Hazards of phosgene
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Dear sea friends, what is phosgene? What are the harms to the human body?
Well, haha. Baidu will do. It’s my first time hearing about this, so please forgive me. I just checked Baidu; it has quite detailed information. I’m sorry, it’s sixth grade now. I’m very sorry; my internet connection isn’t very good~~~ Please understand. This post was last edited by Fightinghard on 2009-3-16 at 10:57.]
Phosgene is known in Chinese as carbonyl chloride; its molecular formula is COCl2. Health hazards: It primarily damages the respiratory tract, causing chemical bronchitis, pneumonia, and pulmonary edema. Acute poisoning: In cases of mild poisoning, patients experience tearing, photophobia, discomfort in the throat, coughing, and chest tightness ； In moderate poisoning, in addition to the exacerbation of the aforementioned symptoms, the patient experiences mild difficulty breathing and mild cyanosis ； In severe poisoning, pulmonary edema or adult respiratory distress syndrome occurs; the patient experiences severe coughing, production of large amounts of frothy sputum, respiratory distress, and significant cyanosis. There is a period of symptom relief before the onset of pulmonary edema (usually 1–24 hours). Mediastinal and subcutaneous emphysema can occur concurrently.
It is a highly dangerous toxic gas that causes acute damage, primarily to the lungs. Phosgene is used in TDI production.
There is certainly danger in producing this, as leaks can occur. With good equipment conditions and appropriate emergency measures in place, safe production can still be achieved.
Is phosgene really being produced upstairs? The concentration of phosgene in the atmosphere is not high enough to cause leaks; the allowable concentration of it in the atmosphere is extremely low.
\"Occupational Exposure Limits for Hazardous Factors in the Workplace – Chemical Hazardous Factors\", GBZ 2.1-2007: the MAC (maximum allowable concentration in the air) is 0.5 mg/m3, which is a quite high level of toxicity. It was used as a chemical weapon during World War II. The phosgene process used in TDI production is a relatively outdated method, and it is no longer used abroad. Storage is generally not allowed at the production site; materials are used as they are produced, with at most a buffer tank available
Phosgene is a highly toxic and corrosive gas; in case of an emergency, its toxicity and corrosiveness (as it releases hydrogen chloride when in contact with water) will be the main factors to consider in disaster relief efforts. I. Material Identification Table
Item | Content | Synonyms
--- | --- | ---
Dichloro carbon | Carbon Oxychloride, Carbonic Dichloride, Carbonyl Chloride, Chloroformyl Chloride |
Chemical formula | COCl2 |
CAS Number | 75-44-5 |
UN Number | 1079 |
Hazard classification | Toxic gas, corrosive substance |
II. Physical, Chemical Properties and Hazard Information
Phosgene is a stable, non-flammable, highly toxic corrosive gas. Its key properties are as follows:
1. Physical properties table
Item | Property information |
--- | --- |
Color | Colorless |
State | Gas |
Odor | Similar to mold odor; strong suffocating smell at high concentrations; mild, sweet, grass-like odor at low concentrations. Boiling point: 8.2°C, Specific gravity: 1.432 (0°C) ； 1.37 (at 20°C); Vapor pressure: 1215 mmHg (at 20°C); Vapor density: 3.4 (air = 1, at 20°C). Solubility in water: It decomposes in water to form CO2 and HCl. 2. Chemical properties table: Item; Chemical property details. Corrosivity: Pure gas is not corrosive to carbon steel; however, when it reacts with vapor to produce carbon dioxide and hydrogen chloride, it becomes corrosive. Liquid phosgene can corrode certain plastics, rubbers, and coatings. Polymerization: No harmful polymerization occurs. Reactivity and Incompatibilities (1) Upon contact with water or water vapor, it reacts to produce toxic and corrosive gases (i.e., hydrogen chloride gas). (2) Sodium gas and phosgene react at 260°C to emit light. (3) Aluminum powder burns in phosgene. (4) A mixture of potassium and phosgene can explode if shaken. (5) Isopropanol reacts with phosgene to form isopropyl chloroformate and hydrogen chloride ； In the presence of iron salts, thermal decomposition occurs, which can sometimes lead to explosions. Decomposability: It decomposes at 550°C. 3. Disaster Data Sheet – Items: Disaster-related data; Flash point: Non-flammable. 