An investigation into the Tunlan Coal Mine accident has announced that poor ventilation, bad management and insufficient safety measures were three of the key factors to blame. The team, led by the head of the State Administration of Work Safety, was reporting to the State Council.

Governor of Shanxi Province Wang Jun (R) wipes tear as he makes an apology to victims and their families over the gas blast at the Tunlan coal mine that left 74 people dead and 114 others injured, in Taiyuan, north China's Shanxi Province on Feb. 24, 2009. [Jin Liangkuai/Xinhua]

Based on preliminary investigations, the causes of Sunday's accident are safety loopholes in the ventilation, site management, gas extraction and safety measures.