IPCS INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY Health and Safety Guide No. 6 METHYLENE CHLORIDE HEALTH AND SAFETY GUIDE UNITED NATIONS ENVIRONMENT PROGRAMME INTERNATIONAL LABOUR ORGANISATION WORLD HEALTH ORGANIZATION WORLD HEALTH ORGANIZATION, GENEVA 1987 This is a companion volume to Environmental Health Criteria 32: Methylene Chloride Published by the World Health Organization for the International Programme on Chemical Safety (a collaborative programme of the United Nations Environment Programme, the International Labour Organisation, and the World Health Organization) This report contains the collective views of an international group of experts and does not necessarily represent the decisions or the stated policy of the United Nations Environment Programme, the International Labour Organisation, or the World Health Organization ISBN 92 4 154332 9 ISSN 0259-7268 The World Health Organization welcomes requests for permission to reproduce or translate its publications, in part or in full. Applications and enquiries should be addressed to the Office of Publications, World Health Organization, Geneva, Switzerland, which will be glad to provide the latest information on any changes made to the text, plans for new editions, and reprints and translations already available. (c) World Health Organization 1987 Publications of the World Health Organization enjoy copyright protection in accordance with the provisions of Protocol 2 of the Universal Copyright Convention. All rights reserved. The designations employed and the presentation of the material in this publication do not imply the expression of any opinion whatsoever on the part of the Secretariat of the World Health Organization concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. The mention of specific companies or of certain manufacturers' products does not imply that they are endorsed or recommended by the World Health Organization in preference to others of a similar nature that are not mentioned. Errors and omissions excepted, the names of proprietary products are distinguished by initial capital letters. CONTENTS IPCS HEALTH AND SAFETY GUIDE FOR METHYLENE CHLORIDE INTRODUCTION HOW TO USE THE GUIDE 1. PRODUCT IDENTITY AND USES 1.1. Identity 1.2. Physical and chemical properties 1.3. Composition 1.4. Uses 2. SUMMARY AND EVALUATION 2.1. Exposure to methylene chloride 2.2. Uptake, metabolism and excretion 2.3. Effects on animals 2.4. Effects on human beings 3. CONCLUSIONS AND RECOMMENDATIONS 4. HEALTH HAZARDS FOR MAN, PREVENTION AND PROTECTION, EMERGENCY ACTION 4.1. Main hazards for man, prevention and protection, first aid 4.2. Advice to physicians 4.3. Health surveillance advice 4.4. Explosion and fire hazards 4.4.1. Explosion hazards 4.4.2. Fire hazards 4.4.3. Prevention 4.4.4. Extinguishing agents 4.5. Storage 4.6. Transport 4.7. Spillage and disposal 4.7.1. Spillage 4.7.2. Disposal (based on the IRPTC waste disposal file) 5. INTERNATIONAL CHEMICAL SAFETY CARD 6. HAZARDS FOR THE ENVIRONMENT AND THEIR PREVENTION 7. CURRENT REGULATIONS, GUIDELINES, AND STANDARDS 7.1. Exposure limit values 7.2. Specific restrictions 7.3. Labelling, packaging, and transport 7.4. Other measures INTRODUCTION The International Programme on Chemical Safety is responsible for the publication of a series of Environmental Health Criteria documents, each of which assesses the existing information on the relationship between exposure to a specific chemical, mixture of chemicals, or combination of chemicals and physical and biological agents, and man's health and the integrity of the environment. The documents provide guidelines for setting exposure limits consistent with the protection of human health and the environment. To facilitate the application of these guidelines in national chemical safety programmes, "Health and Safety Guides" are being prepared, highlighting the information contained in the documents for those who need to know the health and environmental issues involved, but not the scientific details. The Guides include advice on preventive and protective measures and emergency action. Review and revision of the information in this Health and Safety Guide will take place in due course, and the eventual aim is to use standardized terminology. We should be grateful