Dichloromethane: final report

The pollution prevention (P2) plans for dichloromethane (DCM) have been fully implemented.

P2 planning is a process by which organizations can improve their environmental performance by strategically planning to reduce or eliminate pollution before it is created.

Last updated: January 2010

This P2 planning notice has resulted in reductions in uses and releases of DCM dropped from 900 000 kg in 1995 to 60 000 kg by the end of the P2 plan implementation period.

The overall reduction objective of 85% targeted by this notice was exceeded through the replacement of DCM with alternatives, the reformulation of products and other pollution prevention methods.

Information reported for the notice

A pollution prevention planning notice targeting 5 sectors was developed, setting out risk management objectives for industrial sectors. Environment and Climate Change Canada's risk management objective was to reduce aggregate DCM releases from the 5 targeted industry sectors by 85% from 1995 base year levels by January 1, 2007.

On November 29, 2003, the Minister of the Environment published a notice requiring the preparation and implementation of pollution prevention plans in respect of DCM in Part I of the Canada Gazette. This notice targets persons who use DCM in the activities shown in Table 1.

Pollution prevention methods

The replacement of DCM with alternatives and product reformulation accounted for 60% of the pollution prevention methods used to reduce DCM use and releases.

Although the targeted industry sectors had different risk management objectives, several of the reported P2 methods were common across all sectors. The most common P2 methods reported were material or feedstock substitution and product reformulation. Furthermore, several companies indicated that they would eliminate DCM from their operations completely. The figure below shows the methods used to achieve the objectives identified in the P2 notice.

Chart 1: P2 methods selected by the targeted sectors

Overall achievements of the notice

The results indicate that the risk management objective of reducing aggregate releases of DCM from the 5 targeted industry sectors by 85% from the 1995 base year levels was exceeded. Releases were reduced by 93% compared to 1995 levels.

Although the overall objective was achieved, the results show that 3 of the 5 industry sectors did not achieve their individual risk management objectives: adhesives formulation, aircraft paint stripping, including the stripping of aircraft components, and pharmaceuticals and chemical intermediates manufacturing and tablet coating (see tables 2 and 3).

In the adhesives formulation sector, 2 out of 9 facilities achieved the objective of a 70% reduction in the use of DCM from the 1995 base year level. In most cases, the facilities in that sector that did not achieve the risk management objective reported that the use of DCM is associated with the demand for adhesives and that given the highly competitive nature of this industry, they were unable to reduce DCM use by 70%.

In the industrial cleaning, at the end of implementation of the P2 plan, 6 facilities out of 9 achieved the risk management objective of reducing the releases of DCM by 80%.

In the aircraft paint stripping sector, the risk management objective was achieved and exceeded by 6 facilities out of 9. All facilities reduced their releases except for one facility that increased its releases by 155%.

In the flexible polyurethane foam blowing sector, all facilities met the risk management objective of reducing the releases of DCM by 100%.

With respect to the pharmaceuticals and chemical intermediates manufacturing and tablet coating sector, only 1 facility reduced its DCM releases by 90% from the 1995 base year level. Those facilities that did not achieve the reduction objective indicated that they were unable to achieve the objective due to increase in demand for DCM-based products, and to the impossibility of replacing DCM with another solvent due to contractual obligations. However, the recovery rate (which represents the difference between the quantity of DCM used and the quantity released) reached 90% in 2004.

Next steps

Environment and Climate Change Canada is examining the need to develop additional risk management measures to protect the environment and health of Canadians from risks associated with DCM.

Background

DCM, also known as methylene chloride, is a versatile solvent used in a variety of industrial applications. It is also the active chemical in paint stripping and cleaning formulations. DCM is a clear, colourless liquid with a mildly sweet odour. DCM is a versatile solvent used in a wide range of industrial process applications, such as industrial cleaning and the manufacturing of pharmaceuticals, plastics and flexible polyurethane foam, and in industrial, commercial and household paint strippers.

Entry into the environment

DCM is not produced in Canada. The quantity of DCM imported and used in Canada each year between 1995 and 2007 fell from 13.1 to 3.2 kilotonnes (SRI Consulting, Chemical Economics Handbook, Chlorinated Methanes). There are no known natural sources of DCM. Due to its volatility and the dispersive nature of its uses, the majority of DCM used is released into the environment, primarily to the atmosphere. Entry may also occur from waste disposal sites, industrial effluents and water treatment facilities.

The effects of dichloromethane on the environment and on human health

DCM was assessed as toxic under the 1988 Canadian Environmental Protection Act (CEPA), based on its potential to cause harm to the environment and to human health. The assessment report published in 1993 stated that although DCM was entering into the environment in significant quantities, it generally did not occur in concentrations that would be expected to cause adverse effects on terrestrial wildlife; however, there are limited data suggesting that concentrations of DCM in water may be sufficient to cause adverse effects on some aquatic organisms. Also, DCM has been classified as being "probably carcinogenic to humans," and it may enter the environment in quantities or under conditions that may constitute a danger in Canada to human life or health. It can also cause skin irritations. Inhalation of DCM vapours can cause sluggishness, light-headedness, irritability, nausea and headaches, depending on the amount inhaled.