Occupational Hazards and Protection of Carbon Tetrachloride

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Original Title: Occupational Hazards and Protection of Carbon Tetrachloride Carbon tetrachloride (CCL) Also known as tetrachloromethane, it is a colorless, transparent, volatile and non-flammable oily liquid at normal temperature and pressure, with a slightly sweet odor similar to chloroform. Its molecular weight is 153.84 and boiling point is 76.8 C | C. It is slightly soluble in water and miscible with ethanol, ether, chloroform and petroleum ether. Carbon tetrachloride has been widely used as solvent, fire extinguishing agent, chlorinating agent of organic matter, leaching agent of spice, degreasing agent of fiber, cooking agent of grain, extracting agent of medicine, organic solvent, dry cleaning agent of fabric, lubricant in metal cutting, etc. It can also be used to synthesize the monomer of Freon and nylon, and can also be used to make chloroform and medicine. At present, it is clear that it has strong hepatotoxicity. Carbon tetrachloride poisoning is a legal occupational disease in China, which is mostly caused by inhaling its high concentration vapor in productive labor, and is characterized by central anesthesia symptoms and liver and kidney damage. Toxicity characteristics and hazards Carbon tetrachloride can be decomposed into carbon dioxide, hydrogen chloride, phosgene and chlorine when exposed to fire or hot substances. Carbon tetrachloride and its decomposition products can be absorbed into the body through respiratory tract and skin contact, and metabolize rapidly in the body. After inhalation, about 50% of them are discharged from the lungs in their original form, 20% of them are oxidized and transformed in the body, and the final product is carbon dioxide. Carbon tetrachloride vapor has a mild stimulating effect on the mucosa, an anesthetic effect on the central nervous system, and serious damage to the liver and kidney. Acute carbon tetrachloride poisoning: Inhalation of high concentrations of carbon tetrachloride vapor in a short period of time can quickly lead to coma, convulsions and other central nervous system symptoms, as well as pulmonary edema and respiratory paralysis. Inhalation of a slightly higher concentration can cause dizziness, headache, fatigue,Virus Prevention Mask 3 Ply with Earloop, staggering gait or mild disturbance of consciousness. Signs of liver and kidney damage were observed on the 2nd to 4th day of poisoning. In severe cases, ascites, acute liver necrosis, and renal failure occur. The main manifestations of chronic poisoning are neurasthenic syndrome and gastrointestinal dysfunction, and a few may have hepatomegaly and abnormal liver function. Poisoning causes and preventive measures Inhalation of high concentration carbon tetrachloride vapor is mainly seen in the chemical industry manufacturing dichlorodifluoromethane, trichlorofluoromethane and chloroform, etc. Due to the lack of good ventilation in the workshop and accidental leakage of equipment pipelines, a large amount of high concentration carbon tetrachloride vapor is inhaled in a short time. It can also occur when carbon tetrachloride extinguishers are used to extinguish fires in stuffy rooms, or when carbon tetrachloride is used to fumigate, dry clean, and scrub guns or machines. It is rare to take carbon tetrachloride liquid by mistake and absorb it through digestive tract or contaminated skin. When carbon tetrachloride contacts flame or hot metal,3 Ply Disposable Protective Face Mask, it is easy to decompose a large amount of phosgene and hydrogen chloride, and phosgene hazards can occur at this time. Precautions The production process shall be kept closed as far as possible, and the equipment shall be overhauled regularly to prevent leakage, leakage, dripping and leakage, and to prevent steam leakage into the air of the workplace. The production site shall be provided with good ventilation facilities. Operators must be specially trained and strictly abide by the operating procedures. It is recommended that operators wear direct gas mask (half mask), safety goggles, anti-poison penetration work clothes and anti-chemical gloves. Handle with care to prevent damage to packages and containers. Store in a cool and ventilated warehouse. Keep away from kindling and heat sources. The temperature of the storehouse shall not exceed 30 ℃ and the relative humidity shall not exceed 80%. Keep the container sealed and store it separately from oxidants, active metal powders and edible chemicals. Do not mix them. The storage area shall be equipped with spill emergency treatment equipment and suitable containment materials. Smoking, eating and drinking are prohibited on the work site. After work, wash the hands, face and other parts that may be contacted thoroughly. Store clothes contaminated by poisons separately and wash them for later use. Carry out pre-employment and regular physical examination, and those who suffer from neuropsychiatric system and liver and kidney organic diseases are not allowed to work. Strengthen the special storage of this product, and the label should be clear and eye-catching to prevent misuse and misuse. Emergency rescue and disposal principle Expand the full text First aid measures Quickly remove the poisoned person from the scene to a place with fresh air. Keep the airway open. Uch as dyspnea, oxygen. If breathing stops, give artificial respiration immediately. Seek medical treatment in time. In case of skin contact, immediately remove contaminated clothing and rinse skin thoroughly with soap and water. In case of eye contact, lift the eyelids and rinse with flowing water or normal saline. When ingested by mistake, drink enough warm water to induce vomiting. Gastric lavage.
