GHS Classification Result （Revision of the past classification result）

Chemical Name：Hydroquinone
CAS：123-31-9

Result：
ID: 176
Classifier: Ministry of Economy, Trade and Industry （METI）
Year Classified: FY2007
Reference Manual: GHS Classification Manual （10 Feb, 2006）

PHYSICAL HAZARDS
Hazard class Classification Symbol Signal word Hazard statement Precautionary statement Rationale for the classification
1 Explosives - - - - - -
2 Flammable gases （including chemically unstable gases） - - - - - -
3 Aerosols - - - - - -
4 Oxidizing gases - - - - - -
5 Gases under pressure - - - - - -
6 Flammable liquids - - - - - -
7 Flammable solids - - - - - -
8 Self-reactive substances and mixtures - - - - - -
9 Pyrophoric liquids - - - - - -
10 Pyrophoric solids - - - - - -
11 Self-heating substances and mixtures - - - - - -
12 Substances and mixtures which, in contact with water, emit flammable gases - - - - - -
13 Oxidizing liquids - - - - - -
14 Oxidizing solids - - - - - -
15 Organic peroxides - - - - - -
16 Corrosive to metals - - - - - -

HEALTH HAZARDS
Hazard class Classification Symbol Signal word Hazard statement Precautionary statement Rationale for the classification
1 Acute toxicity （Oral） - - - - - -
1 Acute toxicity （Dermal） - - - - - -
1 Acute toxicity （Inhalation: Gases） - - - - - -
1 Acute toxicity （Inhalation: Vapours） - - - - - -
1 Acute toxicity （Inhalation: Dusts and mists） - - - - - -
2 Skin corrosion/irritation Category 3 - Warning H316: Causes mild skin irritation P332+P313: If skin irritation occurs: Get medical advice/attention. Although there are two test examples having indicated moderate or more irritation by application with high concentration over time, other four examples show mild or less irritation. Therefore, since it is believed that the substance indicates a mild irritation, it's a good guess that it can be classified as "Category 3."
3 Serious eye damage/eye irritation Category 1 Danger H318: Causes serious eye damage P305+P351+P338: IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
P280: Wear protective gloves/protective clothing/eye protection/face protection.
P310: Immediately call a POISON CENTER or doctor/physician. 		There are three test examples of the rabbit, guinea pig, and dog which show irritation below mild. However, there is one test example of the rabbit which shows corrosiveness and the test description of the example is reliable. Therefore, it will be appropriate to modify "Category 2A-2B"to "Category 1" in three-ministry GHS classification. In addition, the EU risk aphorism is also equivalent to "Category 1."
4 Respiratory sensitization - - - - - -
4 Skin sensitization - - - - - -
5 Germ cell mutagenicity Category 2 Warning H341: Suspected of causing genetic defects P308+P313: IF exposed or concerned: Get medical advice/attention.
P201: Obtain special instructions before use.
P202: Do not handle until all safety precautions have been read and understood.
P281: Use personal protective equipment as required.
P405: Store locked up.
P501: Dispose of contents/container to ... 		It is suggested that the active oxygen affects greatly from in vitro test result of Hydroquinone. Therefore, it is judged that the effect of active oxygen decreases at absorption/metabolic process by evaluating the reliability of two or more in vivo germ cell mutagenicity test positive finding in oral administration. Therefore, it can be said that weighting of proof is need for all the test results considering administration method. For in vivo somatic mutation original nature examination, weak influence is observed also in oral administration other than intraperitoneal administration, however, for the heritable mutagenicity test by oral administration, there is no positive result but negative result. "Category 2" is determined to be more proper than "Category 1B" from the weight of the evidence.
6 Carcinogenicity - - - - - -
7 Reproductive toxicity Not classified - - - - Although 3-Ministry GHS Classification is based on EHC (1994), it is a pretty old document (1955-1964), as pointed out in the public comment. Although these documents state that effects were identified, as a result of thorough review of Patty's Toxicology (2001) and SIDS (2002) published in the public comment, it has been confirmed that recent studies have not observed any reproductive toxicity in any of the developmental toxicity study using rats, developmental toxicity study using rabbits and 2 generation reproduction study using rats. Since these studies are based on USEPA Guidelines and OECD Guidelines, their data are reliable enough. Therefore, GHS Classification shall be changed from "Category 1B" to "Not classified."
