An obligation for authorisation exists for "Substances of Very High Concern".

This applies to:

CMR materials class 1 + 2

Such materials become authorised, if the manufacturer can prove that the risks are "sufficiently controlled". If safer alternatives should exist, the enterprises must submit a substitution plan, so that these materials can be possibly replaced.
The endokrin effective substance are excluded from the regulation. An examination will be accomplished six year after REACH entry into force, in order to be able to include new scientific results into the European chemical law. The period for the substitution can be individually specified on an individual case basis for each substance.

PBT/vPvB materials

These materials must be replaced by safer substances if possible.