Vietnam’s tourism ministry has ordered Quang Binh Province to assess the geological impacts of constructing a steel ladder in Son Doong, the world’s largest cave, and suspend the project if necessary, a senior official said.
Nguyen The Hung, director of the ministry's Culture Heritage Department, said the request was issued after local media reports said concerns were mounting that the ladder could affect the cave’s geological structure.
A source from the central province said authorities were looking into the matter and would report back to the ministry.
Local media last week reported that Quang Binh's provincial government and tourism department had approved a plan to erect a ladder up a 100-meter wall (330 feet) near the end of Son Doong Cave.
British cave experts who were among the first to explore the cave have suggested that a stainless steel ladder could be useful for explorers who wish to climb the wall, which has been dubbed the Great Wall of Vietnam.
Screws and ropes would be used to assemble and hang the ladder and there would be no welding, said cave expert Howard Limbert.
The ladder could be removed at any time without causing any damage to the cave, he said.
But local media reports said cavers were concerned the project could disturb stalactites that have taken tens of thousands of years to form.
Nhan Dan newspaper, the official publication of Vietnam’s ruling Communist Party, said no environmental impact assessment for the project had been conducted thus far, adding that “caution is needed”.
Son Doong, or Mountain River, stretches more than six kilometers (four miles) underground, and boasts at least 150 individual grottoes and a dense subterranean jungle intertwined by rivers and fossilized corridors.
The cave was discovered in 1991 by local man Ho Khanh, who in 2009 helped Limbert and other British experts explore it.
It was first opened to tourists on a trial basis in August 2013, and tours are usually fully booked a year ahead.
Most tours finish at the wall, which is around six kilometers into the cave.
The exploration time for the cave could be shortened to three days from five if there’s a ladder to go past the wall.