Carbon disulfide poisoning cannot be ignored

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At around 7 a.m. on May 16, 2015, a leak occurred in the carbon disulfide production unit at Ruixing Chemical Co., Ltd. in Yangcheng County, Jincheng City, Shanxi Province; an poisoning accident took place during maintenance work, resulting in 8 deaths and 6 injuries. The accident occurred in the carbon disulfide cooling tank, which is a rectangular tank measuring 8.4 meters in length, 4.4 meters in width, and 2.2 meters in depth. During normal production, the products of the synthesis reaction (carbon disulfide and hydrogen sulfide gases) pass through the cooling tubes inside the tank; carbon disulfide is condensed into a crude product, while the exhaust gas containing hydrogen sulfide is recycled. 　　According to preliminary analysis, the direct cause of the accident was a leak in the cooling pipes inside the carbon disulfide cooling tank. One operator entered the tank to repair the leak without detecting any toxic gases, without obtaining the necessary permits for working in confined spaces, and without using any appropriate protective measures, which led to his poisoning. The other 13 people attempted to carry out rescue efforts blindly, which resulted in an increase in the number of casualties. Physical and chemical properties of carbon disulfide: Carbon disulfide is a colorless or pale yellow transparent liquid with an irritating odor. It is volatile, insoluble in water, but soluble in most organic solvents such as ether and ethanol. Its vapor forms an explosive mixture with air, and it can easily catch fire and explode in the presence of an open flame or high heat. It can react violently with oxidizers. Its vapor is heavier than air, allowing it to spread over considerable distances at lower levels, and it can reignite when exposed to a source of fire. High-speed impact, flow, and turbulence can lead to combustion and explosion due to the generation of static electric spark discharges. Occupational exposure: Carbon disulfide is a widely used chemical solvent in industry; it is also employed in the production of viscose fiber, rubber vulcanization, tetrachloroethylene, pesticides, and for grain fumigation. The time-weighted average permissible concentration in workplace air shall not exceed 5 mg/m3, and the short-term exposure permissible concentration shall not exceed 10 mg/m3. Harm to the human body: The main ways in which carbon disulfide causes damage to the human body are through inhalation and skin absorption. It is a toxin that damages nerves and blood vessels; it has a paralyzing effect on the central nervous system and causes damage to the peripheral nervous system. Prolonged exposure to low concentrations of this substance can lead to vascular disorders. In mild cases of acute poisoning, symptoms include headache, dizziness, effects similar to those of alcohol intoxication, unsteady gait, and impaired consciousness ； In severe cases, there is first a state of intense excitement, followed by delirium, loss of consciousness, coma, etc.; death can occur due to paralysis of the respiratory center ； Severe poisoning can leave behind a neurasthenia syndrome, sometimes accompanied by neurological disorders and peripheral nerve damage. Chronic poisoning: It is mainly characterized by neurasthenia, numbness and weakness in the distal limbs, pain in the calf muscles, and difficulty walking. It can cause sexual dysfunction; male workers often experience reduced sperm count, while female workers may suffer from menstrual disorders and miscarriages. First aid measures: In the event of a carbon disulfide leak, it is necessary to immediately evacuate people from the contaminated area to a safe zone, prevent unauthorized persons from entering that area, and eliminate any sources of fire. Emergency responders should not come into direct contact with the spill; they must seal it up while wearing gas masks or self-contained breathing apparatus to ensure their safety. Spraying mist reduces evaporation, but it does not decrease the flammability of the leak in confined spaces. Absorb with sand, vermiculite, or other inert materials, and then collect and transport to a waste disposal site for disposal. In the event of a large-scale leak, it should be contained using dikes, and then collected, transferred, recycled, or disposed of after being rendered harmless. Precautionary measures: 1. Carbon disulfide is volatile, flammable, and explosive; therefore, in the workshops where this product is manufactured and used, ventilation, lighting, and power supply systems must be equipped with fire and explosion prevention devices. Smoking or using open flames for heating is prohibited in the workshop; effective ventilation and exhaust systems must be installed. 　　2. Water should be added to the containers used for transporting or storing carbon disulfide in order to cover the liquid surface and prevent the liquid and vapors of this substance from escaping. 　　3. In viscose fiber production plants, where carbon disulfide and hydrogen sulfide coexist, equipment, containers, pipes, etc., should preferably be made of cement, ceramic, or plastic. For waste gas and waste liquid, a carbon disulfide cooling tower should be installed for recovery and treatment. 　　4. Strengthen personal protection. When working in areas with high concentrations of hazardous substances, such as cleaning viscose mixers, adding materials, clearing pipes, or feeding materials into the top of a reactor, it is necessary to wear a gas mask, plastic gloves, and protective clothing in advance to prevent skin contact. 　　5. Workers exposed to carbon disulfide should undergo pre-employment and annual occupational health examinations. Those suffering from organic mental and nervous system diseases, severe neuroses, retinal diseases, as well as liver and kidney diseases, or those suspected of having chronic poisoning, shall not be allowed to work.