Eight people died and three others were injured when a toxic chemical leaked Saturday at a plant in the southwestern Chinese city of Guiyang, authorities said, AP reported.

The leak happened as workers were unloading a shipment of methyl formate from a vehicle at a chemical handling facility.

An investigation is underway, according to the China National Emergency Broadcasting.

Methyl formate is used in a variety of chemical processes and as an insecticide. It can cause skin irritation and may be toxic if ingested or inhaled.