NITE - Chemical Management Field

GHS Classification Results by the Japanese Government

GENERAL INFORMATION

Item	Information
CAS RN	409-21-2
Chemical Name	Silicon carbide whisker
Substance ID	R02-B-065-MHLW
Classification year (FY)	FY2020
Ministry who conducted the classification	Ministry of Health, Labour and Welfare (MHLW)/Ministry of the Environment (MOE)
New/Revised	Revised
Classification result in other fiscal year	FY2006
Download of Excel format	Excel file

REFERENCE INFORMATION

Item	Information
Guidance used for the classification (External link)	GHS Classification Guidance for the Japanese Government (FY2019 revised edition (Ver. 2.0))
UN GHS document (External link)	UN GHS document
Definitions/Abbreviations (Excel file)	Definitions/Abbreviations
Model Label by MHLW (External link)	MHLW Website (in Japanese Only)
Model SDS by MHLW (External link)	MHLW Website (in Japanese Only)
OECD/eChemPortal (External link)	eChemPortal

PHYSICAL HAZARDS

Hazard class		Classification	Pictogram Signal word	Hazard statement (code)	Precautionary statement (code)	Rationale for the classification
1	Explosives	Not classified (Not applicable)	- -	-	-	There are no chemical groups associated with explosive properties present in the molecule. It was classified as "Not classified."
2	Flammable gases	Not classified (Not applicable)	- -	-	-	Solid (GHS definition). It was classified as "Not classified."
3	Aerosols	Not classified (Not applicable)	- -	-	-	Not aerosol products. It was classified as "Not classified."
4	Oxidizing gases	Not classified (Not applicable)	- -	-	-	Solid (GHS definition). It was classified as "Not classified."
5	Gases under pressure	Not classified (Not applicable)	- -	-	-	Solid (GHS definition). It was classified as "Not classified."
6	Flammable liquids	Not classified (Not applicable)	- -	-	-	Solid (GHS definition). It was classified as "Not classified."
7	Flammable solids	Not classified	- -	-	-	It was classified as "Not classified" from information that it is not combustible (HSDB (Access on May 2020)).
8	Self-reactive substances and mixtures	Not classified (Not applicable)	- -	-	-	There are no chemical groups present in the molecule associated with explosive or self-reactive properties. It was classified as "Not classified."
9	Pyrophoric liquids	Not classified (Not applicable)	- -	-	-	Solid (GHS definition). It was classified as "Not classified."
10	Pyrophoric solids	Not classified	- -	-	-	It was classified as "Not classified" from information that it is not combustible (HSDB (Access on May 2020)).
11	Self-heating substances and mixtures	Not classified	- -	-	-	It was classified as "Not classified" from information that it is not combustible (HSDB (Access on May 2020)).
12	Substances and mixtures which, in contact with water, emit flammable gases	Not classified	- -	-	-	It contains a metalloid (Si), but it was classified as "Not classified" because it is estimated that it does not react vigorously with water from obtained information that it is insoluble in water (RAC Background Document (2018)).
13	Oxidizing liquids	Not classified (Not applicable)	- -	-	-	Solid (GHS definition). It was classified as "Not classified."
14	Oxidizing solids	Not classified (Not applicable)	- -	-	-	Inorganic compounds containing no oxygen or halogen atoms. It was classified as "Not classified."
15	Organic peroxides	Not classified (Not applicable)	- -	-	-	Inorganic compound. It was classified as "Not classified."
16	Corrosive to metals	Classification not possible	- -	-	-	Classification is not possible because test methods applicable to solid substances are not available.
17	Desensitized explosives	Not classified (Not applicable)	- -	-	-	There are no chemical groups associated with explosive properties present in the molecule. It was classified as "Not classified."

