GHS Classification Guidance for the Japanese Government

The classification is based on any of the following.
a) Positive result(s) from in vivo heritable germ cell mutagenicity tests in mammals; or
b) Positive result(s) from in vivo somatic germ cell mutagenicity tests in mammals, in
combination with some evidence that the substance has potential to cause mutations to
germ cells. This supporting evidence may, for example, be derived from
mutagenicity/genotoxic tests in germ cells in vivo, or by demonstrating the ability of the
substance or its metabolite(s) to interact with the genetic material of germ cells; or
c) Positive results from tests showing mutagenic effects in the germ cells of humans, without
demonstration of transmission to progeny; for example, an increase in the frequency of
aneuploidy in sperm cells of exposed human subjects.
Category 2:Chemicals which cause concern for humans owing to the possibility that they may
induce heritable mutations in the germ cells of humans.
The classification is based on any of the following.
a) Somatic cell mutagenicity tests in vivo, in mammals; or
b) Other in vivo somatic cell genotoxicity tests which are supported by positive results from in
vitro mutagenicity assays.
Note: Chemicals which are positive in in vitro mammalian mutagenicity assays, and which also
show chemical structure-activity relationship to known Germ Cell mutagens, should be
considered for classification as Category 2 mutagens.
B) Classification criteria in GHS (Reference information)
In classification criteria of JIS Classification and those of GHS, the same categories are
adopted.
(3)Items on information sources and data
*Regarding procedure of classification, refer to “3-1-1Sources of information
available for classification”
A)Data availability
1) In the UN GHS second revised edition, “mutagenicity tests” and “genotoxicity tests” have
different meanings. The mutagenicity tests are tests indexed with gene mutation, structural
and numerical abnormality of chromosome, and the genotoxicity tests are tests indexed
with other elements, for example, DNA damage and DNA repairing. There exist extremely
many kinds of mutagenicity tests and genotoxicity tests, and GHS shows examples of test
methods that provide criteria for classification as heritable mutagens (Note) in humans. In
table 3-8, in addition to GHS examples, several test methods are included to provide data
that serve as the basis for classification.
(Note) The purport of GHS Categories is to take account of heritable mutagenicity effects in
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