Russian doomsday sect members who have been barricaded in a cave in the country's central Penza Region since the fall could die from infection and poisonous fumes, the Tvoi Den tabloid paper said.
The group of about 35 cult members, including four children, are holed up in the cave waiting for the apocalypse, which they say will happen in May 2008. They have threatened to set fire to themselves if any attempt is made to force them out.
"The situation in the Penza cave is very serious. Three dozen people have been in a small enclosed space for a long time. Even if they have a toilet with a septic tank it will not save them from poisonous ammonia gases," an extreme tourism instructor, Nadezhda Moiseyeva, said.
The cult members are being choked by the stench of their own excrement, she added, and with the onset of warmer weather they could simply suffocate or their water could become infected by bacteria, as their well is located next to the toilet.
"Poisonous fumes are the greatest threat to the children living in the cave... I'm frightened to think about their fate!" she said. The youngest child is thought to be less than eighteen months old.
She added: "Any cave is a source of radiation." Radon, a naturally occurring gas, causes headaches, decreased immunity and hair loss, the extreme tourism specialist explained.
According to the sect's founder, Pyotr Kuznetsov, the cave is said to have been divided into five cells, with one large 'room' set aside for prayers. The prayer room is also to be used for the eventual burial of the sect members.
Kuznetsov, who calls himself a saint, is currently being treated for paranoid schizophrenia in a psychiatric hospital in Penza, about 600 km (370 miles) southeast of Moscow.
Moiseyeva also warned that the cave was located near an abattoir, where cattle and dead animals are buried. "The situation could be called catastrophic, as a virus will have certainly reached their drinking water. They are poisoning themselves without knowing it!"
The government of the Penza Region is currently considering the possibility of setting up a rescue station near the cave in case of spring flooding. "We are ready to provide aid to the cult members hiding underground...We will do everything we can to help these people in case of a threat," a government spokesman said.
There are currently believed to be around 500-700 such sects in Russia with some 600,000-800,000 members.