GHS Classification Result （Revision of the past classification result）

Chemical Name：Sodium hydroxide
CAS：1310-73-2

Result：
ID: 21B3010
Classifier: Ministry of Health, Labour and Welfare （MHLW）, Ministry of the Environment （MOE）
Year Classified: FY2009
Reference Manual: GHS Classification Guidance by the Japanese Government （March, 2009）

PHYSICAL HAZARDS
Hazard class Classification Symbol Signal word Hazard statement Precautionary statement Rationale for the classification
1 Explosives Not applicable - - - - There are no chemical groups associated with explosive properties present in the molecules.
2 Flammable gases （including chemically unstable gases） Not applicable - - - - Solid (GHS definition)
3 Aerosols Not applicable - - - - Not aerosol products
4 Oxidizing gases Not applicable - - - - Solid (GHS definition)
5 Gases under pressure Not applicable - - - - Solid (GHS definition)
6 Flammable liquids Not applicable - - - - Solid (GHS definition)
7 Flammable solids Not classified - - - - Not combustible (Hommel (1996))
8 Self-reactive substances and mixtures Not applicable - - - - There are no chemical groups present in the molecule associated with explosive or self-reactive properties.
9 Pyrophoric liquids Not applicable - - - - Solid (GHS definition)
10 Pyrophoric solids Not classified - - - - Not combustible (Hommel (1996))
11 Self-heating substances and mixtures Not classified - - - - Not combustible (Hommel (1996))
12 Substances and mixtures which, in contact with water, emit flammable gases Not classified - - - - Water solubility is 109 g/100 mL (20 degC) (ICSC (2000)), and the substance is stable against water.
13 Oxidizing liquids Not applicable - - - - Solid (GHS definition)
14 Oxidizing solids Classification not possible - - - - Classification is not possible since no data are available though the substance is inorganic compound containing oxygen. However, it is considered that the substance does not have oxidizing properties since sodium ion is a monovalent which is the most stable. (Refer to Guidance for Enterprises)
15 Organic peroxides Not applicable - - - - Inorganic compound
16 Corrosive to metals Classification not possible - - - - Test methods applicable to solid substances are not available.

