The Peking man site at Zhoukoudian is facing an unprecedented threat from humans and natural disasters.

Experts warned that it might be taken off the World Heritage Site list if no action was taken to protect it.

Among the 27 locations that are regarded as of high archeological value, 21 are in danger of collapse. A conference on the protection of Zhoukoudian told Tuesday.

When Pei Wenzhong astonished the world with his finding of the Peking man skull at Shandingdong on Dec. 2, 1929, the cave was complete. Now half of the cave was exposed to the elements, said Mou Huichong, a professor with the Chinese Academy of Sciences (CAS).

Four experts from the CAS began surveying the geological conditions around the site Oct. 9. It was the first survey of the site since it was included in the World Heritage Site list in 1987.

Several caves with Peking man relics are located on unstable hills. A major rain storm could cause landslides, destroying an important heritage as well as discouraging tourists, said Mou.

Experts with the CAS said earthquakes, explosions and trains could have contributed to the dangerous geological conditions.

There were also stone quarries and cement factories near the site. Explosions from the stone quarries rocked the hills and acid rain caused by the cement factories eroded the rocks.

There is a railway line not far from the site and as trains pass, they cause vibrations in the hills.

Improper archeological excavation and weathering were also reasons for the deterioration of the site.

Liu Guangyu, head of the Zhoukoudian Protection Committee, said the committee had always been short of funds. If no action was taken, the site might be dropped from the World Heritage Site list.

An official with the Zhoukoudian management office said the survey report would be studied by experts later this month. If everything went smoothly, repair work would begin in March 2004, he said.

The management office is now clearing the factories away from the site and moving residents out of the area.

The whole protection project would need up to 100 million yuan (US$12.5m), said the official.

Located some 42 km southwest of Beijing, Zhoukoudian is where the first skull fragments of Peking man were found, dating back 500,000 years. It preserves evidence of the earliest human use of fire and is the only site continuously inhabited by prehistoric man between 500,000 and 10,000 years ago.

(Shenzhen Daily December 5, 2003)