The new CLP classification of silver has changed the regulatory assessment of elemental silver in the European Union since May 1, 2026. For the electronics manufacturing industry, this raises an important question: what does the new classification mean for SAC305, solder pastes, solder bars, pellets, and other silver-containing solder alloys?
Silver has been one of the most important alloying elements in electronics manufacturing for decades. In particular, the lead-free alloy SAC305 – Sn96.5Ag3.0Cu0.5 – is widely established in many soldering processes.
With Delegated Regulation (EU) 2024/2564, the 22nd Adaptation to Technical Progress (22nd ATP) of the CLP Regulation, elemental silver has received a new harmonised classification.
What Has Changed for Silver?
The new regulation concerns elemental silver, CAS No. 7440-22-4. It distinguishes between different forms of silver depending on particle size:
- massive silver with a particle diameter of at least 1 mm,
- silver powder with a particle diameter greater than 100 nm and less than 1 mm,
- silver nanoparticles with a particle diameter greater than 1 nm and up to 100 nm.
All three forms are classified as Reproductive Toxicity Category 2 (Repr. 2) with:
H361f – Suspected of damaging fertility.
In addition, silver is classified as STOT RE 2 with H373 due to potential effects on the nervous system following prolonged or repeated exposure.
Silver powder and silver nanoparticles are additionally subject to classifications relating to hazards to the aquatic environment.
Why Is This Relevant to the Electronics Industry?
Silver is a constituent of many solder alloys. One of the best-known examples is SAC305:
Sn96.5Ag3.0Cu0.5
This alloy contains 3.0% silver by weight.
This concentration is particularly relevant from a regulatory perspective. Under the general CLP rules, a component classified as Repr. 2 can, in principle, lead to the classification of a mixture as Reproductive Toxicity Category 2 at a concentration of 3.0% or above, unless specific concentration limits or other rules relevant to the particular product form apply.
The standard composition of SAC305 therefore sits directly at a regulatory concentration threshold that requires careful consideration.
SAC305 Is Not Always the Same as SAC305
When assessing the impact of the new classification, it is important not to consider chemical composition alone.
The harmonised classification of silver explicitly distinguishes between massive silver, powder, and nanoparticles. The physical form of the material therefore also plays a role in the regulatory assessment of a solder product.
This is particularly relevant when comparing different product forms.
Solder Bars
In solder bars, the metal is present as a massive product. The harmonised classification for massive silver includes Repr. 2, H361f and STOT RE 2, H373.
Pellets, Preforms and Other Metal Forms
For pellets, preforms, and similar products, dimensions and physical form must also be considered. The product name alone does not determine the applicable classification.
Solder Paste
The situation is different for solder paste. Here, the alloy is present as fine solder powder dispersed in a flux medium.
The regulatory assessment must therefore consider not only the silver content of the alloy itself, but also the actual silver concentration in the complete solder paste and the classifications of its other components.
A SAC305 solder paste does not consist of 100% SAC305 metal powder.
Does the New Classification Mean SAC305 Can No Longer Be Used?
No.
A CLP classification is first and foremost a hazard classification. It does not automatically constitute a ban on the substance or alloy.
However, the new classification requires affected products to be reviewed. Manufacturers, importers, and downstream users should verify whether existing classifications, Safety Data Sheets (SDS), labels, and workplace risk assessments remain correct.
For users, this does not mean that established SAC305 processes automatically need to be changed.
It does mean that the regulatory assessment of the products being used should be up to date.
What Should Electronics Manufacturers Check?
Companies using silver-containing solder products should review several areas.
1. Current Safety Data Sheets
Check whether up-to-date Safety Data Sheets are available for solder pastes, solder bars, wires, pellets, and preforms, and whether the new silver classification has been taken into account.
2. Silver Content
Not every silver-containing alloy is the same. SAC305, for example, contains 3.0% Ag, while other solder alloys may contain significantly lower or higher concentrations.
3. Product Form
Solder paste, solder bars, and other metal products should not automatically be treated in the same way from a regulatory perspective. The physical form of the silver is relevant to the classification.
4. Labelling
If the CLP classification of a product changes, this may affect hazard pictograms, signal words, and hazard statements.
5. Workplace Risk Assessments
Where a product receives a revised classification, existing workplace risk assessments and operating instructions should be reviewed and updated where necessary.
6. Alternative Alloys
The regulatory change can also provide an additional reason to review an existing alloy strategy. However, regulatory considerations should not be evaluated in isolation.
Are Low-Silver Alloys Automatically the Better Solution?
Not necessarily.
Silver content affects not only cost and regulatory considerations but also the technical properties of a solder alloy.
When considering a change of alloy, manufacturers should evaluate factors such as:
- melting range and reflow profile,
- wetting behaviour,
- mechanical properties,
- thermal reliability,
- voiding,
- component and surface-finish compatibility,
- existing customer approvals and qualifications.
Changing an alloy should therefore always be evaluated from both a technical and process perspective.
The question should not simply be:
“How can we avoid silver?”
A more useful question is:
“Which alloy provides the best balance of process stability, reliability, cost, and regulatory requirements for our specific application?”
Silver Is Becoming a Strategic Issue
The discussion around silver in electronics manufacturing is changing.
Until recently, much of the focus was on the price development of silver and its impact on solder alloy costs. The new CLP classification adds another dimension: regulatory compliance.
As a result, alloy selection increasingly needs to consider several factors simultaneously:
Performance – Process – Cost – Availability – Sustainability – Regulation
For well-established alloys such as SAC305, this does not mean that existing processes should be changed prematurely. However, it does mean that alloy strategies should be reviewed regularly as technical, economic, and regulatory conditions evolve.
Conclusion
Delegated Regulation (EU) 2024/2564 has significantly changed the regulatory assessment of elemental silver in the European Union. The new harmonised classification has been mandatory since May 1, 2026.
This is particularly relevant to electronics manufacturing because silver is an important constituent of many established solder alloys.
SAC305 remains an important and widely used lead-free solder alloy. The new classification does not automatically mean that SAC305 needs to be replaced. However, silver-containing products should be carefully reviewed with regard to their classification, Safety Data Sheets, labelling, and use in the workplace.
At the same time, the regulatory change provides a good opportunity to reassess existing alloy strategies and determine whether SAC305 or an alternative alloy represents the best long-term solution for a particular application.
Do you have questions about selecting the right solder alloy or would you like to review an existing application? Contact us. Solder Chemistry can support you in selecting a technically suitable solution for your soldering process.
Note: This article is intended to provide general technical information and does not constitute legal or regulatory advice.