HEALTH HAZARDS
Hazard class Classification Symbol Signal word Hazard statement Precautionary statement Rationale for the classification
1 Acute toxicity （Oral） Classification not possible - - - - 「Classification not possible due to lack of data. As relevant information, a LD50 value is 325 mg/kg for rabbits (SIDS (2002)).
1 Acute toxicity （Dermal） Classification not possible - - - - No data available.
1 Acute toxicity （Inhalation: Gases） Not applicable - - - - Solid (GHS definition)
1 Acute toxicity （Inhalation: Vapours） Classification not possible - - - - No data available.
1 Acute toxicity （Inhalation: Dusts and mists） Classification not possible - - - - No data available.
2 Skin corrosion/irritation Category 1 Danger H314: Causes severe skin burns and eye damage P301+P330+P331: IF SWALLOWED: Rinse mouth. Do NOT induce vomiting.
P303+P361+P353: IF ON SKIN （or hair）: Remove/Take off immediately all contaminated clothing. Rinse skin with water/shower.
P305+P351+P338: IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
P304+P340: IF INHALED: Remove victim to fresh air and keep at rest in a position comfortable for breathing.
P260: Do not breathe dust/fume/gas/mist/vapours/spray.
P264: Wash ... thoroughly after handling.
P280: Wear protective gloves/protective clothing/eye protection/face protection.
P310: Immediately call a POISON CENTER or doctor/physician.
P321: Specific treatment （see ... on this label）.
P363: Wash contaminated clothing before reuse.
P405: Store locked up.
P501: Dispose of contents/container to ... 		In a pig test using application of 2N (8%), 4N (16%) and 6N (24%) solutions on the abdominal region, gross blisters developed within 15 minutes of application and the 8 and 16% solutions produced severe necrosis in all epidermal layers. The 24% concentration produced numerous and severe blisters with necrosis extending deeper into the subcutaneous tissue (SIDS (2009)). Additionally, there is a report that severe necrosis occurred after application of a 5% solution to the skin of rabbits for 4-hour (ACGIH (7th, 2001)). Based on these data, the substance was classified into Category 1. As relevant information, the pH is 12 (0.05% w/w) (Merck (14th, 2006)). For humans, 0.5 - 4% solutions were irritating to the skin, and in skin irritation tests with a 0.5% solution, 55% and 61% of the volunteers showed positive skin irritation reactions (SIDS (2009)). In EU classification, the substance is classified into C; R35.
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. 		Based on a report that the corrosive concentration for rabbit eyes was 1.2% or higher than 2% (SIDS (2009)) and a pH of 12 (0.05% w/w) (Merck (14th, 2006)), the substance was classified into Category 1. For humans, there are numerous case reports that the accidental exposure to high concentrations of dusts and solutions caused severe eye damage (ACGIH (7th, 2001)) and that accidental contact with the eye leads to blindness (DFGOT vol. 12 (1999)). As relevant information, the substance is corrosive to skin and classified into C; R35 in EU classification.
4 Respiratory sensitization Classification not possible - - - - No data available.
4 Skin sensitization Not classified - - - - Male volunteers were exposed on their backs to concentrations of 0.063 - 1.0% of the substance. After 7 days the volunteers were challenged to a concentration of 0.125%. The irritant response correlated well with the concentration, but an increased response was not observed when the previously patch tested sites were rechallenged. Based on these results, sodium hydroxide has no skin sensitization potential. Furthermore sodium hydroxide has been used widely and for a long time, and no human cases of skin sensitization were reported, therefore, sodium hydroxide is not considered to be a skin sensitizer (SIDS (2009)). Based on this conclusion, the substance was classified as "Not classified".
5 Germ cell mutagenicity Not classified - - - - In bone marrow micronucleus tests by intraperitoneal administration to mice (in vivo somatic cell mutagenicity test), a significant increase of micronuclei was not observed (SIDS (2009)). In addition, in an oocyte aneuploidy induction test by intraperitoneal administration to mice (in vivo germ cell mutagenicity test), any evidence that suggested a chromosome non-disjunction was not observed (SIDS (2009)). Since there findings indicate negative results for in vivo somatic cell and germ cell mutagenicity tests, the substance was classified as "Not classified". As relevant information, from in vitro mutagenicity tests, there are reports of a negative Ames test (SIDS (2009)) and a false-positive CHO K1 cell chromosomal aberration test (SIDS (2009)).
6 Carcinogenicity Classification not possible - - - - Although there is a report of a negative result in a rat carcinogenicity test by oral administration for 12 weeks (DFGOT vol. 12 (1999)), classification was not possible due to lack of sufficient data.
7 Reproductive toxicity Classification not possible - - - - No data available.
8 Specific target organ toxicity - Single exposure Category 1 (respiratory system) Danger H370: Causes damage to organs (respiratory system) P307+P311: IF exposed: Call a POISON CENTER or doctor/physician.
P260: Do not breathe dust/fume/gas/mist/vapours/spray.
P264: Wash ... thoroughly after handling.
P270: Do not eat, drink or smoke when using this product.
P321: Specific treatment （see ... on this label）.
P405: Store locked up.
P501: Dispose of contents/container to ... 		Based on a report that acute exposures involving inhalation of dusts or mists may cause mucous membrane irritation with subsequent cough and dyspnea; and that intense exposure may result in pulmonary edema and shock (PATTY (5th, 2001)), the substance was classified into Category 1 (respiratory system). As relevant information, there is a report that dust formation is unlikely because of the substance's hygroscopic properties and negligible vapour pressure (SIDS (2009)). There is a report of 28 accidental ingestion cases in which approximately 50 - 200 mL of a 25 - 37% solution of the substance was ingested and injury to the upper gastrointestinal tract and esophagus was observed (SIDS (2009)). Additionally, there are numerous case report of serious accidental or suicidal poisoning in which the substances caused severe corrosion of mouth, throat, tongue and oesophagus (DFGOT vol. 12 (1999)).
9 Specific target organ toxicity - Repeated exposure Classification not possible - - - - There is a report that no animal data are available for repeated dose toxicity tests by oral, dermal, inhalation and other routes of exposure for the substance (SIDS (2009)). There is very little human data available. Classification was not possible due to lack of data. There is a report that following repeated inhalation exposure to aerosols of the substance, rats suffered pulmonary damage (ACGIH (7th, 2001)). This data was not used as the basis of classification since the exposure concentrations are unknown. As relevant information, there is a report that dust formation is unlikely because of the hygroscopic properties and negligible vapour pressure of the substance (SIDS (2009)).
10 Aspiration hazard Classification not possible - - - - No data available.

ENVIRONMENTAL HAZARDS
Hazard class Classification Symbol Signal word Hazard statement Precautionary statement Rationale for the classification
11 Hazardous to the aquatic environment （Acute） Category 3 - - H402: Harmful to aquatic life P273: Avoid release to the environment.
P501: Dispose of contents/container to ... 		Classified into Category 3 from its 48h-LC50 = 40 mg/L for Crustacea (Cenodaphnia quadrangular) (SIDS, 2004, etc).
11 Hazardous to the aquatic environment （Long-term） Not classified - - - - Classified into Not classified since the toxicity is mitigated in environmental water by buffer action though it is considered to be a factor of toxicity that water solution becomes a strong base.
12 Hazardous to the ozone layer Classification not possible - - - - This substance is not listed in Annexes to the Montreal Protocol.


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 Label by MHLW

 MHLW Website （in Japanese Only）
Model SDS by MHLW

 MHLW Website （in Japanese Only）

To GHS Information