How to substitute and evaluate alternative?
Substitution means the reduction or replacement of hazardous substances in products and processes with less hazardous or non-hazardous substances, or through achieving an equivalent functionality via technological or organisational measures
What are the advantages of substitution?
What are the legal requirements?
Employers are required to assess hazardous substances used in the workplace and, where technically feasible, to substitute chemicals that are carcinogenic, mutagenic or reprotoxic.
Substitution is driven by broader regulatory frameworks:
- REACH authorisation (Annex XIV and candidate list) and restriction (Annex XVII) processes,
- Product-specific legislation (Decopaint Directive, Industrial Emissions Directive),
- Workplace legislation,
- International conventions such as the Stockholm Convention on Persistent Organic Pollutants.
Types of chemical substitution
Elimination of a chemical (no replacement)
Example: A fragrant ingredient in a mixture is removed as it has no function other than providing a pleasant smell during product use.
Drop-in substitution (1 to 1) of a chemical (one chemical is replaced by another without additional changes)
Example: Cadmium containing yellow pigment in a mixture is replaced by an organic yellow pigment which is not considered hazardous.
Changed product or process design by implementing chemical alternative
Example: In polymer pellets the phthalate plasticizer DEHP is replaced by the plasticizer DINCH. The entire polymer needs to be reformulated (by re-adjusting the concentrations of most other components) to achieve the desired function.
Changed product or process design by implementing non-chemical solution
Example: The product’s main material is changed from plastic to glass, e.g., in packaging. This would involve the use of very different chemicals, potentially eliminating the need to use plasticisers.
Changed product or process design by implementing new technology.
Example: Wood can be impregnated using biocides or by applying heat and pressure to the wood for a certain time.
Substitution process
Problem identification
Start by identifying substances of concern that are currently in use. Compile a comprehensive inventory of all substances you handle as the basis for this assessment.
Identify the key functions that your substance of concern performs in the product or process.
More on Inventory: What is a chemical inventory?
Prioritise substances for substitution by focusing on those that are the greatest cause for concern. These typically include highly hazardous substances, substances that are not essential for the product’s functioning, and those likely to face regulatory restrictions or increasing market pressure in the short term.
Defining the scope of substitution
Defining the scope of substitution involves the identification of criteria to evaluate alternatives.
These criteria may concern:
- the quality/performance of the product,
- “acceptable hazardousness” of the alternative,
- the scale of reformulation that is acceptable,
- possible costs,
- the use of different equipment,
- customer requirements, etc.
These criteria are a good basis for later decision making and help to maintain focus on the essential aspects of substitution.
Inform and consult your supply chain, both clients and suppliers, to identify potential concerns and options.
Searching for alternatives
Start by defining the quality and performance of the product and identify all possible options that could lead to the elimination of the chemical of concern. These options may also include technical options, e.g., if a processing aid should be phased out, or using different materials (e.g., discuss with the customer whether or not to change from one type of polymer to another).
Various sources and contacts can help you to find alternatives:
- inside your company, the purchasing department, the sales department or the technical officers may have good advice about products or suppliers to contact,
- suppliers, especially if they offer alternatives. However, please note that, while not yet being regulated or being considered by product designers, the alternatives may belong to a similar or the same (chemical) group and may pose the same or similar hazards, i.e. they would be regrettable substitutes,
- research alternative chemicals online using search engines, screening scientific literature, contacting industry associations, governmental authorities, universities, or other experts who may consult on safer chemicals and product design,
- It may also be possible to team up with customers or even competitors to find shared and good solutions.
Assessing, comparing and selecting alternatives
Preliminary
All alternatives should be compliant with the regulatory requirements of your target markets and should not be banned or restricted in any legislation.
A practical approach is to first do a quick screening of all options – preliminary assessment, remove options that are clearly unsuitable, and then assess the remaining ones in more detail.
