A local government department in Qingdao, East China's Shandong province, confirmed that an overpass in the city is safe after cracks in it were found on Sunday to have been filled with foam.

"The polystyrene foam was found in the cracks of the bridge's expansion joint," said an announcement released by Qingdao's commission of urban-rural development. "According to national standards, these material should be used in expansion joints."

A netizen going by the online name of Misha8988 discovered on May 18 that someone had used foam to fill cracks in an overpass connecting Haier Road and Liaoyang East Road. The person uploaded three pictures of the structure to a micro blog, giving rise huge to concerns about its safety.

The commission conducted an inspection of the overpass and later concluded that "the polystyrene foam was exposed because external stainless steel covers were stolen, but that will not affect the bridge's safety."

Authorities said the bridge will undergo repairs as soon as possible.

Expansion joints are designed to keep bridges structurally strong, even as the materials they are made of expand and contract with variations in temperature.