4. Health Hazard Data Sheet – Items: Health hazard information; Permissible concentration: 0.1 ppm, 0.4 mg/m3; Animal LD50; Animal LC50: 1,400 mg/m3 (30 minutes, rats, inhalation); Immediate Danger Limit (IDLH): 2 ppm; Carcinogenicity classification: None. III. Disaster Prevention Equipment: For dealing with phosgene in disaster situations, appropriate preventive equipment must be selected to ensure personnel protection and control of leaks: 1. Personal protective equipment – Scope of use: Areas where the gas concentration is 2 ppm or higher, or in situations where the concentration is unknown. Level A protective clothing, including: (1) Airtight full-body protective suit; (2) Positive-pressure self-contained breathing apparatus (placed inside the protective suit); (3) Protective gloves (made of Teflon); (4) Protective shoes/boots. For areas where the gas concentration is below 2 ppm and the oxygen concentration in the air is above 19.5%. Class C protective clothing and equipment, including: (1) Non-airtight coveralls; (2) Full-face or half-face air-filtering masks (for phosgene use); (3) Protective gloves (made of Teflon); (4) Protective shoes/boots. 2. Detection and alarm equipment: Object of detection, Equipment, Detection range, Toxicity concentration – Portable electrochemical detectors: 0–1 ppm; Portable colorimetric detectors: 0–5 ppm; Fixed electrochemical detectors: 0–1.5 ppm. Flammability concentration – Portable or fixed flammable gas detectors: 0–100% LEL. Note: In accordance with Article 18, Article 20, and Item V–(II) of Announcement No. 31061 issued by the Environmental Protection Administration under the Detailed Rules for the Implementation of the Law on the Management of Toxic Chemical Substances, detection and alarm equipment must be installed in facilities where phosgene is handled. IV. Symptoms of poisoning Phosgene can cause poisoning in the human body through inhalation and skin contact; it is irritating to the eyes, nose, and throat. Symptoms of poisoning include irritation, pulmonary edema, coughing, breathing pain, and even death. 1. Symptoms of inhalation poisoning: Exposure level, symptoms of poisoning – 3 ppm: throat irritation; 4 ppm: eye irritation; 4.8 ppm: causes coughing; 50 ppm: rapidly fatal. 2. Symptoms of skin contact poisoning: Contact with the liquid can cause severe burns. 3. Symptoms of eye contact poisoning: Exposure to the gas at a concentration of 1–2 ppm causes itching and a burning sensation in the eyes, while higher concentrations seem to lead to tearing and conjunctivitis. V. First aid measures: Those who attempt to rescue victims of phosgene poisoning must wear the full set of personal protective equipment specified in the aforementioned disaster relief equipment before entering the affected area to save people. In the emergency treatment of phosgene poisoning, the most important thing is to quickly move the patient away from the scene to a well-ventilated area, examine the patient’s symptoms of poisoning, determine the route of exposure, and provide appropriate first aid (see Figure 16.1). 1. Basic principles for first aid in poisoning – Examination items, First aid principles: Eyes, breathing, heartbeat. (1) Regardless of whether the poisoning is due to inhalation or contact, 100% oxygen can be administered first. (2) If the patient is unconscious, place them in the recovery position and do not feed them. (3) If breathing and heartbeat have stopped, perform cardiopulmonary resuscitation (CPR) immediately. (4) Immediately ask someone to help call 119 for assistance. (5) Take to the hospital immediately and inform them of exposure to phosgene. (6) Until the rescue personnel arrive, handle it in accordance with items 2, 3, 4, and 5 below. 2. First aid for inhalation injuries: Sequence of first aid steps – Immediate measures: (1) Administer 100% oxygen. (2) Immediately ask someone to help make a call for rescue. (3) If breathing stops, perform artificial respiration (mouth-to-mouth resuscitation is not recommended). (4) If the heartbeat stops, perform external chest compressions immediately. Subsequent treatment: Send to the hospital immediately. 