if you would help by telling us of any difficulties encountered in using the information in this guide. Comments please, addressed to: The Manager International Programme on Chemical Safety Division of Environmental Health World Health Organization 1211 Geneva 27 Switzerland HOW TO USE THE GUIDE All people in the work-place environment should be given the relevant written information in this book, supplemented by a clear, personal explanation to ensure that they are fully aware of the dangers and the current courses of protective and emergency action. The International Chemical Safety Card should be displayed as directed and its contents clearly explained to all working personnel. Medical staff should be fully conversant with the medical information to ensure they can act rapidly and efficiently in an emergency. Posters should be used to give impact to basic safety measures. Further copies of the Health and Safety Guide and, for those requiring more detailed scientific information, the relevant Environmental Health Criteria publication, are available to order. THE INFORMATION IN THIS GUIDE SHOULD BE CONSIDERED AS A STARTING POINT TO A COMPREHENSIVE HEALTH AND SAFETY PROGRAMME 1. PRODUCT IDENTITY AND USES 1.1 Identity Molecular formula: CH2C12 Chemical structure: H ' Cl - C - Cl ' H Common trade names: Aerothene MM; Freon 30; Narkotil; Solaesthin; Solmethine Common synonyms: DCM; dichloromethane; methane dichloride; methylene bichloride; methylene dichloride; methylenum chloratum CAS registry number:75-09-2 Conversion factor 1 mg/m3 = 0.288 ppm 1 ppm methylene chloride = 3.47 mg/m3 at 25°C and 101.3 kPa (760 mm Hg). 1.2 Physical and Chemical Properties Some physical and chemical properties of methylene chloride are given in the Sample International Chemical Safety Card. 1.3 Composition Technical products contain 0.0001-1% of stabilizers. Paint-stripping formulations usually contain about 80% by weight of methylene chloride, often in combination with methanol. 1.4 Uses Methylene chloride is widely used as a solvent and paint remover. It is also used as a blowing agent for polyurethane, as a propellant in aerosols such as insecticides, hair sprays, shampoos, and paints, as a component in fire-extinguishing products, as an insecticidal fumigant for grains, and as a coolant or refrigerant. 2. SUMMARY AND EVALUATION 2.1 Exposure to Methylene Chloride The main route of human exposure is through inhalation. High concentrations of methylene chloride have been measured indoors in the industrial environment and when using methylene chloride as a paint remover. The general population is exposed to much lower levels in the ambient air and in drinking-water and food. It is estimated that about 80% of the world production of methylene chloride is released into the atmosphere, but degradation of the compound by sunlight takes place at a rate that makes accumulation in the atmosphere unlikely. The initial degradation products are phosgene and carbon monoxide, which are transformed into carbon dioxide and hydrochloric acid. When methylene chloride is present in surface water, most of it will evaporate. The compound is readily biodegradable, when oxygen is present, and bioaccumulation seems unlikely. The behaviour of the compound in the soil has yet to be determined. 2.2 Uptake, Metabolism, and Excretion Absorption of liquid methylene chloride via the skin is slow. Methylene chloride is rapidly absorbed via the gastrointestinal tract and crosses the placenta and blood-brain barrier. At exposure levels normally encountered, most of the methylene chloride taken up is degraded to carbon monoxide, and probably carbon dioxide. It is also exhaled unchanged. At higher exposure levels, not all the methylene chloride taken up can be degraded, and some may be stored in adipose tissue. 