Route of invasion: inhalation, ingestion, percutaneous absorption.
Health Hazards:This product has anesthetic effects and mainly damages the central nervous and respiratory systems. The main route of human exposure is inhalation. High concentrations of methylene chloride have been measured in indoor manufacturing environments when used as a paint stripper. Doses to the general population through exposure to ambient air, drinking water and food are much lower. It is estimated that about 80% of the world production of methylene chloride is released into the atmosphere, but the rapid rate of photolysis of the compound makes it unlikely to accumulate in the atmosphere. The initial degradation products are phosgene and carbon monoxide, which are then converted to carbon dioxide and hydrochloric acid. When methylene chloride is present in surface water, most of it will evaporate. When oxygen is present, it is readily biodegradable, and thus bioaccumulation seems unlikely. However, its behavior in soil has yet to be determined.
Health Hazard Effects:
Acute: 1. Slight irritation of nose and throat.
2. At 500 to 1,000 ppm for 1 to 2 hours may cause mild depression of the central nervous system, such as: dizziness, lightheadedness, nausea, numbness of the arms and legs, fatigue, inability to concentrate and reduced coordination.
3. Very high levels of exposure may result in loss of consciousness and death.
Skin: 1. Liquid can irritate skin.
2. May cause severe irritation if it gets inside gloves, shoes or tight clothing.
Eyes: 1. Liquid and highly concentrated vapors may cause irritation.
2. Liquids may cause transient irritation of the cornea.
Inhalation: 1. In animal studies, methylene chloride is rapidly absorbed into the body causing moderate toxicity, as indicated by inhalation.
Chronic: 1. Inhalation: at very high concentrations, it can cause liver and kidney damage. Brain damage has also been reported from repeated exposure to 500-3,600 ppm.
Peak carcinogenicity: three studies indicate that long-term exposure of workers did not show signs of increased cancer, but IARC classified it as a suspected carcinogen. People's Republic of China **** and the country's national occupational health standards GBZ2.1-2007 workplace hazardous factors occupational exposure limits for chemical hazardous factors
Dichloromethane time-weighted average permissible concentration of PC-TWA 200mg/m3. Portable gas chromatography; water quality test tube method; gas detection tube method
Gas tachyphylaxis tubes (products of the German company Dr?ger)
Laboratory Monitoring Methods:
Monitoring Methods Source Category
Gas Chromatography Methods for the Determination of Hazardous Substances in the Air (Second Edition), edited by Hang Shiping Air
Blowing Capture-Gas Chromatography, China Environmental Monitoring Terminal, China Water
Gas Chromatography Methods, Manual of Testing and Analyzing and Evaluating of Solid Waste, China Environmental Monitoring Terminal and others. General Station of Environmental Monitoring, China Solid Waste
Gas Chromatography Analysis of Organic Compounds in Municipal and Industrial Wastewater, translated by Wang Ke'ou, et al. Wastewater
Column Chromatography/Mass Spectrometry Method EPA524.2 Water Quality Former USSR Maximum Permissible Concentration (MPC) of Hazardous Substances in Workshop Air 50mg/m3
China (to be promulgated) MPC of Hazardous Substances in Drinking Water Sources 0.02mg/L China (to be promulgated) 0.02mg/L
China (GHZB1-1999) Environmental Quality Standard for Surface Water (Class I, II, III waters) 0.005mg/L
Former Soviet Union (1975) Maximum Permissible Concentration of Hazardous Substances in Water Bodies 7.5mg/L
Japan (1993) Environmental Standard (mg/L) Surface Water: 0.002
Wastewater: 0.02Soil leachate: 0.002
Olfactory Threshold Concentration 150ppm I. Emergency Response to Leakage
Rapidly evacuate people from the leaking contaminated area to a safe area and isolate them, and strictly limit the entry and exit. Cut off the source of fire. It is recommended that emergency personnel wear self-contained positive pressure air respirators. And utilize restricted spaces such as sewers and flood drains. Small amount of leakage: Adsorb or absorb with sand or other non-combustible materials. Large amount of leakage: construct a dike or control pit to shelter.
Waste disposal method: It is recommended to dispose by incineration. Waste materials mixed with other fuels and incineration, combustion should be sufficient to prevent the generation of phosgene. The nitrogen oxides in the incinerator exhaust are removed by an acid scrubber.
Two, protective measures
Respiratory protection: when the concentration in the air exceeds the standard, you should wear a direct-type gas mask (half mask). Wear an air respirator when rescuing or evacuating from an emergency situation.
Eye protection: If necessary, wear chemical safety glasses.
Body protection: wear anti-poison penetration work clothes.
Hand protection: wear chemical resistant gloves.
Others: Smoking, eating and drinking are prohibited at the work site. After work, shower and change clothes. Store contaminated clothes separately, wash and prepare for use. Pay attention to personal hygiene.
Three, first aid measures
Skin contact: remove contaminated clothing, wash the skin thoroughly with soap and water.
Eye contact: Lift eyelids and flush with running water or saline. Seek medical attention.
Inhalation: Remove quickly from scene to fresh air. Keep airway open. If breathing is difficult, give oxygen. If breathing stops, immediately perform artificial respiration. Seek medical attention.
Feeding: 1. If the patient is about to lose consciousness, has lost consciousness or is in spasm, do not feed anything by mouth.
2. Do not induce vomiting.
3. Give the patient 250 ml of water to drink to dilute the contents of the stomach.
4. If the patient vomits spontaneously, lean him/her forward to minimize the risk of inhalation and repeat the administration of water.
5. If respiratory arrest occurs, administer artificial respiration immediately by a trained person, and perform cardiopulmonary resuscitation for cardiac arrest.