Assessing, comparing and selecting alternative
Further assessment should cover:
- hazard and risk assessment,
- assessment of technical feasibility,
- assessment of economic viability,
- additional environmental impacts may be assessed.
In addition, communicate with your customer to ensure the reformulated product meets its requirements.
| Assessment area | Necessity of inclusion in the alternatives assessment |
| Hazard assessment | Always include it |
| Technical assessment | |
| Economic assessment | |
| Exposure assessment | Include if alternatives have similar hazardous properties in order to differentiate which of them is more likely to cause risks to humans or the environment |
| Environmental assessment | Include depending on the case, e.g. to support decision making on two similarly hazardous/risky alternatives or if the reduction of environmental impacts is very important to your company policy |
| Social assessment | Include if you find it relevant |
Preliminary assessment
Preliminary assessment focuses on screening substances based on their hazardous properties. At this stage, alternatives associated with the most severe hazard classifications are identified so that they can be screened out early in the process.
Preliminary assessment: screening out to ascertain whether substances are included in regulatory lists:
- The REACH candidate list of substances of very high concern (SVHCs). Although the candidate list does not directly ban the listed substances, it is a recognition of serious human and/ or environmental concerns. Substances from the candidate list may become subject to REACH authorisation (Annex XIV) in the future,
- The REACH restrictions (Annex XVII) screen out if a restriction directly applies to your product usage or the intended use of your mixture by customers. If restrictions exist for uses other than yours or that of your customers, it is not an immediate reason to screen out the substance. However, it is an indication of potential future regulation, and you should note this in your further assessment,
- the list of POPs according to the EU POPs regulation.
Alternatives should also be screened out, if they have any of the following hazardous properties but are not (yet) listed on a regulatory list:
persistent, bioaccumulative and toxic (PBT), very persistent, very bioaccumulative (vPvB), persistent, mobile and toxic (PMT), very persistent, very mobile (vPvM),
carcinogenic, mutagenic, reprotoxic (CMR), category 1, preferably also category 2,
endocrine disrupting chemicals (EDC) categories 1 and 2.
Check the SIN list as it includes a lot of substances with the aforementioned properties. It is not a regulatory list but includes two types of substances:
a) Substances listed on the REACH candidate list and/or that are regulated under the REACH restriction and/or authorisation process.
b) Substances that have been evaluated by scientists as possessing SVHC properties, but which have not been officially identified (yet), e.g., via SVHC identification or classification; i.e. no process of verifying the properties by authorities has yet taken place.
Substitution is very important
| Property | Hazard statement | |
| Code | Text | |
| PBT and vPvB * | EUH440 | Accumulates in the environment and living organisms including in humans |
| EUH441 | Strongly accumulates in the environment and living organisms including in humans | |
| PMT and vPvM* | EUH450 | Can cause long-lasting and diffuse contamination of water resources |
| EUH451 | Can cause very long-lasting and diffuse contamination of water resources | |
| CMR | H350 | May cause cancer |
| H340 | May cause genetic defects | |
| H360 | May damage fertility or an unborn child | |
| H361 | Suspected of damaging fertility or an unborn child | |
| Endocrine disruption | EUH380 | May cause endocrine disruption in humans |
| EUH381 | Suspected of causing endocrine disruption in humans | |
| EUH430 | May cause endocrine disruption in the environment | |
| EUH431 | Suspected of causing endocrine disruption in the environment | |
* As the hazard statements of these properties came into force in 2025, there are not yet many classified substances.
