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European Union - Final Regulatory Action
5-tert-Butyl-2,4,6-trinitro-m-xylene (Musk xylene) CAS number:
Date circular:

Chemical name: Benzene, 1-(1,1-dimethylethyl)-3,5-dimethyl-2,4,6-trinitro-

Final regulatory action has been taken for the category: Industrial

Final regulatory action: The chemical is Severely Restricted

Use or uses prohibited by the final regulatory action:

Industrial chemical.

Use or uses that remain allowed:

Pursuant to Regulation (EC) No 1907/2006 (REACH Regulation), only certain uses are exempted from the authorisation requirement, e.g. uses as intermediates or for scientific research and development activities, as described in the document Generic exemptions from the authorisation requirement []. From the exemptions specific to certain intrinsic properties mentioned in Section 2 of the linked document only the one referring to Article 57 (e) applies for musk xylene (see Section below for intrinsic properties of the substance).

The final regulatory action was based on a risk or hazard evaluation: Yes

Summary of the final regulatory action:

By Commission Regulation (EU) No 143/2011 of 17 February 2011 amending Annex XIV to Regulation (EC) No 1907/2006, 5-tert-butyl-2,4,6-trinitro-m-xylene (musk xylene) was included into Annex XIV (Authorisation List) of Regulation (EC) No 1907/2006 (REACH Regulation), which contains substances of very high concern that are subject to authorisation.
The listing of musk xylene in the Authorisation List has the effect that any use of this substance after 21.08.2014 (the Sunset Date) is prohibited (except for exempted uses as described in Section 2.3.2 of this document), unless a company submits an application for authorisation and the authorisation is granted. Since no applications for authorisation have been submitted to date only the exempted uses remain allowed. Hence, the final regulatory action severely restricts the use of musk xylene.

The reasons for the final regulatory action were relevant to: Environment

Summary of known hazards and risks to the environment:

Musk xylene was identified as a substance of very high concern (SVHC) meeting the criteria of a very persistent and very bioaccumulative (vPvB) substance pursuant to Article 57 (e) of Regulation (EC) No 1907/2006 (REACH Regulation).
The extractable part of musk xylene in sediment is subject to anaerobic degradation with half-lives of equal to or below 60 days. Musk xylene is therefore considered to be not persistent in sediment. In the assessment the observed irreversible binding to sediment is considered as dissipation.
Given the fact that the metabolites in the ocean die-away test stayed in the water phase while the parent compound musk xylene volatilized and the fact that the ratio metabolites: parent compound was still close to one after 159 days, it is concluded that the half-life for biodegradation in seawater is more than 150 days, which significantly exceeds the criterion of 60 days. Musk xylene is therefore considered to be very persistent in water.
Because sea and ocean water are compartments with a significant hold-up of the total amount of musk xylene, musk xylene should be regarded as fulfilling both the P and vP criterion.
The experimental bioaccumulation studies for musk xylene in fish showed a wide range of BCFs, among which values above the vB criterion of 5,000 l/kg. Based on the detailed re-evaluation of the critical study and on an additional study, it can be concluded that musk xylene is very bioaccumulative (vB).

Expected effect of the final regulatory action in relation to the environment:

Avoidance of risk for the environment from the use of musk xylene.

Date of entry into force of the final regulatory action: 21/08/2014