Guests at a birthday party Friday for an Instagram influencer said the sauna was too hot and wanted to jump into the swimming pool to cool off. So dry ice was dumped into the Moscow pool to make the water colder. Immediately after jumping in, the people in the water began to choke, the BBC reports. Several of them became unconscious. Three people died, including Valentin Didenko. The party was in honor of his wife's 29th birthday; Ekaterina Didenko, who posts advice on saving money on pharmaceutical products, has more than a million Instagram followers. Four other people at the party suffered chemical burns, per the Moscow Times. The victims' cause of death was suffocation, officials said in a preliminary finding.
The dry ice, which is the solid form of carbon dioxide, was to be used to create a cloud of fog over the swimming pool. In an area without adequate ventilation, people can inhale dangerous amounts of it. Placing dry ice in water also can cause an explosion. Russian authorities ordered a criminal investigation of the deaths. (Read more dry ice stories.)