Seek medical treatment in time. Fire protection measures Carbon tetrachloride will not burn, but in case of open fire or high temperature, it is easy to produce phosgene and hydrogen chloride smoke with strong irritation and corrosiveness. Firefighters must wear filter gas masks (full face masks) or isolation respirators, wear full-body fire-proof and gas-proof suits, and put out the fire in the windward direction. Extinguishing agent: atomized water, Medical Quickly Delivery Antivirus Coverall ,Medical Full Body Coverall, carbon dioxide, sand. Emergency treatment of leakage Emergency treatment: quickly evacuate the personnel in the leakage contaminated area to the safety area, isolate them, and strictly restrict access. Emergency response personnel are recommended to wear self-contained positive pressure respirators and protective clothing. Do not make direct contact with the leak. Cut off the leakage source as far as possible. Small amount of leakage: absorb with activated carbon or other inert materials. Large amount of leakage: build a dike or dig a pit for shelter. Spray water to cool and dilute the steam to protect the personnel in the open field, but do not spray water directly to the leakage point. Transfer to tank car or special collector by pump, recycle or transport to waste treatment site for disposal. Cases of poisoning Case 1 From December 25, 2004 to January 5, 2005, 39 workers in the inspection workshop of a weaving factory had different degrees of dizziness, nausea, vomiting, fatigue, loss of appetite and other symptoms, and were sent to the local health center for treatment. The on-site occupational hygiene investigation found that the factory used organic solvent "gun water" in the decontamination process of the inspection workshop, more than 30 employees were directly exposed to it, only ceiling fans were installed in the workshop, there were no ventilation and detoxification facilities, and the operators did not use effective personal protective equipment. The windows are closed due to the cold weather, and the working hours are 10 to 12 hours a day. The packaging container of "Gun Water" is marked as "1,1,1 trichloroethane, with a content of more than 96%." The daily consumption of the accident workshop is more than 10 liters. The sample of "gun water" was taken on the spot for composition analysis, and the results showed that it contained 57.4% carbon tetrachloride and 42% dichloromethane. The results showed that the concentration of carbon tetrachloride in the air of 10 detection points exceeded the national occupational health standard, and the highest concentration was 192 mg/m3, which exceeded the standard by 6. 6 times. According to the clinical manifestations, laboratory examination results and occupational health survey results of the workers, and according to GB242-2002 Diagnostic Criteria for Occupational Acute Carbon Tetrachloride Poisoning, 18 of the 39 workers were diagnosed as occupational mild acute carbon tetrachloride poisoning. Analysis of the causes of poisoning: At present, the market of cleaning agents is not standardized, the management is disorderly, the varieties are complicated, there are many "three noes" products, and the content of highly toxic chemicals is high. What's more, some people use foreign languages or codes to conceal the true names of chemicals, and there are no instructions and Chinese labels for toxicity. The main components of the so-called "gun water" in this accident are 57.4% carbon tetrachloride and 42% dichloromethane, while the factory container is labeled "1. The content of 1,1-trichloroethane is more than 96%, which misleads users and buries hidden dangers of accidents. In addition, poor equipment, imperfect detoxification facilities and lack of effective protective measures are the main causes of poisoning accidents. It is suggested that the factory should improve the production environment, separate the toxic and non-toxic processes in the production workshop, and reduce the hazardous area of poisons. Improve ventilation and detoxification measures, strengthen personal protection, and reduce the occurrence of occupational poisoning incidents. At the same time, efforts should be made to strengthen occupational safety and health education for workers and enhance their awareness of self-protection. Case II Patient 1: Male, 30 years old, ship engine worker, one day in the engine room of a small cargo ship, the ship engine was cleaned by spraying and scrubbing. The volume of the engine room was about 40 ITl3, and the ventilation in the cabin was poor. After half an hour, he felt dizzy, weak and uncomfortable. He went to the deck to ventilate and rest for about 10 minutes. After the symptoms improved, he returned to the cabin to continue working. About 2 H in total, more than 10 kg of carbon tetrachloride was used. Immediately, the patient found that the urine was brown and there was no blood clot. Nausea and vomiting occurred the next day, and self-perceived urination gradually decreased. On the evening of the third day, when the ship arrived at the dock, there was no urine in one day, and he was diagnosed with carbon tetrachloride poisoning, renal failure and uremia after visiting the hospital. Patient 2, male, 54 years old, was operated at the same time as patient 1, but the time was longer, about 4 hours in total, and the symptoms were similar to patient 1. He was also hospitalized and diagnosed with carbon tetrachloride poisoning, renal failure and uremia. The above two patients were discharged after hemodialysis and symptomatic treatment.
Poisoning cause analysis: Workers did not understand the toxicity and hazards of carbon tetrachloride, did not pay attention to personal protection at work, worked for a long time without detoxification facilities, and absorbed a large amount of carbon tetrachloride through respiratory tract and skin,KN95 Mask for Epidemic Prevention and Control, resulting in poisoning. The above is the whole content of the article. If you have any questions and needs, you can consult us immediately, or visit: China Occupational Disease Network for exchange and discussion. Return to Sohu to see more Responsible Editor:. zjyuan-group.com