Volgograd Sewage Station Explosion: Engineer Faked Safety, Prosecution Says

Absence of emergency ventilation and gas sensors. Constant accumulation of toxic and explosive gases. Exceeding the maximum allowable levels of hydrogen sulfide and methane. Nearly four years of ignoring employee complaints about the deadly dangers of work. And creating the appearance of effective work for management to achieve minimal costs for «Water Supply Concessions» in fulfilling the concession agreement with the Volgograd administration. All this, according to the investigation and state prosecution, became the cause of the explosion at the sewage pumping station in the Krasnoarmeysky district of Volgograd and the death of six people.

Here are the main points from the speech by the state prosecutor, deputy prosecutor of the Krasnoarmeysky district of Volgograd Darya Lebedeva, during the closing arguments in the criminal case against her namesake and defendant — chief engineer of «Water Supply Concessions» Dmitry Lebedev.

He Created a Facade of Effective Work

The prosecutor insisted: for nearly four years, from July 2020 to July 2024, employees subordinate to Dmitry Lebedev at LLC «Water Supply Concessions» reported dangerous working conditions at sewage pumping station KNS-4. There, a gas-air mixture accumulated with exceeding maximum allowable concentrations of hydrogen sulfide, methane, toxic and explosive gases. At the same time, the ventilation system at the station was malfunctioning, and emergency ventilation and alarms were absent.

«Despite this, Dmitry Lebedev did not ensure the proper condition of the premises and the safety of workers,» stated Darya Lebedeva. «He created a facade of effective work for management to achieve the necessary indicators for wastewater disposal with minimal costs in accordance with the requirements of the concession agreement to receive salary, bonuses, and maintain his social status. At the same time, he reliably knew about the need to stop the operation of KNS for the reconstruction of the ventilation system due to exceeding the allowable concentration of toxic gases, violation of regulatory requirements.»

Death of Workshop Foreman Kurakin

69-year-old workshop foreman Mikhail Kurakin died at KNS-4 a day before the explosion. On his last working day before vacation. His relatives are convinced: the man was fatally poisoned due to horrific gas levels at the sewage pumping station. The prosecutor«s representative stated in court: Lebedev»s inaction and his violation of labor safety requirements led to the death of Mikhail Kurakin.

«On the morning of 5 July 2024, workshop foreman Kurakin arrived at his workplace. Subordinates reported the accumulation of toxic gases in the receiving chamber of KNS and refused to perform their duties due to an immediate threat to life and health,» stated Darya Lebedeva. «In connection with this, Kurakin descended into the station»s receiving chamber, where there was no system to monitor the content of toxic and explosive gas. The operation of KNS under such conditions arose from Dmitry Lebedev«s inaction.

While inspecting the technical condition of the receiving chamber and the equipment there, Mikhail Kurakin received a signal about gas contamination in the room. He headed to the staircase leading from the receiving chamber outside, but lost consciousness. Rescuers called to the scene evacuated the body from the receiving chamber, and medics recorded death from acute poisoning by a gas-air mixture, in which the leading poison was hydrogen sulfide.

He Sought to Hide His Criminal Recklessness

On 5 July 2024, Dmitry Lebedev ordered the installation of an exhaust fan on the technological opening of the receiving chamber from outside the building.

According to the investigation, he did this «to hide his criminal recklessness, which led to Kurakin»s death,« and he gave orders to subordinates who did not have the corresponding job duties or permits for construction work. Moreover, they had to act in a place where the content of toxic and explosive gases was exceeded. Especially since the head of the KNS workshop had reported to Lebedev about severe gas contamination at KNS, insisting on the urgent need for ventilation reconstruction and repair of the gas analyzer system.

Two-Stage Volumetric Explosion

Witnesses from among the employees of LLC «Water Supply Concessions» confirmed in court that from May to June 2024 in the receiving chamber, exceeding the MAC of dangerous gases was constantly recorded, mainly hydrogen sulfide. Moreover, the exceedances were recorded with a portable analyzer, not a stationary one, as the latter had not passed verification.

There was also no emergency alarm in the KNS building to report exceeding MAC. Furthermore, KNS-4 was not equipped with emergency ventilation. When exceeding MAC became constant, from the end of June 2024, operators did not descend into the receiving chamber at all.

But by order of Dmitry Lebedev, on 6 July, a repair crew was supposed to remove the exhaust fan and place it in the technological opening. At 09:30, the crew began work on installing the fan.

