Dichloromethane is a chlorinated solvent and belongs to the group volatile organic compounds (VOC). Dichloromethane is also called methylene dichloride and is a colourless, volatile liquid with a sweet odour.1
Dichloromethane is used as an industrial solvent and paint thinner. It may also occur in some aerosols and pesticides and is used in the production of photographic film.2 In the past, the substance was used as an inhalation anaesthetic.3 Since 1993 it is prohibited to market consumer products containing dichloromethane in Sweden and using the substance is prohibited since 1996, unless given exemption.4 5
Sources and transportation pathways
Dichloromethane does not occur naturally in the environment.6 The substance is emitted during use within the chemical and pharmaceutical industry.7 Emissions are mainly released to air as the substance evaporates quickly. In air, it undergoes photochemical degradation within a few months. Most dichloromethane that ends up in the environment turns into carbon dioxide. In water, the substance is degraded within a few days, and in soil it binds loosely to soil particles and evaporates thereafter to air. A small part may also travel to the groundwater and small amounts may be present in drinking water. The substance is not likely to accumulate in plants or animals.8
Effects on environment and health
Dichloromethane is not toxic to aquatic systems.9 The effects on terrestrial animals and birds are unknown but the substance is unlikely to bioaccumulate.10 It reacts with ozone, but since it also reacts with other substances in the lower atmosphere it does not affect the ozone layer significantly.11 As a VOC, dichloromethane can be involved in the formation of ground-level ozone. Ground-level ozone may damage vegetation and during episodes of elevated VOC levels, it may cause irritation of the respiratory tract in humans. Dichloromethane is also a greenhouse gas that contributes to the increased greenhouse gas effect12 13. The increased greenhouse gas effect results in an increase of the average temperature on earth, which for example leads to climate change and rising of the sea level.14 15
Inhalation of dichloromethane may cause dizziness and skin contact may cause burning and redness. The substance may be carcinogenic.16 A toxic and corrosive gas or fumes are formed if it is heated or combusted.17
International agreements and regulations
Dichloromethane is regulated by the EU Water Framework Directive (2000/60/EC). The presence of dichloromethane in product is regulated by EU REACH regulation (EC 1907/2006). The UN Protocol on PRTRs and the EU E-PRTR regulation regulate how data on dichloromethane emissions is made available.
As a VOC, dichloromethane is indirectly regulated by the UN Convention on Long-Range Transboundary Air Pollution (CLRTAP) and the UN Framework Convention on Climate Change (UNFCCC), as well as by the EU National Emissions Ceilings Directive (2001/81/EC) and the EU Industrial Emissions Directive (2010/75/EU).