2.3 Effects on Animals Single oral doses of methylene chloride at 3000 mg/kg body weight and vapour concentrations of 52000 mg/m3 for 6 h have been shown to be lethal for 50% of exposed rats in a population (LD50, LC50, respectively). Thus, according to the scale of Hodge & Sterner, methylene chloride is "slightly toxic" for rats after oral exposure and "practically non-toxic" after inhalation exposure. Methylene chloride has been shown to cross the placental barrier and to accumulate in fetal tissue and breast milk. In one study, designed to assess teratogenic potential, rats and mice were exposed by inhalation to 4340 mg methylene chloride/m3 during days 6-15 of gestation. There was an increased incidence of extra sternebrae in the offspring of mice and an increased incidence of dilated renal pelvis in rat offspring. In the only reproduction study available for review, no reproductive impairment was found when rats were allowed to mate after receiving 125 mg methylene chloride/litre drinking-water for 13 weeks. Methylene chloride is mutagenic in bacteria, fungi, and in the fruit fly. However, the results of most tests on mammalian somatic cells, including human cells, have been negative. Data available to the Task Group were inadequate for assessing whether methylene chloride should be considered carcinogenic for animals and man. However, the Task Group made this evaluation in September, 1983. More recently, results have become available from US NTP inhalation studies on rats and mice. Under the conditions of these studies, there was some evidence that methylene chloride was carcinogenic for male rats, and there was clear evidence that it was carcinogenic for female rats, and male and female mice. Methylene chloride is only slightly toxic for aquatic organisms, concentrations of between 190 and 330 mg/litre being lethal for half the number of organisms (LC50) exposed for 4 days. 2.4 Effects on Human Beings Exposure to methylene chloride can be estimated roughly by the determination of levels in blood or expired air. Exposure may result in elevated carboxyhaemoglobin levels in the blood. However, it should be kept in mind that blood-carboxyhaemoglobin levels can also be affected by exercise or smoking. As the metabolism of methylene chloride is a saturable process, carboxyhaemoglobin levels in blood do not increase linearly with exposure. The normal levels of blood-carboxyhaemoglobin in man are exceeded in non-smoking, resting individuals after inhalation exposure to a methylene chloride concentration of 400 mg/m3 for 7.5 h. The odour recognition threshold for methylene chloride is above concentrations that have resulted in adverse effects and should not be used as a warning signal. Initial, mild adverse effects on behaviour are observed in non-smoking, healthy persons after inhalation of methylene chloride vapour at a concentration of 690 mg/m3 for 1.5-3 h. Impairment of psychomotor performance occurs after a 4-h exposure to 2610 mg/m3. Narcosis occurred following exposure to 69000 mg/m3 for 30 min. Individuals with heart disease may be especially at risk when exposed to methylene chloride, because of the deficiency of oxygen induced by carbon monoxide, bound to haemoglobin. The vapour of methylene chloride is moderately irritating for the eyes and respiratory tract. The liquid may cause severe irritation of skin and eyes. The main chronic effects in human beings are nervous system depression and an elevated carboxyhaemoglobin concentration in the blood. However, no exposure-related increases in subjective symptoms, neurobehavioural effects, motor nerve conduction velocity changes, electrocardiogram changes, or clinical effects were noted in workers exposed for several years to methylene chloride levels of between 260-347 mg/m3, compared with controls. In 2 human epidemiological mortality studies, there was no excess mortality due to cancer compared with control populations. According to a previous evaluation of all available published epidemiological, experimental, and short-term test data, an IARC Working Group concluded that methylene chloride could not be classified with regard to its carcinogenicity for human beings. 3. CONCLUSIONS AND RECOMMENDATIONS Animal experimental data and human epidemiological data are inadequate for assessing whether or not methylene chloride should be considered carcinogenic for animals and man. From: Environmental Health Criteria 32: Methylene Chloride However, in view of recent findings in inhalation studies on rats and mice, which became available after the Task Group meeting, methylene chloride should be regarded as a potential human carcinogen. 