Industrial monitoring and control instruments: exemption for cadmium anodes in Hersch cells

Closed 10 May 2024

Opened 15 Mar 2024


The Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment Regulations 2012 (the RoHS regulations) restricts the use of 10 hazardous substances in electrical and electronic equipment (EEE), with a view to contributing to the protection of human health and the environment, including the sound recovery and disposal of waste.

Industry can apply for exemptions to allow the supply of products using one or more of the restricted substances above the threshold limits set down in the RoHS regulations where specified criteria are met. Applications for exemptions are made to the Secretary of State under regulation 6 of the Hazardous Substances and Packaging (Legislative Functions and Amendment) (EU Exit) Regulations 2020 (the 2020 regulations). Any exemption that is granted can be used across industry, not just by the business that applied for the exemption. Exemptions are granted where it is determined that the necessary criteria have been met following a detailed evaluation conducted in accordance with regulation 5 of the 2020 regulations.

Following the UK’s withdrawal from the EU, the function of granting, renewing and revoking exemptions were, in relation to Great Britain, transferred to the Secretary of State by the 2020 regulations, using powers in section 8 of the European Union (Withdrawal) Act 2018 (the Withdrawal Act).

Part of the evaluation process is an 8-week consultation to collect contributions from stakeholders.

A request for renewal for an exemption was submitted for cadmium anodes in Hersch cells for oxygen sensors used in industrial monitoring and control instruments, where sensitivity below 10ppm is required. These oxygen sensors are used in applications where maintaining the product integrity requires the prevention of oxygen permeation, therefore the measurement of extremely low levels of oxygen is necessary. Examples are pharmaceutical products, food packaging and solar panels that require a high oxygen barrier. The cadmium specified in the exemption request is used as the anode of the coulometric sensor.

The requested duration of the exemption is for 7 years (the maximum period under the 2020 Regulations) and according to the application it would be expected to lead to the introduction of 0.224 kg of cadmium to the UK market annually. The applicant states that elimination or substitution of cadmium whilst maintaining the current technical performance is scientifically or technically impracticable.

The exemption covers monitoring and control instruments in industry under category 9 (industrial) of electrical and electronic equipment (EEE), as covered in the 2012 RoHS regulations.

The applicant proposed the following change in the wording of the current exemption entry: Cadmium anodes in electrochemical Hersch cells for oxygen sensors for measurement of permeation.

The original wording is: Cadmium anodes in Hersch cells for oxygen sensors used in industrial monitoring and control instruments, where sensitivity below 10ppm is required.

Under Regulation 5, an exemption may only be granted where the following conditions are satisfied:

  1. The exemption does not weaken the environmental or health protection afforded by UK REACH; and 
  2. The elimination or substitution of the material or component, via design changes or use of materials or components which do not include any restricted substances, is scientifically or technically impracticable. 
  3. The reliability of substitute materials or components is not ensured; or 
  4. The total negative environmental, health and consumer safety impacts caused by substitution of another material or component is likely to outweigh the total environmental, health and consumer safety benefits of that substitution.  


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