6. Rapidly transport the patient to an emergency medical unit. Drink plenty of warm water, induce vomiting, and seek medical attention.
MOST IMPORTANT SYMPTOMS AND HAZARDOUS EFFECTS: Very high exposure may cause loss of consciousness, death.
Protection for first responders: Do not use mouth-to-mouth resuscitation when the patient inhales or swallows the toxic substance. Use a one-way pocket mask and other medical equipment to perform resuscitation. Wear Level C protective equipment to provide first aid in a safe area.
Fire extinguishing methods: Fog water, sand, foam, carbon dioxide. Extinguishing measures Applicable extinguishing agents: chemical dry powder, foam, carbon dioxide, water mist
Special hazards that may be encountered when extinguishing a fire: 1. above 120 degrees Celsius, the vapors are flammable. 2. toxic gases are decomposed during a fire, which is hazardous.
Special fire-fighting procedures: 1. Sprinkle water to cool containers exposed to the fire, and spray water to wash away leaking material from the exposed area.
2. When such a substance is on fire or trapped in a fire: do not extinguish the fire unless its flow can be stopped. If the fire cannot be controlled or the container is exposed to fire, the area within a 2500-foot radius must be evacuated.
3. Cool the container with plenty of water until the fire is extinguished. (erg2002)
4. Do not flush water directly on spilled material, splashing may occur (erg2002)
Special Protective Equipment for Firefighters: 1. Toxic Products of Combustion: Products of combustion include toxic gases and vapors (e.g., hydrogen chloride, phosgene, and carbon monoxide).
2. Dichloromethane vapor is heavier than air and can float a considerable distance to the ignition source and then burn back. Precautions for operation and storage
1. Avoid generating droplets during operation and wear appropriate personal protective equipment.
2. Avoid letting the released vapors and droplets enter the air in the working area.
3. Operate in a well-ventilated area and use minimum dosage.
4. Have emergency equipment readily available to extinguish fires and deal with spills.
5. Empty storage containers may still contain hazardous residues.
6. Do not operate near welding, flames or hot surfaces.
7. Store in a cool, dry, well-ventilated place out of direct sunlight.
8. Store away from heat, flame and incompatible materials such as strong oxidizers, strong acids and nitric acid.
9. Store in properly labeled containers.
10. Unused containers and empty drums should be tightly covered.
11. Avoid damage to containers and regularly inspect drums for defects such as breakage or leakage.
12. Containers galvanized or lined with phenolic synthetic resin reduce the possibility of methylene chloride decomposition.
13. Store in limited quantities.
14. Post warning signs at appropriate places.
15. Separate the storage area from employee-intensive work areas and limit access to the area.
16. Use plastic hoses specified for the substance to unload toxic chemicals. (hazardtext)
17. Substances may accumulate static electricity which may cause combustion. （Store in a cool, dry, well-ventilated place out of direct sunlight.
Packaging, storage and transportation: sealed in galvanized iron drums, 250kg per drum, train tankers, cars can be transported. It should be stored in a cold, dark, dry and well-ventilated place, and moisture-proof.
Product index Item index Superior product First grade product Qualified product Mass fraction of dichloromethane/% ≥ 99.95 99.90 99.80 Mass fraction of water/% ≤ 0.010 0.020 0.030 Mass fraction of acid (as HCl)/% ≤ 0.0004 0.0008 Color/Hazen unit (Pt-Co color) ≤ 10 Evaporation residue mass fraction/% ≤ 0.0005 0.0006 ≤ 0.0007 ≤ 0.0007 ≤ 0.0007 ≤ 0.0007 ≤ 0.0007 ≤ 0.0007 ≤ 0.0007 ≤ 0.0007 ≤ 0.0009 ≤ 0.0007 ≤ 0.0008 Mass fraction/% ≤ 0.0005 0.0010 The amount of added stabilizer is not counted as mass fraction of dichloromethane. Personal precautions: 1. Restrict personnel from approaching the contaminated area until it has been completely cleaned up.
2. Make sure cleanup is done by trained personnel.
3. Wear appropriate personal protective equipment.
4. Ventilate the area.
5. Extinguish or remove all sources of ignition.
6. Report to the relevant government safety, health and environmental authorities.
Environmental precautions:
1. Immediately isolate uninvolved persons at least 25-50 feet away in the event of a spill [erg2002]
2. Evacuate persons 100 meters upwind in the event of a large spill. (erg2002)
2. Evacuate personnel up to 800 meters away when a fire is burning [erg2002]
Cleanup method: 1. Do not touch the spill.
2. Avoid spillage into sewers, gutters or confined spaces.
3. Try to stop or minimize the spill as far as safety permits.
4. Contain the spill with sand, soil or other absorbent material that does not react with the spilled material.
5. Small spills: Absorb with absorbent substances that do not react with the spilled material. The contaminated absorbent material is as hazardous as the spill and must be placed in a suitable covered and labeled container and the spill area flushed with water. Small spills can be diluted with large amounts of water.
6. Large spills: construct a dike or dig a pit to contain the spill. Cover with foam to reduce the vapor disaster. Transfer with a pump to a tanker or special collector, recycling or transported to the waste disposal site .
7. Environmental considerations:
A. In soil:
1. Dig a pit, pond, lagoon to contain liquid or solid material.
2. Cover the surface with polyurethane, sandbags and soil.
3. Sprinkle ash in the sky to absorb large amounts of liquid material and make it into powder. (HSDB)
B. Water:
1. Use natural barriers or oil to control the extent of contamination.
2. Re-absorb the controlled substances with water pipes.
3. Use mechanical excavators to remove uncontrolled areas. (HSDB)