4. HEALTH HAZARDS FOR MAN, PREVENTION PROTECTION, EMERGENCY ACTION 4.1 Main Hazards for Man, Prevention and Protection, First Aid Methylene chloride vapour irritates the eyes and respiratory tract. At high levels of exposure, it may produce pulmonary oedema. The compound, which is metabolized to carbon monoxide, affects the central nervous system and induces an increase in the blood-carboxyhaemoglobin content. The liquid is severely irritating to the skin and eyes and can cause corneal damage. It is a potential human carcinogen. The human health hazards associated with certain types of exposure to methylene chloride, together with preventive and protective measures and first aid recommendations are listed in the following table. Patients with ischaemic heart disease are especially at risk. GOLDEN RULES 1. Do not smoke, drink, or eat in the work-place. 2. In case of overexposure, the victim should leave, or be removed from, the contaminated area to fresh air as rapidly as possible. 3. Remove contaminated clothing and shoes and wash with plenty of water and soap. 4. Flush affected eye(s) with water for at least 15 minutes. 4.2 Advice to Physicians No specific antidote is known. Treat symptomatically. Administer oxygen if needed. Do not administer fats, oils, alcohol, epinephrine, or ephedrine. Pay attention to signs of anoxaemia, impending pulmonary oedema, and ischaemia of the heart. Monitor ECG. Treat skin as for a thermal burn. 4.3 Health Surveillance Advice Persons handling methylene chloride should frequently undergo periodic medical examination with emphasis on the functioning of the central nervous system and irritation of the skin and eyes. Monitoring of blood-carboxyhaemoglobin concentrations can give an indication of the extent of exposure. ROUTE HEALTH HAZARDS PREVENTION AND PROTECTION FIRST AID SINGLE EXPOSURE SKIN Irritation by liquid Avoid exposure; wear Remove contaminated clothing protective clothing and gloves and shoes; wash with plenty of water and soap EYES Irritation by both liquid and Wear safety goggles if there is Flush with plenty of water for vapour a possibility of eye contact at least 15 minutes INHALATION Headache; nausea; dullness; Avoid exposure; apply Victim should be removed to dizziness; irritation of respiratory ventilation, local exhaust, or fresh air and kept quiet; tract with severe overexposure; breathing protection by a administer oxygen, if needed; if effects on the central nervous suitable respirator breathing has stopped, apply system, such as behavioural artificial respiration disturbances, fatigue, weakness, Do not depend on odour to headache, pulmonary oedema, warn of overexposure unconsciousness, death; hypoxia induced by elevated blood-carboxyhaemoglobin content may be hazardous for persons with heart disease or anaemia INGESTION See inhalation Do not eat, drink, or smoke Rinse mouth; give plenty of when handling methylene water to drink (no fats, oils, chloride milk); induce vomiting in conscious patients ROUTE HEALTH HAZARDS PREVENTION AND PROTECTION FIRST AID GENERAL Potential human carcinogen REPEATED EXPOSURE INHALATION Irritation of eyes and respiratory Avoid exposure; apply tract; effects on central nervous ventilation or local exhaust; system, which may be permanent; good public health policy elevated blood-carboxyhaemoglobin would suggest that particular content attention should be paid to pregnant or nursing women 4.4 Explosion and Fire Hazards 4.4.1 Explosion hazards Methylene chloride may react explosively with light metals (lithium, sodium, potassium, aluminium, magnesium) as well as with alloys of sodium. Explosive mixtures are formed with dinitrogen tetroxide (N2O4), dinitrogen pentoxide (N2O5), nitric acid, and compressed oxygen. 4.4.2 Fire hazards Methylene chloride is flammable in an atmosphere with an increased oxygen content. In pure oxygen, the flammable limits (explosive limits) are 15.5 and 66.4%. Methylene chloride is also flammable if small amounts of combustible material are added. The compound decomposes in contact with open flames and glowing surfaces with the formation of harmful gases, such as hydrogen chloride, which forms mists of hydrochloric acid with moisture, and phosgene. 