3. First aid for skin contact injuries – Sequence of first aid steps: Immediate action (1) If a liquid comes into contact with the skin, immediately wash the affected area with plenty of water. (2) If it penetrates the skin through clothing, immediately remove the clothing and wash with plenty of water. (3) If the stinging sensation persists, continue rinsing with water for at least 15 to 30 minutes. (4) At the end of rinsing, cover the injured area with clean clothing. Subsequent treatment: Send to the hospital immediately. 4. First aid for eye contact injuries – Sequence of first aid steps: Immediate treatment (1) Immediately rinse the eyes with plenty of water for at least 15–30 minutes, keeping the upper and lower eyelids open from time to time. (2) Contact lenses must first be removed or rinsed out with water. (3) Use a moistened cotton swab to remove any removable foreign objects. (4) After rinsing, cover with a clean gauze and secure it with adhesive tape. Subsequent treatment: Send to the hospital immediately. Figure 16.1 Flowchart of emergency first aid procedures before arrival at the hospital due to phosgene poisoning. VI. Assessment of disaster situations and response measures. Situation Response measures Leakage: (1) Upon detection of a leakage, the area within 150 meters around the leak site must be immediately sealed off and isolated. (2) Cut off ignition sources (no smoking, flames, or sparks). (3) Stay in an upwind position and away from low-lying areas. (4) Before entering the hazardous area for observation, it is necessary to fully don the personal protective equipment specified among the aforementioned disaster relief equipment. (5) In the event of a small leak, evacuate the residents within 1 kilometer downwind one by one, starting from the nearest area and moving outward. (6) In the event of a large-scale leak (more than 10 tons), the emergency containment zone should be expanded to 450 meters in all directions, and the evacuation distance should be increased to over 5 kilometers. (7) Depending on the wind conditions and the dispersion rate of the gas cloud, the evacuation distance can be increased to 8.8 kilometers. (8) For larger leaks (over 100 tons), the evacuation distance should be doubled again. VII. Disaster relief methods and post-disaster handling 1. Disaster relief for leaks Severity Method Small amount (1) If the leak can be stopped without any risk, do so immediately. (2) Personal protective equipment from the aforementioned disaster relief equipment must be worn fully. (3) Sprinkling water can reduce vapor volume, but do not spray water directly onto the leak area or inside the container. (4) Rinse the contaminated area with plenty of water. (5) For areas under evacuation control, it must be terminated only after the gas has dispersed and diluted. In large quantities: (1) If the leak can be stopped without any risk, do so immediately. (2) Personal protective equipment from the aforementioned disaster relief equipment must be worn fully. (3) Sprinkling water can reduce vapor volume, but do not spray water directly onto the leak area or inside the container. (4) Build a dike at the front end of the leaking liquid to contain it, pending further treatment and recovery. (5) For areas under evacuation control, it must be terminated only after the gas has dispersed and diluted. 2. Disaster relief in case of a fire in the vicinity (1) Remove the phosgene containers from the fire area as soon as possible. (2) Sprinkle water to cool the walls of the phosgene container exposed to thermal radiation. 3. Post-disaster handling: (1) The area where the leakage occurred needs to be ventilated, and the gases there should then be directed into a gas absorption tower. (2) Small amounts of leaked liquid are absorbed using vermiculite, fine sand, soil, or similar materials. The waste resulting from this absorption is then scooped into appropriate sealed containers, after which the gas is extracted and directed into a gas absorption tower. (3) The large amount of leaked liquid is recovered and treated using a pump. (4) Afterward, ventilate the disaster area and then introduce its gases into the gas absorption tower. (5) Thoroughly clean the disaster area using detergent and water; the resulting wastewater should be directed to a wastewater treatment facility.
