GHS Classification Guidance for the Japanese Government

and scaling persist to the end of 14 days after application in at least 2 of 3 tested animal,
or
c) Definite positive effects are recognized in an animal, but its extent does not satisfy
criteria 1) and 2) above. (e.g. when a pronounced variability of response is found among
animals, with a definite lesion recognized at the end of the observation period in only 1
of 3 tested animals).
2) Decision by comparison with existing classification:
The substance classified as Severe or Corrosive is determined as Corrosive (Category 1),
and the substance classified as Severe with no irreversible lesion observed is determined
as Irritant (Category 2).
The substance classified as Moderate is determined as Irritation (Category 2).
It is preferable to confirm PII (skin primary irritation index) and the like as far as
possible, and to classify the substance in question as moderate (corresponding to PII3-5)
or severe (corresponding to PII 6-8). Also, it is preferable to determine the
corresponding category at least upon confirming which classification criteria the given
existing classification is based on since substances classified as “moderate” based on
different classification criteria may cause different degrees of skin reaction.
3) Decision by symptom(when no other information is available):
When described as necrosis, the substance is determined as corrosive (Category 1).
D) Decision by structure-activity relationship or structure-property relationship
In classification, this shall not be considered at all. However, if there is a description that
the substance is judged to be classed in a given class by the analysis of the structure-activity
relationship in the assessment document of List 1, the substance is classified based on the
result.
E) Decision by physicochemical properties
In the case of pH≤2 and pH≥11.5, the substance is classified as Corrosive (Category 1)
(Determination is performed with buffering capacity also taken into account.) (Booman et al
(1989) proposed 0.2 meq HCl/g for eye irritation.)
A paper is given below that shows examples that irritation is not determined by pH alone
but affected by composition of acids or alkalis.
“Classification as Corrosive or irritant to Skin of Preparations Containing Acidic or
Alkaline Substances、 without Testing on Animals”, YOUNG.J,et. al (SDA)、Toxicol in
vitro VOL.2 NO.1 PAGE 19-26 (1988)
F) Decision by In vitro test methods
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