At least 19 people have died this month in Russia’s Leningrad region after drinking what officials believe to be toxic alcohol. The deaths occurred in the Slantsy District, where authorities said several victims had consumed home made or counterfeit spirits.

Health officials confirmed that eight of the cases were caused by methanol poisoning. Methanol, a highly toxic substance, is sometimes used in the production of illicit alcohol but is deadly when ingested.

Cases of mass alcohol poisoning are not new in Russia, where unregulated and cheap substitutes are often consumed, especially in rural areas. Authorities have launched an investigation and are warning residents to avoid unlicensed alcohol products.