If hazardous chemicals are avoided in products and processes, also hazardous wastes are avoided in the own company and at any later lifecycle stage of the products. This is good, because costs for hazardous wastes are avoided, recycled material is not contaminated, and human health and the environment are better protected from chemical risks.

Chemicals in wastes

Chemicals can become waste or they can be included in wastes. Examples of chemicals that end up in waste streams are:

Used processing auxiliaries from production processes, such as or lubricants
Production wastes, such as paint overspray and sludge from galvanizing baths
Off-cuts or product rejects into which chemicals have been included during production
Ingredients in any type of post-consumer wastes, such as end-of-life electronic or plastic products.

Considering the waste stage of chemicals in risks management

From a company perspective, there are several reasons to consider the waste stage of chemicals in risk management:

Hazardous production wastes require separate collection and detailed documentation. The treatment of hazardous wastes in specialized facilities causes considerable costs;
The generation of hazardous wastes is a significant environmental impact that should generally be reduced, in particular if a company has an environmental management system;
Hazardous substances in products hinder the circular economy as they may be included into secondary materials during recycling.

The use of hazardous chemicals, and thus their content in wastes, cannot always be avoided. However, good risk management can reduce their negative impacts.

Production wastes

Like any other waste, wastes from the use of chemicals in production processes need to be classified according to national legislation, which implements EU requirements. While entries from the so-called list of waste need to be selected, the waste generator must decide whether the waste is hazardous (i.e. shall be marked with an asterisk). An asterisk is needed if hazardous (classified) substances are contained above defined threshold values. Hence, the composition needs to be identified based on information about chemicals in mixtures and articles used in the production.

Some processing auxiliaries can be recovered and recycled after they become production waste, such as solvents that can be absorbed and then cleaned/distilled or lubricants that can be processed for re-use.

Off-cuts or production rejects may be re-introduced into the production processes without extensive pre-treatment. Examples are plastic rejects that are melted and merged with the primary feedstock for re-extrusion, or repulping of off-cuts from paper production.

Production wastes that cannot be easily recycled internally may have to be disposed of. As the composition of such materials or waste products is usually know to the waste generator, information can be provided on hazardous chemicals to the disposal company, enabling it to consider high-quality recycling of such materials.

Hazardous chemicals in post-consumer wastes

All chemicals that are integrated into products during production processes will become waste as part of the products after the end of their service life. Currently, there are hardly any mechanisms, how the companies of the waste treatment chain can get information on the composition of end-of-life articles that become waste. This lack of information on the content of hazardous chemicals in wastes can be problematic in several ways, in particular:

Workers in waste treatment companies do not know the hazards from the materials they handle;
The implementation of a circular economy hindered as waste collectors cannot separate wastes with hazardous substances from wastes that are free of them and is challenging for producers of secondary materials to determine the content of hazardous chemicals (or ensure they are absent).

Therefore, substituting hazardous chemicals in products is the best option to avoid problems in waste treatment and support the circular economy.