HEALTH HAZARDS

Hazard class		Classification	Pictogram Signal word	Hazard statement (code)	Precautionary statement (code)	Rationale for the classification
1	Acute toxicity (Oral)	Classification not possible	- -	-	-	[Rationale for the Classification] Classification not possible due to lack of data.
1	Acute toxicity (Dermal)	Classification not possible	- -	-	-	[Rationale for the Classification] Classification not possible due to lack of data.
1	Acute toxicity (Inhalation: Gases)	Not classified	- -	-	-	[Rationale for the Classification] Solid (GHS definition). It was classified as "Not classified."
1	Acute toxicity (Inhalation: Vapours)	Classification not possible	- -	-	-	[Rationale for the Classification] Classification not possible due to lack of data.
1	Acute toxicity (Inhalation: Dusts and mists)	Classification not possible	- -	-	-	[Rationale for the Classification] Classification not possible due to lack of data.
2	Skin corrosion/irritation	Classification not possible	- -	-	-	[Rationale for the Classification] There was a description of (1), but the classification was not possible due to lack of data. [Reference Data, etc.] (1) In an acute toxicity test by dermal administration to rats according to OECD TG402, no skin irritation was found (REACH registration dossier (Access on August 2020)).
3	Serious eye damage/eye irritation	Classification not possible	- -	-	-	[Rationale for the Classification] Classification not possible due to lack of data.
4	Respiratory sensitization	Classification not possible	- -	-	-	[Rationale for the Classification] Classification not possible due to lack of data.
4	Skin sensitization	Classification not possible	- -	-	-	[Rationale for the Classification] Classification not possible due to lack of data.
5	Germ cell mutagenicity	Classification not possible	- -	-	-	[Rationale for the Classification] Classification not possible due to lack of data. [Evidence Data] (1) There were no in vivo data. (2) As for in vitro, when silicon carbide whiskers (SiCW) were used as the test substance, DNA strand break tests using human lung cancer cells and cultured mammalian cells (CHL V79) and a chromosomal aberration test with human fetal embryo cells were positive. Among these, in a DNA strand break test using four kinds of SiCW (geometrical mean length: 12-14 micrometer, geometrical mean diameter: 0.7-0.9 micrometer), their DNA breaking potential was at the same level as crocidolite (asbestos), the positive control. [Reference Data, etc.] (3) Extracts of silicon carbide were reported to be negative in a bacterial reverse mutation test (EU CLP CLH (2018), REACH registration dossier (Access on July 2020)). (4) For nanoparticles, whiskers, and fibers of silicon carbide, detection of ability to induce cell transformation, chromosomal aberrations, micronuclei, etc. was conducted using in vitro cultured mammalian cells, and negative and positive knowledge was obtained (IARC 111 (2017), ACGIH (7th, 2001), MAK (DFG) vol.8 (1997)). (5) A chromosomal aberration test and a micronucleus test with cultured mammalian cells on silicon carbide fibers (details unknown) gave positive results (Recommendation of Occupational Exposure Limits (Japan Society For Occupational Health (JSOH), 2019)).
6	Carcinogenicity	Category 1B	Danger	H350	P308+P313 P201 P202 P280 P405 P501	[Rationale for the Classification] There was no available report on exposure to this substance in humans. It was classified in Category 1B based on (1) - (5). [Evidence Data] (1) As for classification results by domestic and international organizations, IARC classified silicon carbide whiskers (diameter < 5 micrometer, length > 20 micrometer) in Group 2A, and fibrous silicon carbide (particle diameter > 5 micrometer, width < 3 micrometer, aspect ratio > 3) in Group 2B (IARC 111 (2017)). ACGIH classified silicon carbide in A2 (ACGIH (7th, 2003)), and silicon carbide whiskers were classified in Group 2A by the Japan Society for Occupational Health (JSOH) (Recommendation of Occupational Exposure Limits (Japan Society For Occupational Health (JSOH)) (proposed in 2019)), and 2 in MAK (DFG) (DFG List of MAK and BAT Values 2019). (2) Among two carcinogenicity tests by 1-year inhalation exposure of rats to silicon carbide whiskers, lung cancer, lung adenoma, and pleural mesothelioma were observed in one test, and no lung tumor was found in the other one (OEL Documentations (Japan Society For Occupational Health (JSOH), 2019), IARC 111 (2017)). (3) Among four tests by intraperitoneal injection of silicon carbide whiskers to rats, incidences of mesothelioma in the abdominal cavity were observed in three tests. And in a test by intrapleural injection of silicon carbide whiskers to rats, an incidence of pleural mesothelioma was found (OEL Documentations (Japan Society For Occupational Health (JSOH), 2019)). One study by intraperitoneal administration to female rats gave a negative result (IARC 111 (2017)). (4) In a study by intratracheal administration of two kinds of silicon carbide whiskers to female rats, no treatment-related tumor formation was observed, but IARC judged that it was a limited study due to the short duration of the treatment (IARC 111 (2017)). (5) Studies on silicon carbide whiskers demonstrated biopersistence in the rat lung. IARC noted the lack of studies on the translocation of silicon carbide materials to the pleural cavity in experimental animals. Pulmonary exposure to silicon carbide whiskers in experimental animals was associated with lung cell injury, inflammation, and fibrotic responses. Oxidative stress was reported in studies in vitro. One study of genotoxicity demonstrated chromosomal aberrations in human embryonic lung cells exposed to silicon carbide whiskers. The few available studies reported data which were fully consistent with the mechanisms of carcinogenicity proposed for asbestos and erionite (IARC 111 (2017)).
7	Reproductive toxicity	Classification not possible	- -	-	-	[Rationale for the Classification] Classification was not possible due to lack of data.
8	Specific target organ toxicity - Single exposure	Category 1 (lung)	Danger	H370	P308+P311 P260 P264 P270 P321 P405 P501	[Rationale for the Classification] There was no report on acute exposure to this substance in humans. Based on (1) and (2), an intratracheal administration test was used as an alternative to an inhalation exposure test, and although it was not possible to make a classification based on the dose, it was reported that this substance had larger inflammatory and fibrosing effects than asbestos. Therefore, it was classified in Category 1 (lung). A new information source was used and the classification results were changed from the previous classification. [Evidence Data] (1) In a recent report, observations of the lung lesions up to 6 months after intratracheal injections of 2 mg of silicon carbide whiskers (SiCW) (geometric mean diameter: 0.3 micrometer, geometric mean length: 5.1 micrometer), crystalline silica, and crocidolite (asbestos), revealed that lung inflammation and fibrosis were transient with SiCW, but persistent with crystalline silica and crocidolite (OEL Documentations (Japan Society for Occupational Health (JSOH), 2019)). (2) Rats were intratracheally injected with 2 kinds of SiCW (SiCW1: geometric mean diameter of 0.8 micrometer, geometric mean length of 18.1 micrometer, SiCW2: geometric mean diameter of 1.5 micrometer, geometric mean length of 19.0 micrometer) and crocidolite (asbestos) (0.1 or 0.5 mg/rat), and inflammatory cells in the broncoalveolar lavage fluid were examined 1, 7, and 28 days after the injection. The result showed that SiCW1 caused an increase in macrophages in the broncoalveolar lavage fluid from 7 to 28 days after the injection and SiCW2 caused an increase in macrophages by about half. After 18 months, both SiCW1 and SiCW2 caused granuloma in low and high dose groups, while crocidolite caused granuloma only in a high dose group. It was shown that SiCW had more inflammatory and fibrosing effects than asbestos (OEL Documentations (Japan Society for Occupational Health (JSOH), 2019)).
9	Specific target organ toxicity - Repeated exposure	Category 1 (lung)	Danger	H372	P260 P264 P270 P314 P501	[Rationale for the Classification] Based on (1), it was classified in Category 1 (lung). [Evidence Data] (1) In a study with rats by inhalation exposure to 0.09 to 60.5 mg/m3 of silicon carbide whiskers (fibrous material with a mean diameter of 0.577 micrometer and a length of 4.68 micrometer) for 13 weeks (6 hours/day, 5 days/week) (converted guidance value: 0.0001 to 0.04 mg/L, within the range for Category 1 or Category 2), a concentration-dependent increase in the incidence of pulmonary lesions (inflammatory lesions, lymphoid hyperplasia in bronchial and mediastinal lymph nodes, bronchiolar, alveolar and pleural wall thickening and pleural fibrosis) was observed (ACGIH (7th, 2003), RAC (2018)). [Reference Data, etc.] (2) Pneumoconiosis, shadow on the X ray of the lungs (nodular shadow, etc.), changes in pulmonary function parameters, etc. in workers handling silicon carbide were reported (ACGIH (7th, 2003), MAK (DFG) (2019)). (3) For silicon carbide, the ACGIH sets the TLV-TWA separately for nonfibrous particles and fibrous forms. The TLV-TWA for nonfibrous particles (containing no asbestos and < 1% crystalline silica) was 10 mg/m3 (inhalable particles mass), 3 mg/m3 (respirable particle mass). The TLV-TWA for fibrous forms including whiskers was 0.1 f/cc (respirable fibers) (ACGIH (7th, 2003)).
10	Aspiration hazard	Classification not possible	- -	-	-	[Rationale for the Classification] Classification not possible due to lack of data.

