Five workers were killed and nine others injured in a carbon dioxide outburst accident at a coal mine in Lanzhou, northwest China.The accident took place while the workers were on an excavation platform in the coal mine, and the injured are currently receiving emergency medical treatment, China's Xinhua News Agency reported Monday.China's coal mining industry is considered one of the most dangerous in the world, with hundreds of accidents resulting in deaths and injuries each year, despite government efforts to improve safety standards.