Item | Content | Synonyms
--- | --- | ---
Dichloro carbon | Carbon Oxychloride, Carbonic Dichloride, Carbonyl Chloride, Chloroformyl Chloride |
Chemical formula | COCl2 |
CAS Number | 75-44-5 |
UN Number | 1079 |
Hazard classification | Toxic gas, corrosive substance |
II. Physical, Chemical Properties and Hazard Information
Phosgene is a stable, non-flammable, highly toxic corrosive gas. Its key properties are as follows:
1. Physical properties table
Item | Property information |
--- | --- |
Color | Colorless |
State | Gas |
Odor | Similar to mold odor; strong suffocating smell at high concentrations; mild, sweet, grass-like odor at low concentrations. Boiling point: 8.2°C, Specific gravity: 1.432 (0°C) ； 1.37 (at 20°C); Vapor pressure: 1215 mmHg (at 20°C); Vapor density: 3.4 (air = 1, at 20°C). Solubility in water: It decomposes in water to form CO2 and HCl. 2. Chemical properties table: Item; Chemical property details. Corrosivity: Pure gas is not corrosive to carbon steel; however, when it reacts with vapor to produce carbon dioxide and hydrogen chloride, it becomes corrosive. Liquid phosgene can corrode certain plastics, rubbers, and coatings. Polymerization: No harmful polymerization occurs. Reactivity and Incompatibilities (1) Upon contact with water or water vapor, it reacts to produce toxic and corrosive gases (i.e., hydrogen chloride gas). (2) Sodium gas and phosgene react at 260°C to emit light. (3) Aluminum powder burns in phosgene. (4) A mixture of potassium and phosgene can explode if shaken. (5) Isopropanol reacts with phosgene to form isopropyl chloroformate and hydrogen chloride ； In the presence of iron salts, thermal decomposition occurs, which can sometimes lead to explosions. Decomposability: It decomposes at 550°C. 3. Disaster Data Sheet – Items: Disaster-related data; Flash point: Non-flammable. 4. Health Hazard Data Sheet – Items: Health hazard information; Permissible concentration: 0.1 ppm, 0.4 mg/m3; Animal LD50; Animal LC50: 1,400 mg/m3 (30 minutes, rats, inhalation); Immediate Danger Limit (IDLH): 2 ppm; Carcinogenicity classification: None. III. Disaster Prevention Equipment: For dealing with phosgene in disaster situations, appropriate preventive equipment must be selected to ensure personnel protection and control of leaks: 1. Personal protective equipment – Scope of use: Areas where the gas concentration is 2 ppm or higher, or in situations where the concentration is unknown. Level A protective clothing, including: (1) Airtight full-body protective suit; (2) Positive-pressure self-contained breathing apparatus (placed inside the protective suit); (3) Protective gloves (made of Teflon); (4) Protective shoes/boots. For areas where the gas concentration is below 2 ppm and the oxygen concentration in the air is above 19.5%. Class C protective clothing and equipment, including: (1) Non-airtight coveralls; (2) Full-face or half-face air-filtering masks (for phosgene use); (3) Protective gloves (made of Teflon); (4) Protective shoes/boots. 2. Detection and alarm equipment: Object of detection, Equipment, Detection range, Toxicity concentration – Portable electrochemical detectors: 0–1 ppm; Portable colorimetric detectors: 0–5 ppm; Fixed electrochemical detectors: 0–1.5 ppm. Flammability concentration – Portable or fixed flammable gas detectors: 0–100% LEL. Note: In accordance with Article 18, Article 20, and Item V–(II) of Announcement No. 31061 issued by the Environmental Protection Administration under the Detailed Rules for the Implementation of the Law on the Management of Toxic Chemical Substances, detection and alarm equipment must be installed in facilities where phosgene is handled. IV. Symptoms of poisoning Phosgene can cause poisoning in the human body through inhalation and skin contact; it is irritating to the eyes, nose, and throat. Symptoms of poisoning include irritation, pulmonary edema, coughing, breathing pain, and even death. 1. Symptoms of inhalation poisoning: Exposure level, symptoms of poisoning – 3 ppm: throat irritation; 4 ppm: eye irritation; 4.8 ppm: causes coughing; 50 ppm: rapidly fatal. 2. Symptoms of skin contact poisoning: Contact with the liquid can cause severe burns. 3. Symptoms of eye contact poisoning: Exposure to the gas at a concentration of 1–2 ppm causes itching and a burning sensation in the eyes, while higher concentrations seem to lead to tearing and conjunctivitis. V. First aid measures: Those who attempt to rescue victims of phosgene poisoning must wear the full set of personal protective equipment specified in the aforementioned disaster relief equipment before entering the affected area to save people. In the emergency treatment of phosgene poisoning, the most important thing is to quickly move the patient away from the scene to a well-ventilated area, examine the patient’s symptoms of poisoning, determine the route of exposure, and provide appropriate first aid (see Figure 16.1). 1. Basic principles for first aid in poisoning – Examination items, First aid principles: Eyes, breathing, heartbeat. (1) Regardless of whether the poisoning is due to inhalation or contact, 100% oxygen can be administered first. (2) If the patient is unconscious, place them in the recovery position and do not feed them. (3) If breathing and heartbeat have stopped, perform cardiopulmonary resuscitation (CPR) immediately. (4) Immediately ask someone to help call 119 for assistance. (5) Take to the hospital immediately and inform them of exposure to phosgene. (6) Until the rescue personnel arrive, handle it in accordance with items 2, 3, 4, and 5 below. 