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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Classification & Labelling & PBT assessment

PBT assessment

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Administrative data

PBT assessment: overall result

PBT status:
the substance is not PBT / vPvB

Comparison with the Criteria of Annex XIII An assessment of the PBT status of MTBE has been made using all available data.

Persistence Assessment

A closed bottle test (OECD 301D; see Section showed that MTBE is not readily biodegradable; MTBE is therefore identified as being potentially persistent.

Bioaccumulation Assessment

Whole-body bioconcentration factors (BCF) of 1.5 and 1.4 were reported for Japanese carp (Cyprinus carpio) exposed for 28 days (see Section 4.3.1). MTBE is therefore not bioaccumulative.

Toxicity Assessment

The acute effect concentrations for all three trophic levels are much higher than the PBT screening criterion of 0.1 mg/l. It can therefore be expected that MTBE is not potentially toxic towards aquatic organisms. The chronic effect concentrations for invertebrates, algae and fish were higher than the definite PBT criterion of 0.01 mg/l. In addition, MTBE is not classified as being CMR and there is no evidence that MTBE is chronically toxic towards mammals. Therefore, based on the aquatic and mammalian toxicity data, MTBE is not assigned as being toxic.


The overall conclusions, based on the present available data, are that the (screening) criteria for PBT/vPvB, as outlined in Annex XIII of Directive 2006/121/EC, are not met and that further testing in the scope of the final PBT assessment is not considered to be required.

Likely routes of exposure:

Emission Characterisation MTBE is not a PBT/vPvB substance, therefore an emission characterisation does need not to be conducted.