ENVIRONMENTAL HAZARDS

Hazard class		Classification	Pictogram Signal word	Hazard statement (code)	Precautionary statement (code)	Rationale for the classification
11	Hazardous to the aquatic environment Short term (Acute)	-	- -	-	-	-
11	Hazardous to the aquatic environment Long term (Chronic)	-	- -	-	-	-
12	Hazardous to the ozone layer	-	- -	-	-	-

NOTE:

GHS Classification Result by the Japanese Government is intended to provide a reference for preparing a GHS label or SDS for users. To include the same classification result in a label or SDS for Japan is NOT mandatory.
Users can cite or copy this classification result when preparing a GHS label or SDS. Please be aware, however, that the responsibility for a label or SDS prepared by citing or copying this classification result lies with users.
This GHS classification was conducted based on the information sources and the guidance for classification and judgement which are described in the GHS Classification Guidance for the Japanese Government etc. Using other literature, test results etc. as evidence and including different content from this classification result in a label or SDS are allowed.
Hazard statement and precautionary statement will show by hovering the mouse cursor over a code in the column of "Hazard statement" and "Precautionary statement," respectively. In the excel file, both the codes and statements are provided.
A blank or "-" in the column of "Classification" denotes that a classification for the hazard class was not conducted in the year.
An asterisk “*” in the column of “Classification” denotes that “Not classified (or No applicable)” and/or “Classification not possible” is applicable. Details are described in the column of “Rationale for the classification”. If no English translation is available for “Rationale for the classification,” please refer to the Japanese version of the results.

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