A MERE human breath could destroy the prehistoric treasures forever.
Yet officials have deemed it safe enough to reopen the ancient Altamira Caves in Cantabria despite the “immeasurable” risk.
The vast caves – which contain 20,000-year-old wall paintings of bison and bulls – were closed in 2002 after scientists discovered green mould on the images.
However, the “Sistine chapel of Paleolithic art” is set to open its rocky doors at the end of this year on a restricted basis.
“Altamira is an asset we cannot do without,” said Angeles Gonzalez-Sinde, Spain’s minister of culture.
However, the government’s main scientific research body, the CSIC, has voiced its fears over the unexpected announcement.
“It should not be reopened,” said director Sergio Sanchez “The risks are immeasurable.”
A scientific report recently concluded: “People who go in the cave have the bad habit of moving, breathing and perspiring.”
Declared a World Heritage Site by Unesco in 1985, the caves became so popular that hopeful visitors had to book a tour three years in advance.