ROSTOV-ON-DON, May 21. /TASS/. Ten individuals have lost their lives due to an accident at a water treatment plant outside the city of Taganrog, in Russia’s Rostov Region, a source familiar with the situation told TASS on Friday.

"Ten people have been killed, four have been rushed to the hospital and several more remain inside the collector facility," the source said.

Taganrog administration head Andrei Lisitsky confirmed the figures to TASS. "Ten are dead," he said in response to a question about the number of victims

According to preliminary data, an emission of methane occurred, Taganrog Water Service Company Director Yevgeny Pletmentsev told TASS.

The regional branch of the Russian Investigative Committee has opened a criminal case under Article 217.2 of the Russian Criminal Code (violation of industrial safety requirements causing the death of two or more persons through negligence).