BEIJING - Proper urban planning is needed to avoid accidents like the deadly oil pipeline blasts in an economic zone in East China's Shandong province.

As of Monday, the accident had left 55 dead, nine people missing and another 136 in hospital, after explosions ripped through residential and commercial roads in Huangdao District of Qingdao on Friday.

Yang Dongliang, director of the State Administration of Work Safety and head of an investigation team for the accident, said the unreasonable layout of oil pipelines and urban drainage pipes was identified as one of the serious problems exposed by the incident.

In a separate accident, three people were injured after a natural gas pipeline was damaged and exploded on Sunday at a construction site in downtown Wenzhou, eastern China's Zhejiang Province.

Accidents related to underground pipelines mean that better planning and effective management in urban construction is needed, according to analysts.

"It is not only a problem of design, but also related to planning and management," said Xiao Yanyang, associate professor in urban planning at Hunan University.

A special body should be set up to manage all underground pipelines in a coordinated manner, Xiao suggested.

Different pipelines are managed by different departments or companies and coordination is lacking between them. So it is difficult to deal with loopholes even if everyone is aware of them, according to Xiao.

The number of underground pipelines for drainage, electricity, communications, natural gas and heating has increased during rapid urbanization in China.

However, planning for underground pipeline networks lags behind urban development and the sharp increase of pipelines causes crowding underground, said Pan Jiahua, head of the Urban and Environmental Studies Institute at the Chinese Academy of Social Sciences.

The problem of focusing on construction while neglecting the management of the underground pipeline system needs attention, said Guo Jinsong,  researcher in urban construction at Chongqing University.

Some pipelines have been in use for 20 to 30 years and lack maintenance. Underground projects face a high number of problems, he added.

The ruptured oil pipeline in Qingdao which caused the deadly accident had been in use since 1986. At least 11 different types of pipelines have been laid in Huangdao.

Guo Jishan, a senior official of Qingdao municipal government, admitted safety risks existed because pipelines were crowded underground. Guo vowed a thorough overhaul of the network to avoid further accidents.

In many places, urban planning lacks public input and planning cannot be consistently implemented for different reasons, including the transfer of relevant officials to other places, said Ma Xuesong, associate professor in administration studies at Jilin University.

The responsibilities of planners and managers in urban planning should be clarified and the role of public monitoring should be strengthened to improve the situation, said Ma.