GUIYANG - Four people were killed and another was injured in a traffic accident that occurred in Southwest China's Guizhou province on Tuesday, according to local authorities.

The accident took place around 7 am on a highway linking the cities of Yuping and Tongren. A truck loaded with sulfur dioxide collided head-on with a motorcycle and subsequently crashed into a nearby hill, local authorities said.

Both of the people riding the motorcycle, as well as two passengers in the truck, died at the scene. The collision resulted in a sulfur dioxide spill that is still being cleaned up.

Traffic had yet to be resumed as of 10 am Tuesday. The cause of the accident is under investigation.