemical fertilizers in the county of Xifeng in Guizhou province, emitted the colorless gas into the atmosphere Monday, the Xinhua News Agency said, citing a local official.

Five teachers and 135 students from two primary schools and a middle school reported problems breathing and were taken to a local hospital, Xinhua quoted the county's executive deputy head, Huang Yonghui, as saying.