The investigation states that on 6 July 2024 at 13:29, during the work, a two-stage volumetric explosion of a gas-air mixture of combustible sewage gases occurred. Five people who were at KNS-4 at that moment died: shift supervisor Yuri Zuev, welder Vladimir Kuznetsov, fitter Oleg Korolchenko, electrician-fitter Mikhail Khokhlov and fitter Alexander Shestopalov. There should have been one more person — fitter Zavyalov, but he fell ill because the day before he had gone down, trying to help Kurakin.

«Non-compliance with the requirements of regulatory and technical documents is causally linked to the occurrence of the explosion at KNS and the death of employees,» read Darya Lebedeva. «Moreover, as a result of the explosion, the KNS building is destroyed without possibility of operation.

Technical forensic examination established that the technical cause of the explosion was the formation of an explosive air mixture of combustible sewage gases in the room of the KNS receiving chamber. The main combustible components of the mixture were methane and hydrogen sulfide with a predominant content of methane. The source of the gases was sewage wastewater and fecal masses undergoing filtration in the lower underground room. The most probable source of ignition of the gas-air mixture was a stream of sparks from an angle grinder during metal cutting.

Technical and Organizational Causes of Deaths at KNS-4

Prosecutor Lebedeva referred to the conducted forensic construction and technical examination.

The technical causes of Mikhail Kurakin«s death were the inoperative state of the supply and exhaust ventilation of KNS-4, lacking supply and exhaust air ducts, and the absence of a stationary gas analyzer with sensors installed in the KNS receiving chamber. The organizational cause of Mikhail Kurakin»s death was the violation committed by Dmitry Lebedev, expressed in the unsatisfactory technical condition of KNS-4.

The technical cause of death in the explosion of Yuri Zuev, Vladimir Kuznetsov, Oleg Korolchenko, Mikhail Khokhlov, and Alexander Shestopalov was the formation of an explosive gas-air mixture of combustible gases, methane and hydrogen sulfide with a predominant content of methane in the room of the KNS-4 receiving chamber. The organizational cause of death of the five men was the violation committed by Dmitry Lebedev, expressed in the unsatisfactory technical condition of KNS-4.

No Link Between Petroleum Products and Explosion

Recall that it was previously repeatedly stated that petroleum products were found in the wastewater at KNS-4. People reported the smell of oil coming from the KNS-4 drains long before the explosion. Dmitry Lebedev also insists on the connection between the station«s problems, the explosion, and the deaths with discharges of petroleum products into the sewer network. But the prosecutor»s office of Volgograd Oblast completely dismisses this version. And in her speech, the prosecutor only mentions these discharges in passing.

«By the conclusion of the judicial examination, in samples of wastewater seized on 5 July 2024, water was discovered, the presence of mercaptan, traces of hydrogen sulfide and hexane, as well as mechanical impurities in the form of a black amorphous mass,» thus Darya Lebedeva mentions this fuel-oil-like mass that filled the lower parts of the station. «In the gas phase of the liquid, carbon disulfide and hydrogen sulfide were found as main components, as well as trace amounts of hexane.

Thus, contrary to the accused«s version, no link has been established between the presence of petroleum products in the sewer network and the death of employees. According to witnesses and instrument readings, a significant exceedance of allowable levels of hydrogen sulfide and methane has been recorded at the station for a long time.»

According to Darya Lebedeva, the medical examination concluded that for the death of Mikhail Kurakin, the concentration of hydrogen sulfide alone that had formed was sufficient. And the predominant gas in the mixture that exploded on 6 July was methane. Both gases are formed in sewage water as a result of natural biological processes.

«The formation of an explosive gas-air mixture in the volumes of the receiving chamber rooms was a consequence of the improper operation of the KNS system, including due to the absence of local pumps in the room and grates in the receiving chamber,» stated Darya Lebedeva. «Moreover, KNS-4 lacked a system of constant monitoring of the content of such gases with the help of analyzer instruments, warning alarms, and emergency ventilation.»

The prosecutor insisted: Lebedev«s obligation to ensure the safe condition of the pumping station building is directly provided for by his job description.

«Only he could give the order to stop the operation of KNS-4, which was not done,» stated Darya Lebedeva. «As chief engineer, Lebedev was responsible for developing and implementing measures for the reconstruction of the KNS ventilation system, determined their cost, included in the program for compensating expenses through charging utility tariffs from the population of Volgograd. Instead, as a result of his criminal recklessness, since 2020 he allowed the station to operate under conditions of real danger to the life and health of employees of »Water Supply Concessions«. I believe the evidence is sufficient for a guilty verdict.»