The REACH regulation envisage that the placing on the market and use of substances fulfilling the criteria as very high concern are subject to  authorisation.

What is a substance of very high concern?

Acccording to article 57 of the Regulation, a substance is considered as "of very high concern", if it is a:
- carcinogenic 1A-1B
- and/or mutagenic 1A-1B (i.e. it is responsible for some mutations of genes)
- and/or toxic for reproduction 1A-1B
- and/or (very) persistent, (very) bioaccumulative (it accumulates in the body over time) and toxic (criteria defined in appendix XIII).
- or even substances for which there is scientific evidence  of probable serious effects to human health or the environment   which give rise to an equivalent level of concern to those other substances listed above (they are then analysed on a case by case basis).

When a substance is identified as being of very high concern, it will be included in the candidate list of substances for authorisation (candidate list). This substance may be given priority treatment and included in the list of substances that require authorisation (annex XIV) so that it can be subjected to authorisation.

Such substance can no longer be marketed or used after a given date, unless authorisation is granted for specific use of this substance.

For example, Belgium has proposed to classify the substance "2-Ethoxyethyl acetate" (specifically used in industrial processes) as a substance of very high concern based on its toxicity for reproduction (ref. art. 57c of the REACH regulations). The Committee of ECHA member states has acknowledged it as such by including it in the candidate list.

The industries  that use/produce substances of concern are required to fulfil some obligations.
And the consumers, have the right to demand information about the substances contained in the products that they purchase. Besides, information on those hazardous substances is available to everyone, from the producer to the consumer, since 14 September 2021.