8 Specific target organ toxicity - Single exposure Category 3 （Narcotic effects） Warning H336: May cause drowsiness or dizziness (narcotic effects) P304+P340: IF INHALED: Remove victim to fresh air and keep at rest in a position comfortable for breathing.
P403+P233: Store in a well-ventilated place. Keep container tightly closed.
P261: Avoid breathing dust/fume/gas/mist/vapours/spray.
P271: Use only outdoors or in a well-ventilated area.
P312: Call a POISON CENTER or doctor/physician if you feel unwell.
P405: Store locked up.
P501: Dispose of contents/container to ... 		"Category 1 (central nervous systems)" is corrected to "segment 3 (Narcotic effects)", as symptom is recovering thus is temporary. The rat case cited by the three-ministry GHS classification about "Category 1 (kidney)" is a case with a system difference and sex difference. Therefore, it is thought unreasonable to apply this to the decision of primates (humans) which species is different. Since human cases don't show neither harmful clinical influence nor change of blood and urine, it is judged that removal of kidney is appropriate.
9 Specific target organ toxicity - Repeated exposure Category 2 (liver) Warning H373: May cause damage to organs through prolonged or repeated exposure (liver) P260: Do not breathe dust/fume/gas/mist/vapours/spray.
P314: Get medical advice/attention if you feel unwell.
P501: Dispose of contents/container to ... 		About respiratory systems, there is the data from workers who were exposed to the mixture of Hydroquinone, Trimethylhydroquinone, and Retinene-Hydroquinone (EHC). However, within the limits described in SIDS, EHC, Patty's and Hazard Data Collection, there was no data that showed respiratory effects by inhalation exposure to Hydroquinone. Therefore, at the present stage, data is not sufficient for carrying out GHS classification about the repeated exposure on respiratory systems. As for blood system, there is animal test data where "hematological changes, such as anisocytosis, polychromasia and acidophilic erythroblasts" were observed within the guidance value ranges of "Category 1" (collection of hazard data, EHC). On the other hand, there is a case of human volunteers with no effect on blood (EHC), and this case is adopted in the section of evaluation on the human health risk in EHC. Therefore, although effects on blood system are observed in the study using rats, it can be judged that there is no effect on human blood system and it is considered equivalent to "Not classified" on blood system according to GHS classification. As for central nervous system, referring to EHC, the data which has become the rationale for three-minitsry GHS classification was turned out to be the case where "tremor and decreased activity were observed immediately after administration". Since this is regarded as the effect due to single exposure, it is considered proper to exclude central nervous system from the target organs for repeated exposure. As for liver, hepatotoxicity is observed in the study using mice within the guidance value ranges of "Category 2" and not observed in the study using animals such as rats. Moreover, there is no human case exhibiting hepatotoxicity. However, at present, it is considered proper to be defined as "Category 2 (liver)" based on the data on mice. As for kidney, although nephropathy is found in F344 male rats by repeated exposure of this substance, nephropathy is not found in F344 female rats, SD rats, Carworth rats, dogs and mice (Patty's). Moreover, it is indicated in SIDS, EHC, and Patty's that F344 female rats are sensitive to effects on kidney. Therefore, since nephropathy is considered to be a symptom peculiar to F344 male rats, it is considered proper to exclude kidney from the target organs for repeated exposure. From the above, the GHS classification for repetitive exposure is changed from "Category 1 (respiratory organs, blood system), Category 2 (central nervous system, liver, kidney)." to "Category 2 (liver)".
10 Aspiration hazard - - - - - -

ENVIRONMENTAL HAZARDS
Hazard class Classification Symbol Signal word Hazard statement Precautionary statement Rationale for the classification
11 Hazardous to the aquatic environment （Acute） - - - - - -
11 Hazardous to the aquatic environment （Long-term） - - - - - -


NOTE:
* Classification was conducted by relevant Japanese Ministries in accordance with GHS Classification Guidance for the Japanese Government, and is intended to provide a reference for preparing GHS labelling and SDS for users.
* This is a provisional English translation of classification results and is subject to revision without notice.
* The responsibility for any resulting GHS labelling and SDS referenced from this site is with users.

Reference：
Reference Manual
Definitions / Abbreviations
Model SDS by MHLW

 MHLW Website （in Japanese Only）

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