MOSCOW, July 29. /TASS/. Four inmates have been hospitalized with burns following an accident involving a gas cylinder in a correctional facility in Russia’s Volgograd Region, the press service of the regional directorate of Russia’s Investigative Committee said. The office of the regional prosecutor general has launched an investigation into the case.

TASS has gathered the key facts about the incident.

- The blast occurred at Penal Colony No 9 located in Volgograd’s Traktorozavodsky District.

- Preliminarily, the explosion of a gas cylinder followed by a fire took place during work in one of the utility blocks, in a storage area for construction materials.

- An inspection into the matter is being conducted, the regional directorate of Russia’s Federal Penitentiary Service said.