4.4.3 Prevention Do not use methylene chloride in the vicinity of a fire, a hot surface (e.g., a portable heating unit), or during welding. Do not smoke. Do not add any combustible material to methylene chloride. Avoid using compressed oxygen when handling methylene chloride. Avoid contact between the compound and light metals, alloys of light metals, dinitrogen tetroxide, dinitrogen pentoxide, nitric acid, or liquid oxygen. In case of fire, keep drums cool by spraying with water. 4.4.4 Extinguishing agents Carbon dioxide, powder, foam. 4.5 Storage Methylene chloride can react with iron, some stainless steels, copper, nickel, aluminium, and other metals. Rubber and polyvinyl chloride are not resistant to the compound. Methylene chloride can be stored in air-tight containers made of plain, galvanized, or lead-lined, mild steel, or glass. Store in well-labelled containers away from metals and foodstuffs, in cool, dry areas with ventilation across the floor, under shaded conditions away from radiant heat. 4.6 Transport Methylene chloride can be transported in plain, galvanized, or lead-lined, mild steel air-tight containers. 4.7 Spillage and Disposal 4.7.1 Spillage Areas with spills should be evacuated and well ventilated. Collect leaking liquid in a sealable container. Absorb spilled liquid in sand or other inert absorbent and remove to a safe place. Neutralize the remainder with chlorine bleaching liquor. Ensure personal protection by wearing self-contained breathing apparatus. 4.7.2 Disposal (based on the IRPTC waste disposal file) Incineration, preferably after mixing with a combustible fuel. Assure complete combustion to prevent formation of phosgene. An acid scrubber is necessary to remove haloacids produced. The haloacids can be recovered from waste gases and reused. 5. INTERNATIONAL CHEMICAL SAFETY CARD This card should be easily available to all health workers concerned with, and users of, methylene chloride. It should be displayed at, or near, entrances to are where there is potential exposure to methylene chloride, and on processing equipment and containers. The card should be translated into the appropriate language(s). All persons potentially exposed to the chemical should also have the instructions on the chemical safety card clearly explained. SAMPLE INTERNATIONAL CHEMICAL SAFETY CARD METHYLEN CHLORIDE (DCM, dichloromethane, methylene dichloride) (CH2Cl2) PHYSICAL PROPERTIES OTHER CHARACTERISTICS Relative molecular mass 84.93 Colourless liquid with a chloroform-like Appearance colourless liquid odour; the compound decomposes in contact Odour chloroform-like with open flames and glowing surfaces Odour perception threshold 743 mg/m3 with formation of harmful gases; explosive Melting point (°C) -95 mixtures may be formed with light metals, Boiling point (°C) 40 nitric acid, compressed oxygen, N2O4, and Solubility in water (20°C) 20 g/litre N2O5; methylene chloride is flammable only Density (20°C) 1.33 g/ml if the oxygen content of the atmosphere is Relative vapour density 2.93 increased or if small amounts of Vapour pressure (20°C) 46.52 kPa (349 mm Hg) combustible material are added Flammable limits in pure oxygen (%) 15.5-66.4 Octanol/water partition coefficient 1.25 Surface tension 28.12 dyne/cm (20°C) HAZARDS/SYMPTOMS PREVENTION AND PROTECTION FIRST AID SKIN: Irritation; redness Avoid exposure; wear Remove contaminated clothing; wash skin with protective clothing and gloves plenty of water EYES: Irritation; redness Wear safety goggles if there Flush eyes with plenty of water for at is a possibility of eye contact least 15 min. SAMPLE INTERNATIONAL CHEMICAL SAFETY CARD (cont'd). PHYSICAL PROPERTIES OTHER CHARACTERISTICS INHALATION: Headache, nausea, Avoid exposure by use of Fresh air, rest; if breathing has stopped, dullness, dizziness, pulmonary ventilation, local exhaust, or apply artificial respiration; administer irritation; with severe overexposure, breathing protection oxygen, if required; in serious cases, seek effects on the central nervous system, medical attention immediately and pulmonary oedema INGESTION: An unlikely Do not eat, drink, or smoke Rinse mouth; give plenty of water to occupational hazard; abdominal pain; when handling the drink (no fats, oils, milk); do not induce effects on the central nervous system compound vomiting in conscious patients GENERAL: The use of alcoholic beverages enhances toxic effects; potential human carcinogen SPILLAGE STORAGE FIRE AND