2. First aid for inhalation injuries: Sequence of first aid steps – Immediate measures: (1) Administer 100% oxygen. (2) Immediately ask someone to help make a call for rescue. (3) If breathing stops, perform artificial respiration (mouth-to-mouth resuscitation is not recommended). (4) If the heartbeat stops, perform external chest compressions immediately. Subsequent treatment: Send to the hospital immediately. 3. First aid for skin contact injuries – Sequence of first aid steps: Immediate action (1) If a liquid comes into contact with the skin, immediately wash the affected area with plenty of water. (2) If it penetrates the skin through clothing, immediately remove the clothing and wash with plenty of water. (3) If the stinging sensation persists, continue rinsing with water for at least 15 to 30 minutes. (4) At the end of rinsing, cover the injured area with clean clothing. Subsequent treatment: Send to the hospital immediately. 4. First aid for eye contact injuries – Sequence of first aid steps: Immediate treatment (1) Immediately rinse the eyes with plenty of water for at least 15–30 minutes, keeping the upper and lower eyelids open from time to time. (2) Contact lenses must first be removed or rinsed out with water. (3) Use a moistened cotton swab to remove any removable foreign objects. (4) After rinsing, cover with a clean gauze and secure it with adhesive tape. Subsequent treatment: Send to the hospital immediately. Figure 16.1 Flowchart of emergency first aid procedures before arrival at the hospital due to phosgene poisoning. VI. Assessment of disaster situations and response measures. Situation Response measures Leakage: (1) Upon detection of a leakage, the area within 150 meters around the leak site must be immediately sealed off and isolated. (2) Cut off ignition sources (no smoking, flames, or sparks). (3) Stay in an upwind position and away from low-lying areas. (4) Before entering the hazardous area for observation, it is necessary to fully don the personal protective equipment specified among the aforementioned disaster relief equipment. (5) In the event of a small leak, evacuate the residents within 1 kilometer downwind one by one, starting from the nearest area and moving outward. (6) In the event of a large-scale leak (more than 10 tons), the emergency containment zone should be expanded to 450 meters in all directions, and the evacuation distance should be increased to over 5 kilometers. (7) Depending on the wind conditions and the dispersion rate of the gas cloud, the evacuation distance can be increased to 8.8 kilometers. (8) For larger leaks (over 100 tons), the evacuation distance should be doubled again. VII. Disaster relief methods and post-disaster handling 1. Disaster relief for leaks Severity Method Small amount (1) If the leak can be stopped without any risk, do so immediately. (2) Personal protective equipment from the aforementioned disaster relief equipment must be worn fully. (3) Sprinkling water can reduce vapor volume, but do not spray water directly onto the leak area or inside the container. (4) Rinse the contaminated area with plenty of water. (5) For areas under evacuation control, it must be terminated only after the gas has dispersed and diluted. In large quantities: (1) If the leak can be stopped without any risk, do so immediately. (2) Personal protective equipment from the aforementioned disaster relief equipment must be worn fully. (3) Sprinkling water can reduce vapor volume, but do not spray water directly onto the leak area or inside the container. (4) Build a dike at the front end of the leaking liquid to contain it, pending further treatment and recovery. (5) For areas under evacuation control, it must be terminated only after the gas has dispersed and diluted. 2. Disaster relief in case of a fire in the vicinity (1) Remove the phosgene containers from the fire area as soon as possible. (2) Sprinkle water to cool the walls of the phosgene container exposed to thermal radiation. 3. Post-disaster handling: (1) The area where the leakage occurred needs to be ventilated, and the gases there should then be directed into a gas absorption tower. (2) Small amounts of leaked liquid are absorbed using vermiculite, fine sand, soil, or similar materials. The waste resulting from this absorption is then scooped into appropriate sealed containers, after which the gas is extracted and directed into a gas absorption tower. (3) The large amount of leaked liquid is recovered and treated using a pump. (4) Afterward, ventilate the disaster area and then introduce its gases into the gas absorption tower. (5) Thoroughly clean the disaster area using detergent and water; the resulting wastewater should be directed to a wastewater treatment facility.
Phosgene is extremely toxic, more so than chlorine.
Since all the brothers and sisters above have explained it so thoroughly, I won’t say anything more. Let’s talk about this: phosgene originates from vehicle exhaust gases, as these gases contain large amounts of sulfur and nitrogen oxides