Update | Anger in wake of deadly Qingdao explosion

A day after an explosion triggered by a leaking underground oil pipeline killed at least 52 people and injured more than one hundred in Qingdao, Shandong province, residents were seeking explanations for one of China's deadliest industrial accidents in years.

Xinhua reported yesterday that some 18,000 people had been evacuated and the government had provided food and candles to survivors. But some residents criticised authorities for not issuing warnings or evacuating people living nearby after failures in the pipeline appeared seven hours before the blast ripped up roads and shattered windows.

At least 11 people remained missing as of Sunday afternoon, the local government in Huangdao district said. 

The pipeline leaked onto the street and into the harbour nearby for about 15 minutes before it was shut down at about 3.15am on Friday.

The explosion occurred seven hours later as workers were trying to repair the leak in the pipe, Xinhua said. It also said early investigations found that oil that spilled into drains caused the explosion, but gave no further details.

The reports only deepened residents' unease in the historic port city of nearly 9 million people. Shandong is home to one of the largest crude-oil import terminals in the country, and controls one-seventh of the nation's oil and gas pipelines.