NANNING - Six people, including a one-year-old boy, were burned in a sulfuric acid spill in South China's Guangxi Zhuang autonomous region on Friday, local police said Saturday.

The accident happened at around 10 am Friday when the sulfuric acid was being unloaded from a truck at a plant in Xingning district of the provincial capital Nanning, said local traffic police.

Over 2 tons of sulfuric acid flew through the gate of the plant and onto a busy road outside, toppling several motorcycles and injuring at least six people, police said.

The one-year-old sustained serious burns covering 19 percent of his body, they said.

An initial investigation shows that an improper unloading practice caused the spill. Further investigation is under way, they said.