Dr. Nguyen Trung Nguyen - Director of the Poison Control Center, Bach Mai Hospital - said that the Poison Control Center, Bach Mai Hospital facility in Ninh Binh received 8 patients in the hydrogen sulfide (H2S) poisoning incident at a pig farm in Thanh Hoa.
The scene of the accident is a closed-form water tank, 2m deep, 2m wide, 3m long, while the mouth of the tank is only more than 1m wide. The cramped space, lack of air circulation creates conditions for bacteria to break down organic matter and generate a large amount of H2S gas.
Initially, a male worker unfortunately fell into the tank and fainted. Seeing a colleague in trouble, many people immediately rushed down or bent deep into the mouth of the tank to pull the victim up without any protective equipment. This rescue reflex caused a chain accident to occur when the rescuers also quickly became poisoned.
According to Dr. Nguyen Trung Nguyen, hydrogen sulfide gas (H2S) is one of the most dangerous toxic gases, with a toxic mechanism similar to cyanide when inhibiting cell respiration very quickly and very strongly, causing organs, especially the brain and heart, to severely lack oxygen.
At low concentrations, H2S has a characteristic rotten egg smell. However, when the concentration increases, this gas immediately paralyzes the olfactory nerve, causing the inhaler to no longer be able to smell the smell and easily be subjective and step into the dangerous area.
In medical literature, the phenomenon of high concentrations of H2S poisoning in closed spaces is called "butcher syndrome". People entering the area with toxic gas can faint almost immediately, the heart and central nervous system are quickly affected, and the mortality rate at the scene is very high if not properly rescued.
In addition to causing rapid loss of consciousness, H2S is also absorbed very quickly through the respiratory tract and causes strong irritation of the eye mucosa and respiratory tract.
Dr. Nguyen Trung Nguyen also noted that many people still mistakenly believe that suffocations in biogas digesters, dug wells or tanks are caused by methane gas (CH4). In fact, methane gas mainly causes oxygen deficiency, while H2S is the cause that causes victims to die in a very short time.
This type of gas often appears in waste tanks, manure tanks, sewers, deep wells, biogas pits, fish holds on ships and many other closed spaces. Similar accidents still occur every year, mainly due to people and workers lacking knowledge about the danger of toxic gases and rushing to rescue people reflexively.
Recommendations to prevent H2S gas poisoning
If an unconscious person is detected immediately after entering a tank, cellar, well, sewer or closed space, it is necessary to immediately consider the risk of H2S gas poisoning. Suggested signs include red eyes, conjunctival irritation, and items made of copper, silver, and iron on the victim's body becoming dull and turning black.
Most importantly, do not rush down to rescue people as a reflex when there is no gas mask or oxygen tank. Before approaching the scene, it is necessary to ventilate, use a fan or pump clean air to push toxic gas out.
If forced to go down to a dangerous area, rescuers must have specialized protective equipment or be fastened with seat belts and always have someone on top ready to rescue.
To prevent this, absolutely do not voluntarily go down to tanks, deep wells, sewers or closed spaces without safety checks. Before working, ventilation is needed, air concentrations are measured, and respiratory protection equipment is used correctly. Just a moment of subjectivity can make many people become victims.
