The investigation of a crude oil pipeline blast in Qingdao, Shandong province, has been completed, said Huang Yi, spokesperson with the State Administration of Work Safety, on Thursday.

"The findings will soon be published," Huang told a press conference in Beijing on Thursday morning.

The fatal blast occurred at 10:30 am on Nov 22 in Qingdao's Huangdao district after crude oil leaked from a pipeline into the city's pipe network.

A total of 48 people were killed and 136 others injured.

Workers were repairing the pipeline when the blast occurred. A subsequent fire was put out at 1 pm.

About 18,000 people were evacuated from surrounding communities.