Second priority
| Property | Hazard statement | |
| Code | Text | |
| Acute toxicity | H310 | Fatal if coming into contact with skin |
| H330 | Fatal if inhaled | |
| Reproductive toxicity | H362 | May cause harm to breast-fed children |
| Specific target organ toxicity | H372 | Causes damage to organs through prolonged or repeated exposure |
| Long-term (chronic) aquatic toxicity | H410 | Very toxic to aquatic life with long-lasting effects |
Substitution should be considered
| Property | Hazard statement | |
| Code | Text | |
| CMR | H351 | Suspected of causing cancer |
| H341 | Suspected of causing genetic defects | |
| Acute toxicity | H331 | Toxic if inhaled |
| Sensitisation | H317 | May cause an allergic skin reaction |
| H334 | May cause allergy or asthma symptoms or breathing difficulties if inhaled | |
| Specific target organ toxicity | H371 | May cause damage to organs |
| H373 | May cause damage to organs through prolonged or repeated exposure | |
| Long-term (chronic) aquatic toxicity | H411 | Toxic to aquatic life with long-lasting effects |
Hazard assessment
1) Compare and benchmark hazards based on the EU classification as a first step. The more severe the hazards are, the less suitable the alternative is from an (eco) toxicological point of view.
In the event that no classification is available, you may find test results for at least some endpoints in the ECHA’s database or other scientific sources that you may use to compare hazards. You may want to compile a ranking list according to hazards.
Ensure that you are aware of the availability of information and what you do not know (and that could turn out to be a bad surprise in the future).
2) After alternatives with unacceptable hazards have been screened out, a comparison of the hazards of the remaining alternatives should follow. The hazard assessment needs to be conducted for the recipe of the mixture after the substitution.
As substituting one chemical normally involves changing large parts of the mixture composition, the concentration of several ingredients may change, and more than one new substance may be included in the mixture. In order to assess the change in hazard, all changes in components and their concentration (if above 25% of the original concentration) compared to the original composition should be included in the hazard assessment.
As the exact composition will only be determined during technical testing of an alternative, you should work with an assumed composition at this stage.
The online tool ChemSelect supports the sustainability assessment of substances and mixtures, including a comparison of mixtures regarding their hazardousness. The GHS Column Model can assist you in the comparison of hazards: it provides a system or hierarchy of hazards clearly indicating what is “better or worse”.
It is not always possible to find non-hazardous or non-classified substitutes to replace hazardous substances. Certain hazards may be acceptable if the chemical replaces a more hazardous one; i.e., improvements may be better than not acting at all.
Exposure assessment
The assessment of exposures indicates the likelihood and extent to which humans, workers, consumers and the environment could be exposed to the chemical during its entire life cycle.
When it comes to the exposure assessment, you should only consider mixture components that have changed or whose concentration has changed by over 25%.
- If the mixture becomes a material, e.g., polymer, metal or glass, the release of substances during processing, service life and/or the waste stage is largely determined by the type of chemical bounds of substances to the matrix (i.e. metallic, covalent, ionic, etc.) rather than mobility properties,
- If the alternative you select is a drop-in solution, i.e. you replace one chemical with another chemical with only minor changes to the overall mixture, the conditions of use and emission situation from the mixture are probably going to be the same for the original mixture and the alternative one. In this case, you can just compare the mobility parameters – volatility, water solubility – of the substances to identify whether a significant change in risk would occur. In most cases, the change in hazard will be the dominating factor,
- If the alternative results in a larger change of the mixture composition, the assessment of whether the substitution is useful or not is more complex, because all the substances that are changed (or the concentration of which are changed) need to be considered, along with any changing conditions of use both at the formulation stage and further down the life cycle of the substance.
The first step in this process is to check whether hazardous substances can be emitted from the mixture and to what extent. The answers are determined by production processes and the use of the mixture, as well as the physical-chemical properties of the relevant substances in the mixture.
Technical assessment
The technical feasibility of an alternative is one of the critical factors in the assessment. If, after substitution, a mixture fails to meet the technical requirements, it is not a viable option.
As it is not always possible to anticipate technical feasibility, laboratory tests with alternative mixtures may have to be conducted, in particular to identify the performance for downstream users.
At this stage, an assumed composition may be used for the assessment, because the exact one will only be determined during technical testing and product development.
Laboratory-scale testing provides an initial assessment of suitability. Subsequently, promising candidates are evaluated through testing at technical scale. The technical assessment should also include the step of obtaining feedback from customers.