EXPLOSION Collect leaking liquid in sealable Store in shaded conditions, Not flammable under ordinary conditions; containers; absorb spills in sand or away from radiant heat, in avoid using compressed oxygen; keep away other inert absorbent and remove labelled air-tight containers, from combustible materials; in case of fire, to a safe place; neutralize the made of plain, galvanized or keep drums cool by spraying with water; remainder with chlorine bleaching lead-lined; mild steel or toxic decomposition products may be liquor; take care of personal glass; store separate from generated protection (use of self-contained metals and foodstuffs; breathing apparatus) ventilation across the floor SAMPLE INTERNATIONAL CHEMICAL SAFETY CARD (cont'd). PHYSICAL PROPERTIES OTHER CHARACTERISTICS WASTE DISPOSAL Waste should be incinerated, National Occupational UN: 1593 preferably after mixing with a Exposure Limit: combustible fuel; assure complete National Poison Control combustion; apply acid scrubbing Centre:Note: In cases with adverse health effects, always call a doctor or transport to hospital. Methylene chloride may elevate the blood-carboxyhaemoglobin content and may therefore be extra hazardous for persons with heart disease and anaemia. Pregnant and nursing women should be particularly careful. Do not use the compound in the vicinity of a fire, a hot surface, or during welding. Do not smoke. Do not depend on odour as a warning of overexposure. 6. HAZARDS FOR THE ENVIRONMENT AND THEIR PREVENTION Methylene chloride has a low toxicity for aquatic organisms. Avoid contamination of soil, water, and the atmosphere by using proper methods of storage, transport, handling, and waste disposal. In case of spillage, use the methods advised in section 4.7. Losses to the atmosphere can be minimized by the use of adsorption techniques using activated carbon. 7. CURRENT REGULATIONS, GUIDELINES, AND STANDARDS The information given in this paragraph has been extracted from the International Register of Potentially Toxic Chemicals (IRPTC) legal file. The reader should be aware that regulatory decisions about chemicals taken in a certain country can only be fully understood in the framework of the legislation of that country. A full reference to the original national document from which the information was extracted can be obtained from the IRPTC.a When no effective date appears in the IRPTC legal file, the year of the reference from which the data are taken is shown, indicated by (r). 7.1 Exposure Limit Values See following table. 7.2 Specific Restrictions In Kenya, methylene chloride is a permitted food additive as a solvent. Food products in or on which it is permitted and maximum levels of use are listed (1978 (r)). The European Community legislation allows the presence of methylene chloride, in cosmetic products for marketing, only at concentrations below 35% in the final product. In the case of aerosol preparations, the mandatory label must state "Aerosol: No spraying on naked flame or incandescent material". 7.3 Labelling, Packaging, and Transport The European Community legislation requires labelling as a dangerous substance using the symbol:
a International Register of Potentionally Toxic Chemicals, Palais des Nations, 1211 Geneva 10, Switzerland (Telephone No. 988400-985850). The label must read: harmful by inhalation - avoid contact with skin. The European Community legislation on labelling solvent preparations classifies methylene chloride in Class II d for the purpose of determining the label on solvent preparations containing this substance. The United Nations Committee of Experts on the Transport of Dangerous Goods classifies methylene chloride as a poisonous substance (Class 6.1) with minor danger for packaging purpose (Packing Group III). Packaging methods and label are recommended (1982 (r)). The International Maritime Organization also classifies methylene chloride as a poisonous substance (Class 6.1) and recommends package, storage, and labelling methods for maritime transport in glass bottles, cans, and drums. It is stressed that phosgene fumes are formed when methylene chloride is involved in a fire and that storage should be under shaded conditions, away from radiant heat (1977 (r)). The label recommended by both organizations is:
7.4 Other Measures The European Community legislation on the discharge of dangerous substances into the aquatic environment prohibits the discharge of methylene chloride into groundwater. For other waters, it requires that national authorities give specific discharge authorizations with discharge conditions (total quantity and concentrations). SOME EXPOSURE LIMIT VALUESa Medium Specification Country/ Exposure limit description Value Effective organization date AIR Occupational Australia Threshold limit value (TLV) 1983 (r) -- Time-weighted average 720 mg/m3 Belgium Threshold limit value (TLV) 720 mg/m3 Czechoslovakia Maximum allowable concentration (MAC) 1985 -- Time-weighted average 500 mg/m3 -- Ceiling value 2500 mg/m3 Finland Maximum permissible concentration (MPC) 1982 (r) -- Time-weighted average 1740 mg/m3 German Democratic Maximum allowable concentration MAC 1983 (r) Republic -- Time-weighted average 500 mg/m3 -- Short-term exposure limit (STEL) 1500 mg/m3 Germany, Federal Biological tolerable value (BAT) 1985 (r) Republic of -- Blood-carboxyhaemoglobin at end of shift 5% CO-Hb Germany, Federal Maximum work-site concentration (MAK) 1985 (r) Republic of -- 8-h time-weighted average 360 mg/m3 -- 30-min short-term exposure limit (STEL), 1800 mg/m3 2 × per shift (average value) Hungary Maximum allowable concentration (MAC) 1978 (r) -- Time-weighted average 50 mg/m3 -- Short-term exposure limit (STEL) (30 min) 250 mg/m3 SOME EXPOSURE LIMIT VALUESa (cont'd). Medium Specification Country/ Exposure limit description Value Effective organization date Italy Threshold limit value (TLV) 360 mg/m3 Japan Maximum allowable concentration (MAC) 1984 -- Time-weighted average 360 mg/m3 Netherlands Maximum limit 1985 (r) -- Time-weighted average 700 mg/m3 -- Intended time-weighted average 350 mg/m3 -- Short-term exposure limit (STEL) 1765 mg/m3 Poland Maximum Permissible Limit (MPC) 1982 (r) -- Ceiling value 50 mg/m3 Romania Maximum Permissible Limit (MPC) 1975 (r) -- Time-weighted average 500 mg/m3 -- Ceiling value 700 mg/m3 Switzerland Maximum work-site concentration (MAK) 1984 (r) -- Time-weighted average 360 mg/m3 AIR Occupational Sweden Hygienic limit value (HLV) 1985 -- One day time-weighted average 250 mg/m3 -- Short-term exposure limit (STEL) (15 min) 500 mg/m3 United Recommended limits 1985 (r) Kingdom -- Time-weighted average 700 mg/m3 -- Short-term exposure limit (STEL) (10 min) 870 mg/m3 SOME EXPOSURE LIMIT VALUESa (cont'd). Medium Specification Country/ Exposure limit description Value Effective organization date USA (ACGIH) Threshold limit value (TLV) 1984 (r) -- Time weighted average 360 mg/m3 Short-term exposure limit (STEL) 1700 mg/m3 (intended to be deleted) USA (OSHA) Permissible exposure limit (PEL) 1981 (r) -- Time-weighted average 1736 mg/m3 -- Ceiling value 3472 mg/m3 -- Peak concentration (5 min in any 2-h period) 6945 mg/m3 USSR Maximum allowable concentration (MAC) 1977 -- Ceiling value of vapour 50 mg/m3 Yugoslavia Maximum allowable concentration (MAC) 1971 (r) -- Time-weighted average 500 mg/m3 AIR Ambient Czechoslovakia Maximum allowable concentration (MAC) 1975 (r) (Immission -- Average per day 1.0 mg/m3 standard) -- Average per 0.5 h 3.0 mg/m3 USSR Maximum allowable concentration (MAC) 1984 -- One time per day 8.8 mg/m3 WATER Surface USSR Maximum allowable concentration (MAC) 7.5 mg/litre 1983 SOME EXPOSURE LIMIT VALUESa (cont'd). Medium Specification Country/ Exposure limit description Value Effective organization date FOOD FAO/WHO Acceptable daily intake (ADI) none allocated 1971 USA Maximum permissible concentration (MPC) 1981 -- In spice oleoresins 30 mg/kg -- In hops extract 2.2% (wt/wt) -- In decaffeinated coffee 10 mg/kg -- In food additive modified hop extract 5-150 mg/kg -- In specified food colour additives 30 mg/kg FOOD Plant USA Exempted from tolerance requirements when used 1981 Animal as a fumigant after harvest for certain specified plant products, when used according to good agricultural practice as inert ingredient of pesticides for some specified purposes a TWA = time-weighted average over one working day (usually 8 h).
See Also: Toxicological Abbreviations Methylene chloride (EHC 164, 1996, 2nd edition) Methylene chloride (EHC 32, 1984, 1st edition) Methylene chloride (PIM 343)