LANZHOU - A family of three was killed in a gas poisoning in their illegal workshop in Northwest China's Gansu province Thursday, local authorities said.

Workshop owner Da Chaorong was found lying with his wife and son on the floor of his business in the suburbs of the city of Baiyin by Da's friend at around 11 am Thursday, said municipal officials.

The friend, surnamed Xing, called an ambulance immediately but the three were announced dead by the arriving doctors, Xing said.

Initial investigation shows that the workshop was illegal and has no proper facilities to produce chemical products, officials said.

An investigation team has been set up to look into the incident.