REACH - Applications for authorisation AFA039-01 Multiple Cr(VI)

Closed 10 Jul 2023

Opened 15 May 2023


Public consultation on alternatives

Reference: AFA039-01


Wesco Aircraft EMEA Ltd (CT)
Boeing Distribution (UK) Inc (CT,SC)
MacDermid Performance Solutions UK Ltd (CT)
Henkel Ltd (CT)

Application Type: Initial

Substance Name:

Chromium Trioxide (includes “acids generated from chromium trioxide and their oligomers", when used in aqueous solutions) (CT)  

  • EC No: 215-607-8             
  • CAS No: 1333-82-0          

Sodium Chromate (SC)

  • EC No: 231-889-5             
  • CAS No: 7775-11-3          

Proposed Use: Anodise sealing using chromium trioxide and/or sodium chromate in aerospace and defence industry and its supply chains.

Broad Information on Use Applied for (Conditions of Use and Function): 

Anodise sealing using chromium trioxide and/or sodium chromate in the aerospace and defence supply chains is carried out exclusively in industrial settings. The anodise sealing processes provide corrosion resistance and active corrosion inhibition. It plays a critical (and currently irreplaceable) role in protecting aluminium and other alloys.

Anodise sealing is the final step in the anodising process. After anodising, the surfaces of substrates are naturally porous which impacts its corrosion resistance – anodise sealing closes the micropores to improve the resistance of the anodised surface. The process of anodise sealing is carried out by immersing anodised components in treatment baths.

The applicants have identified a shortlist of potentially suitable alternatives. Due to the complexity of design challenges, performance requirements, safety requirements and regulatory controls that must be tested for each listed alternative, and the need for industrial implementation in the whole supply chain, the applicant is seeking a review period of 12 years.

This “applied for use” involves the use of chromium trioxide and/or sodium chromate across approximately 35 sites across Great Britain (GB – England, Scotland, Wales).

List of Descriptors:  

  • Sector of end use (SU): 0 – Other: Aerospace and defence industry and its supply chains.
  • Environmental release category (ERC): 5.
  • Process Category (PROC): 0, 5, 8b, 9, 13, 15, 21, 24, 28.
  • Product category (PC): 14.
  • Article category related to subsequent service life (AC): N/A.
  • Technical Function: Other: corrosion resistance, active corrosion inhibition.

Annual Tonnage Used: 

  • Chromium trioxide < 0.5 tonnes/year
  • Sodium chromate < 0.5 tonnes/year

Review Period Requested: 12 years  

How to submit comments

Provide some basic information on possible alternative(s) in the online survey below but more detailed information should be provided in document(s) prepared using the commenting templates in the related section below. A “public version” should always be completed and will be published after the consultation has closed. If you want to include confidential information in your submission, please additionally complete a “confidential version” and submit both versions as attachments.

The consultation lasts for 8 weeks (unless otherwise specified) and closes at 23:59 London time (BST).


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  • Registration, Evaluation, Authorisation & restriction of CHemicals (REACH)