YINCHUAN - Villagers were evacuated due to a poisonous chemical leak following a road crash Tuesday morning in North China's Ningxia Hui autonomous region, according to local authorities.

The accident occurred at 8:30 am in Yuanzhou district in the city of Guyuan when a truck rear-ended a fuel tank truck loaded with 20 tonnes of crude benzene which caused an explosion, local police said.

The gas from the incomplete combustion of the crude benzene was poisonous to humans, local police said.

The amount of casualties is not known, and the cause of the accident is under investigation.