Xue told Xinhua he was astonished by the sight of a bus sandwiched between huge cracks in the street with passengers trapped inside.
"Some cars along the street are turned over, some are covered with concrete slabs, and some others have lost their window glass," he said.
Wang Aihua, a doctor at Huangdao District People's Hospital, said they have received more than 20 patients injured in the accident and are expecting more.
Some residents have evacuated from the area for fear that a second explosion might occur, added Wang.
A staff member from Huangdao District Hospital of Traditional Chinese Medicine told a Xinhua reporter by phone on Friday night that the hospital had received more than 50 patients since the blast, with some of them under emergency treatment.
The male staff member, speaking on condition of anonymity, confirmed that there had been fatalities, but he refused to reveal a number.
Most of the injuries were fractures due to the force of the blast, he said.
More then 800 doctors and nurses from the hospital have participated in the rescue efforts, he added.
The 176-km pipeline is owned by Sinopec, China's largest oil refiner, and links oil depots in Huangdao with Weifang City, home to a few petrochemical plants.
The pipeline, with a total investment of 1.3 billion yuan (211.8 million U.S. dollars), was put into operation this August. It has an annual transportation capacity of 15 million tonnes.
Huangdao District is connected with the city proper by the Qingdao Jiaozhou Bay Bridge.
Xinhua reporters said the exit on the bridge leading to Huangdao has been temporarily closed and only emergency vehicles are allowed to enter. Local traffic authorities have urged drivers to make way for rescue vehicles.
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