A detailed analysis should encompass performance, health and safety aspects, and operational feasibility. The analysis should answer the following questions:
- Will switching to a new chemical/new mixture composition necessitate major changes to your own equipment and processes? If so, is a change in process or equipment feasible?
- Will the product’s quality continue to meet customer expectations; i.e. will the quality of the final product containing the mixture, or for the purposes of which it is used, remain the same or improve or deteriorate?
- Will customers have to make any changes in the equipment and production processes in which the mixture is used and is this feasible? Have you discussed this with the customers concerned?
- Are there specific health and safety standards the chemical must comply with for workplace safety?
Economic assessment
The economic assessment may include analysis of:
- Investment costs (e.g., for new machinery),
- Prices of alternative(s),
- Potential savings from reduced waste or the elimination of previously required personal protective equipment,
- Market changes resulting from the redesigned product, including opportunities to obtain eco-labels,
- Training costs,
- Options for adjusting mixture prices to recover investments.
Several factors need to be considered, many of which can only be estimated rather than calculated precisely.
The analysis should address the following questions:
- Are the substitute substances sufficiently and reliably available (e.g., by ascertaining the number of suppliers, supply security, and whether the product is new or well established)?
- What are the costs of introducing and using the alternative, including investment, research and development for reformulation, re-labelling, and related activities?
- How close must the alternative’s price be to the current one to remain competitive?
- Consider life cycle costs rather than comparing prices alone.
- What benefits result from adopting the alternative, e.g., reduced risk management costs (waste handling, worker protection, etc.), improved legal compliance, and access to new or expanded markets?
Testing alternatives in real production
The last step of testing involves the use of the alternative at scale during normal production. Any challenges related to processing in the installation or product quality that could not be observed in lab-scale reformulation will emerge during full-scale production processes. Customers should be involved in this technical testing to ensure that the subsequent processing is not affected by the change in mixture composition.
Testing may require the specific attention of technical staff, as the manufacturing parameters have to be changed due to the (partly different) properties of the alternative(s). Be sure to keep good documentation and record keeping of your testing so that details on the tests are available at later stages in the process.
Apply the quality criteria defined in the first step to evaluate whether an alternative fulfils all the relevant requirements. You may want to conduct chemical analyses to ensure that the mixture does not contain any unwanted impurities or reaction products.
After completing the aforementioned steps, you should be able to make a sound and justified decision regarding which alternative to choose.
Implementation and checking of success
The last step in the substitution process is the use of the selected alternative in your full-scale manufacturing process. In all probability, you will be able to improve manufacturing efficiency over time as you work with the new material.
When introducing the new or changed product to your customers, be ready to take (critical) feedback and further improve or change the composition of the mixture.
More resources
Simple Alternatives Assessment Kit for Formulators
The simple alternative assessment kit highlights key points for formulators to consider and provides some guidance on situations in which an alternative can be considered to be “better” based on screening information. The kit outlines the assessment process, introduces several tools for assessment, and provides links to other frameworks and tools.
ChemSelect tool, available in several languages.
ChemSelect is an online application that supports the sustainability assessment of substances and mixtures. Based on nine criteria, you can create a sustainability profile or compare different substances and mixtures with one another. It is designed for small and medium-sized enterprises that use chemicals in their processes and products. ChemSelect can be used with basic knowledge on chemicals (i.e. you should know safety data sheets and understand the main content)
USEtox is a scientific consensus model endorsed by UNEP’s Life Cycle Initiative for characterising human and ecotoxicological impacts of chemicals. The main output is a database of characterisation factors including fate, exposure, and effect parameters.
Substitution and Alternatives Assessment Toolbox (SAAToolbox)
The OECD Substitution and Alternatives Assessment Toolbox (SAAToolbox) compiles resources relevant to chemical selection including substitution and assessment of alternatives, as well as the OECD SSIA (Safe(r) and Sustainable Innovation Approach) for nano-enabled and other emerging materials.