Six people lost their lives while carrying out maintenance work inside a sewer well in Kazakhstan's Pavlodar Region.

The incident occurred on July 20 at an enterprise in the village of Zholaman in the Aktogay District. Emergency responders found the bodies of six men, 17, 20, 28, 43, 51, 63, The Caspian Post reports via Nur.kz.

A seventh worker, 38, was rescued and taken to the Aktogay District Hospital.

The survivor was hospitalized with moderate carbon dioxide poisoning. His condition is stable, and doctors said he does not require transfer to a hospital in Pavlodar.

Preliminary information indicates the tragedy occurred while workers were repairing an electric pump inside the sewer well.

Police in the Pavlodar Region have opened a criminal investigation, and are working to determine the exact circumstances of the fatal incident.