A News.com.Au news report indicates that experts may have uncovered the cause of a mysterious sleeping illness impacting a small village in Kazakhstan.

“On the basis of results from the working group, a preliminary conclusion has been made on the possible connection between the symptoms and high concentrations of vapors that have built up during the heating season in basements and poorly ventilated living spaces. Tests conducted in the homes of patients are evidence of this,” the ministry said in a statement, according to Diapazon.kz.