There are three types of IFRA Standards:
Prohibited means that an IFRA Standard may ban the use of a substance when it is intended to be used as such in a fragrance compound.
However, this does not necessarily exclude the use of a fragrance material (natural or synthetic) which contains the same substance as a component or contaminant provided, in the judgment of the Expert Panel on Fragrance Safety, there are sufficient data supporting the safe use of the fragrance material, and that it is not being used to provide an alternative, indirect source of the banned substance.
Restricted means that you can use this material but only below a certain concentration in the finished product.
Specification means that you have to respect a purity criteria.