All in all, 70 children were poisoned by gas in Volgograd, after a local refinery spewed out gas for 15 consecutive minutes April 18.
39 people, including two adults and 37 children, were hospitalized April 19. Their list includes students from a local private school and those from a public school, too.
All those who requested medical aid have gas-poisoning symptoms.
Some patients are in a slightly grave condition, some in a graver one, doctors say.
According to investigators, the LUKOIL Volgogradneftepererabotka refinery's No. 2 carbon-processing unit spewed out 5-7 cubic meters of liquified propane-propylene and butane-butylene for 15 consecutive minutes April 18. Those substances contained one percent of hydrogen sulphide.
Criminal proceedings have been launched in connection with the violation of environmental safety regulations during production activity, deputy regional prosecutor Mikhail Muzrayev noted. Violators might be imprisoned for a period of up to five years and forbidden to work as managers and supervisors.
The authorities continue to investigate this gas-poisoning incident.