GHS Classification Guidance for the Japanese Government

(Notes)
a) Category 3 (transient target organ effects) is defined as “effects which adversely alter
human function for a short duration after exposure and from which humans may recover
in a reasonable period without leaving significant alteration of structure or function”.
Presently in GHS, classification criteria for Category 3 are shown regarding respiratory
tract irritation and narcotic effects. When descriptions suggesting narcotic effects based
on inhibition of nerve system function and action are found in the original literatures,
the substance in question is to be classified in Category 3. If there is any reversible
effect other than these effects, such effect shall be indicated in the special remarks in the
present classification work but shall not be the basis of classification.
b) As for respiratory tract irritation, when a more serious organ effect, including one on
respiratory system, is observed, the substance is classified in Category 1 or Category 2.
As for narcotic effects, only if the effect is not essentially transient, the substance
producing the effect is classified as Category 1 or Category 2.
c) When a substance is either a respiratory tract irritant or a narcotic, indicate it clearly.
(Example entry:Category 3 (respiratory tract irritation))
C) On treatment of vapour inhalation guidance value in classification of specific target organ
toxicity (single exposure)
As for the classification of specific target organ toxicity (single exposure), “guidance
values” for categorization based on animal data are shown in the p.170 Table 3-14 (UN GHS
second revised edition Table 3.8.1). All of them are indicated in the unit of mg/L for vapour
inhalation. However, there are no notes regarding vapour inhalation like those for acute
toxicity in Table 3.1.1. Therefore, regarding specific target organ toxicity (single exposure),
the toxicity manifestation concentration in mg/l at vapour inhalation should be examined and
evaluated by comparing it with the value shown in the Table 3.8.1. If the original data is
given in ppmV, the data should be converted into mg/L and compared.
If the concentration is at saturated vapour pressure or more, the value is treated as that of
mist (or dust) by referring to the case of acute toxicity.
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