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Processes and challenges in the substitution of harmful chemicals

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Context - When a chemical substance is identified as harmful, an alternative needs to be found.

It is not an easy process, since it is important to chose an alternative that is technically equivalent while being safer. What are the challenges that are posed by this substitution process ?

This is a faithful summary of the leading report produced in 2016 by the Organization for Economic Co-operation and Development (OECD): " Synthesis Report from the OECD Workshop on Alternatives Assessment and Substitution of Harmful Chemicals " 

  • Source document:OECD (2016)
  • Summary & Details: GreenFacts
Latest update: 30 April 2016


When a chemical substance is identified as harmful, the need to find alternative arises, so that the products and applications that use it can be substituted. It is not an easy process, since it is important to chose an alternative chemical or technology that is safer than the one being substituted. In May 2015, the OECD convened an expert group to identify where gaps remained in terms of possible missing tools, guidance and research to support stakeholders engaged in alternatives assessment and substitution of harmful chemicals.

Is the substitution of chemicals considered a sustainability challenge?

The substitution of dangerous chemicals is now included in both the current strategies to reduce risks of chemicals on human health and the environment as well as into industry’s approach to sustainable development.

However, finding suitable alternatives to chemicals of concern is not a small challenge. Alternatives should be safer, having a lower hazard and risk potential, but still present similar performance to their counterpart and be economically viable and sustainable. Substituting chemicals also goes beyond finding a drop-in chemical alternative and can include systems, materials, or process changes.

Nervertheless the concept of substitution is now increasingly included as part of policy and regulatory measures for the management of chemicals of concern. For example, substitution has become a central element of the European Union REACH regulation and in the United States, a policy approach has been taken by the U.S. Environmental Protection Agency (U.S. EPA) by promoting the use of safer chemicals.

What are the main barriers and challenges to the substitution of dangerous chemicals and what are the drivers?

Various elements have been identified by experts as barriers :

  • There can be a resistance to change, a reluctance to experiment with the unknown, and fears for regrettable substitution; a company’s policy can be a barrier and there can be a lack of engagement to find alternatives to hazardous chemicals.
  • There is a lack of guidance and of clarity on how to conduct a “successful” assessment of potential alternatives, and there is a need for specific training and education in this area.
  • Furthermore, there are technical, administrative and financial constraints associated with conducting alternatives assessment and substituting chemicals, in particular for small and medium-sized enterprises (SMEs) and the complexity of regulatory systems can be a challenge In the case of countries/regions using regulations.

The two main drivers that were identified by experts were:

  • The response to regulatory requirements and more generally the integration of substitution of chemicals of concern as part of the political agenda ;
  • Market drivers that include opportunities for companies to generate new patents, opportunities to respond to green customers’ demands, the creation of a competitive advantage, and the integration of substitution into the corporate strategy of certain companies.

Which initiatives have already been taken to support substitution initiatives?

Over the past decades, several government, industry and NGO initiatives have been supporting the development and use of substitution chemicals.

A large amount of expertise and experience is being generated from past alternatives assessment and substitution cases, and there are efforts ongoing to collect and compile this “real life” experience. It is the objective of the OECD SAAToolbox, which is a first version of such a compilation. It includes a range of resources about chemical substitution and alternatives assessments and practical guidance on conducting them.

The REACH program of the European Union is another valuable resource, that constitutes one of the largest analysis of alternatives in the world and has also showed that substitution does happen. Many industries that are required to register the chemicals that they use, have already switched to alternatives of the substances that were identified as problematic, or indicated that they are in the process of switching.

What are the most challenging issues remaining in this process of substitution of dangerous chemicals?

There are three elements in the substitution process that can be considered as particularly challenging:

  1. the choice of the attributes to be used in the alternatives assessment, according to available knowledge and resources;
  2. how to define when a “successful” alternatives assessment/substitution has been conducted;
  3. the criteria to help manage hazard and risk trade-offs.

To simplify the process, there might be opportunities to develop a minimum set of attributes that companies, in particular SMEs, could easily manage.

Using available tools would allow informed alternatives choices by taking a “full picture” approach for product evaluation, from ingredient disclosure, hazard analysis, exposure assessment, and life-cycle consideration.

A short list of questions would help define whether the alternatives assessment was well conducted and "successful" or if weaknesses remain in some areas. Since the assessement process is complex and that there is a risk for a regrettable substitution where the alternative substance turns out to be more dangerous than the original one, there is the danger of staying stuck in endless analyses rather than to act, once a suitable alternative has been found.

Also, a short set of best practices based on the analysis of case studies and on common current practices would help manage hazard and risk trade-offs.

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