The toxicity of chlorine and first aid measures for poisoning

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Toxicity of chlorine and first aid measures for poisoning. Product name: Chlorine; chlorine; CAS: 7782-50-5. Physical and chemical properties: Yellow-green gas with a suffocating odor. Molecular formula: Cl2. Molecular weight 70.91. Relative density 1.47 (0°C, 369.77 kPa). Melting point -101°C. Boiling point -34.5°C. Vapor density is 2.49. Vapor pressure 506.62 kPa (5 atm at 10.3°C). Soluble in water and readily soluble in alkaline solutions. When it comes into contact with water, it produces hypochlorous acid and hydrochloric acid; hypochlorous acid then decomposes into elemental chlorine, oxygen, and chloric acid in hydrochloric acid. Chlorine and carbon monoxide can produce phosgene under high-temperature conditions. This product is non-flammable, but it can assist combustion. Combination with flammable gases in sunlight can cause combustion and explosion. Reacts with many substances to cause combustion and explosion. 　　Firefighting measures: Firefighters must wear gas masks and full-body protective suits. The cylinder valve must be closed to stop the flow of gas in order to extinguish the fire; water should be used to keep the containers at the fire site cool, and water sprays should also be used to protect the personnel who are closing the valve. 　　Storage and Transportation Instructions Packaging Label: Toxic Gas. Packaging method: Cylinder-packed. Storage and transportation conditions: Store in a cool, dry, well-ventilated warehouse with non-flammable structures; it is best to use a dedicated storage area for this purpose. Keep away from heat and fire sources. Protect from direct sunlight. Liquid chlorine is a highly toxic gas, so ventilation should be maintained at all times. Keep away from flammable materials, organic substances, or other easily oxidizable substances. Special care must be taken to keep it separate from acetylene, ammonia, hydrogen, hydrocarbons, ether, turpentine, metal powders, etc. When handling, wear the safety cap for the cylinder as well as shock-absorbing rubber rings to prevent rolling and collisions, thus avoiding damage to the container. Normally, use soapy water to check for leaks in the valves and to determine whether there is chlorine in the warehouse. 　　Leak handling 　　When dealing with leaks, it is necessary to wear a gas mask and gloves. Upon detecting a leak, the valve responsible for the leak should be closed immediately. If it cannot be repaired, the leaking cylinder should be taken out of the warehouse and submerged in lime milk in an open area to prevent poisoning incidents. The residual exhaust gas is expelled using an exhaust fan to a wash tower or a fume hood connected to the tower. 　　Opportunities for contact 　Chlorine is mainly produced through the electrolysis of salt. It can be encountered in metallurgy, papermaking, textiles, pharmaceuticals, rubber and plastic production, as well as in the production of phosgene, bleaching powder, and other substances. During the pouring, transportation, and storage of liquid chlorine, as well as when large amounts of chlorine gas escape due to issues such as poor sealing at the cylinder openings, people are often exposed to high concentrations of chlorine. 　　Route of invasion: It primarily invades through the respiratory tract, damaging the upper respiratory tract; it also penetrates deeper into the respiratory tract when the chlorine concentration in the air is high. 　　Introduction to Toxicology Human inhalation LC50: 500 ppm/5 min. 　　Rat inhalation LC50: 293 ppm/1h. Mouse inhalation LC50: 137 ppm/1h. 　　Upon inhalation, chlorine primarily affects the trachea, bronchi, bronchioles, and alveoli, causing corresponding lesions, with some of the chlorine being exhaled through the respiratory tract. The human olfactory threshold for chlorine is 0.06 mg/m^3 ； 90 mg/m^3 can cause severe coughing; 120–180 mg/m^3 can lead to toxic pneumonia and pulmonary edema within 30–60 minutes ； At 300 mg/m^3, it can cause fatal damage ； At 3000 mg/m^3, it is life-threatening ； At levels up to 30,000 mg/m^3, even conventional filtering gas masks provide no protection. Mechanism of poisoning: When inhaled, chlorine reacts with moisture in the mucous membranes and respiratory tract to form hydrogen chloride and reactive oxygen species. Hydrogen chloride can cause inflammatory edema, congestion, and necrosis in the upper respiratory tract; neonatal oxygen has a strong oxidizing effect on tissues and can produce ozone that is cytotoxic to cell cytoplasm. Excessively high chlorine concentrations or prolonged exposure can often lead to lesions in the deeper respiratory tract, causing damage to the bronchioles and alveoli, resulting in bronchiolitis, pneumonia, and toxic pulmonary edema. The stimulatory effect causes local smooth muscle spasms, which exacerbate ventilation disorders and worsen the hypoxia condition; in addition, inhalation of high concentrations of chlorine can stimulate the vagus nerve, leading to reflexive cardiac arrest. 　　Clinical manifestations: Acute poisoning is mainly characterized by damage to the respiratory system. 　　a. The onset and progression of the disease are generally quite rapid. 　　b. Pharyngitis, bronchitis, pneumonia, or pulmonary edema may occur, presenting with symptoms such as sore throat, choking cough, a small amount of sputum production, shortness of breath, chest tightness, or pink frothy sputum and difficulty breathing; there may be no obvious positive signs in the lungs, or dry or wet rales may be present. It is sometimes accompanied by symptoms such as nausea and vomiting. 　　c. In severe cases, acute respiratory distress syndrome may occur, characterized by progressive rapid breathing and distress, tachycardia, and refractory hypoxemia that does not respond to conventional oxygen therapy. 　　d. A few patients experience asthmatic episodes, with wheezing and asthmatic sounds in the lungs. 　　e. At extremely high concentrations, it can cause glottic spasm or edema, bronchospasm, or reflexive suppression of the respiratory center, leading to rapid asphyxial death. 　　f. The main complications include secondary pulmonary infections, myocardial damage, as well as pneumothorax and mediastinal emphysema. 　　G.X-ray examination: It may show no abnormalities, or there may be enhanced lung markings on both sides, punctate or patchy shadows with blurred borders, or foggy or butterfly-shaped shadows. 　　h. Blood gas analysis: In patients with more severe conditions, arterial oxygen partial pressure is significantly reduced. 　　i. ECG examination: After poisoning, conditions such as hypoxia, pulmonary hypertension, and autonomic nervous system dysfunction can lead to myocardial damage and arrhythmias. 　　Eye damage: Chlorine can cause acute conjunctivitis, while high concentrations of chlorine gas or liquid chlorine can cause eye burns. 　　Skin lesions: Liquid chlorine or high-concentration chlorine gas can cause acute dermatitis or burns in the areas of the skin that are exposed to it. 　　Treatment: Those who have inhaled the gas should be immediately removed from the area to a place with fresh air, and kept calm and warm. In case of eye or skin contact with liquid chlorine, rinse thoroughly with water immediately. 　　Those who develop symptoms after inhalation should be observed for at least 12 hours, with symptomatic treatment provided. Those who have inhaled a large amount should rest in bed, receive oxygen therapy, and be given nebulized inhalations of albuterol, Ventolin, or 5% sodium bicarbonate combined with dexamethasone. 　　Appropriate oxygen therapy is required in cases of acute poisoning; adrenal glucocorticoids should be used early, in appropriate doses, and for a short period of time ； Maintain airway patency ； For the prevention and treatment of pulmonary edema and secondary infections, see ； 　　Other symptomatic treatments. Total 2 pages: Previous