UK REACH – DOTL RMOA - Call for evidence

Closed 10 Apr 2022

Opened 9 Feb 2022


The UK REACH work programme for 2021/22 states that we will assess all the substances that have been submitted for identification as Substances of Very High Concern (SVHCs) in EU REACH at the time the work programme was published (if they are not already on the UK REACH Candidate List) and consider if they are appropriate for SVHC identification in UK REACH. As a result of an initial assessment  of these substances, HSE and the Environment Agency identified 4 substances requiring a regulatory management options analysis (RMOA).

Following on from this work, the UK, Welsh and Scottish Governments have asked HSE and the Environment Agency to prepare a RMOA for dioctyltin dilaurate, stannane, dioctyl-, bis(coco acyloxy) derivatives, and any other stannane, dioctyl-, bis(fatty acyloxy) derivatives wherein C12 is the predominant carbon number of the fatty acyloxy moiety. For convenience we will refer to the group with the acronym DOTL. This RMOA will investigate the risks posed by DOTL and recommend the best approach to protect human health and the environment from any identified risks.

This call for evidence aims to gather information and evidence that will support HSE and the Environment Agency with the preparation of the RMOA. We are interested in all aspects of the manufacture, import, hazard profile, use and exposure, environmental fate, waste and its disposal requirements, recycling opportunities for these substances and products that contain these substances, and any legislation and standards that apply, including product specific legislation and standards.

UK REACH came into force at the end of the EU exit transition period (31st December 2020) and regulates the access of chemicals to the GB market. Under the Northern Ireland Protocol, EU REACH continues to regulate the access of chemicals to the Northern Ireland market.

Please support your contribution with references and reliable data (facts and figures).

Background note

DOTL is a group of substances that was added to the EU Candidate List on 19th January 2021. The EU SVHC support document states that the group covered by the EU Candidate List entry is exemplified by the monoconstituent substance dioctyltin dilaurate (CAS 3648-18-8) and the UVCB substance stannane, dioctyl-, bis(coco acyloxy) derivatives (CAS 91648-39-4). UVCB substances are defined as substances of Unknown or Variable composition, Complex reaction products or Biological materials.

Substances covered by the EU Candidate List entry are typically manufactured using dioctyltin oxide and coconut fatty acids or commercial “lauric acid” as starting materials in the ratio 1:2. This results in substances comprised of constituents with variable alkyl chain lengths. The composition of coconut fatty acids has been described as including C6, C8, C10, C12, C14, C16, C18, C20 saturated and C18 unsaturated alkyl chains at various concentration levels.

One example of carbon chain length distribution given in the EU SVHC support document is (weight %):

  • Caproic acid, C6: 0-0.8
  • Caprylic acid, C8: 5.0-9.0
  • Capric acid, C10: 6.0-10.0
  • Lauric acid, C12: 44.0-52.0
  • Myristic, C14: 13.0-19.0
  • Palmitic acid, C16: 8.0-11.0
  • Stearic acid, C18: 1.0-3.0
  • Oleic acid, C18:1: 5.0-8.0
  • Linoleic acid, C18:2: 0.0-1.0
  • Arachidic acid, C20: 0.0-0.5

UVCB substances like this may be described by a name reflecting the source e.g. stannane, dioctyl-, bis(coco acyloxy) derivatives or a name reflecting the variability of the alkyl chain length such as, but not limited to, “Reaction product of dioctyltin oxide with fatty acids C12-16 even numbered”. Different people may use different alkyl descriptors (e.g., C10-16 even numbered, …) to represent the carbon number distribution in the substance name.

Since the hazardous properties correlate to the composition of these substances, the EU Candidate List entry applies to all dioctyltin dialkyl substances that are represented by an alkyl descriptor that may also be considered for coconut fatty acids.

DOTL is used predominantly as a catalyst in the manufacture of a variety of polyurethane applications, including rigid foams, varnish and powder coatings and sealants. DOTL based products also catalyse processes for manufacturing polyester polyols and other polyester products such as the cross-linked low-density polyethylene cable insulation that is used for communications applications and high voltage power cables which may be used underground, overhead, across the oceans, in buildings, tunnels, vehicles, ships, trains etc.

DOTLs and all substances, mixtures or articles that contain DOTL either intentionally or where it is present as an unintentional residue or by-product are within scope of this call for evidence.

If you are unsure if the substance you are providing information for falls within scope of the substance definition given in the EU Candidate List, please submit your information anyway.

HSE’s Confidentiality and GDPR statements

HSE tries to make its call for evidence procedure as thorough and open as possible.

Information provided in response to this call for evidence may be subject to publication or disclosure in accordance with the access to information regimes (these are primarily the Freedom of Information Act 2000 (FOIA), the General Data Protection Regulations (GDPR) and the Environmental Information Regulations 2004 (EIR)). Statutory Codes of Practice under the FOIA and EIR also deal with confidentiality obligations, among other things.

If you would like us to treat any of the information you provide as confidential, please make this clear in your response. If we receive a request under FOIA or EIR for the information you have provided, we will take full account of your explanation, but we cannot give an assurance that confidentiality can be maintained in all circumstances.

An automatic confidentiality disclaimer generated by your IT system will be disregarded for these purposes. Requests for confidentiality should be made explicit within the body of the response.

HSE will process all personal data in accordance with the GDPR. This means that personal data will not normally be disclosed to third parties and any such disclosures will only be made in accordance with the Regulations.

How to submit comments

Basic information can be provided in the call for evidence survey below. More detailed information should be provided in document(s) which can be submitted as attachments at the end of each section. We will not automatically publish information submitted in response to a call for evidence. However, it will be helpful if a “public version” of your information can be provided. We ask for this because we will share a draft version of the RMOA with interested stakeholders to allow them to comment on our proposed regulatory approach. By providing us with a non-confidential version of any information you submit, this will help us understand which information we can include in the public RMOA. If you also want to provide confidential information in your submission, please additionally complete a “confidential version” and submit both versions as attachments. We will take account of both non-confidential and confidential information when deciding which regulatory approach to propose.

When responding to this questionnaire, please answer all question sets that are relevant to you. For example, if you manufacture the substance and also import the substance, please answer questions for both manufacture and import. You do not need to duplicate information if you have provided this under a previous question set. In this case, please indicate where in the questionnaire the information has been given. If you do not have time to complete this questionnaire (or do not find any questions relevant) but are willing to contribute information for the RMOA, please use the comment box under the question “Do you have any other information that you think might help HSE and/or the Environment Agency with this RMOA?” to indicate what information you are willing to share and tick that you are willing to be contacted by HSE and EA.  This can be found in the section headed “Other questions” at the end of this call for evidence.

By submitting information as part of this call for evidence, you agree that any data provided (excluding your personal details) can be shared with the Environment Agency.

The call for evidence lasts for 60 days and closes at 23:59 London time (BST).


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