Slags, ferronickel-manufg.

Carcinogenicity

Description of key information

Nickel metal is the only classified carcinogen (as Carcinogen, Category 2) of the constituents of slags, ferronickel-manufg. It is suspected to be tumorigenic by the inhalation route, but no concrete evidence exists (see IARC_Nickel. pdf) for this. If we were to assume that ferronickel slags are mixtures, in order for them to be characterised as Carcinogen Category 2 (inhalation), then Nickel content should be at least 1% w/w, according to the CLP regulation (1272/2008). This is well above the maximum metallic Nickel content of the slags. Additionally, Nickel metal is chemically bound and trapped in the slag matrix mainly in the form of ferronickel granules. So, the slags should not be classified as carcinogens.
Of the other constituents, only SiO2 has a potential for carcinogenicity, but only in the crystalline phase and in ultra fine particle size. It was proven with the particle size distribution study and XRD analyses of the slag that no SiO2 exists in the crystalline phase, while particles below 10μm are only around 1% of the material. The fine particle fraction of various grades of Ferronickel Slags was analysed with XRD using Rietveld quantitative phase analysis to determine the respirable crystalline silica (RCS) content. As a result no RCS was detected, so it is safely assumed that the SiO2 in the substance is amorphous. The possibility of existence of hexavalent chromium species was examined in various grades of Ferronickel slags (Electric Arc Furnace Slag, Converter Slag) from a number of facilities that produce them. Using alkaline digestion (EPA method 3060A) and colorimetry (EPA method 7196A), no hexavalent chromium was detected. Therefore, it is assumed that all chromium in Ferronickel slags is in the trivalent form.
Additionally, two studies on the genetic toxicity of a ferronickel slag sample with a high content of Nickel metal showed no mutagenic effects.
The classification of slags, ferronickel-manufg. for carcinogenicity is not justified.

Justification for classification or non-classification

Nickel metal is the only classified carcinogen (as Carcinogen, Category 2) of the constituents of slags, ferronickel-manufg. It is suspected to be tumorigenic by the inhalation route, but no concrete evidence exists (see attached IARC_Nickel. pdf) for this. If we were to assume that ferronickel slags are mixtures, in order for them to be characterised as Carcinogen Category 2 (inhalation), then Nickel content should be at least 1% w/w, according to the CLP regulation (1272/2008). This is well above the maximum metallic Nickel content of the slags. Additionally, Nickel metal is chemically bound and trapped in the slag matrix mainly in the form of ferronickel granules. So, the slags should not be classified as carcinogens. Of the other constituents, only SiO2 has a potential for carcinogenicity, but only in the crystalline phase and in ultra fine particle size. It was proven with the particle size distribution study and XRD analyses of the slag that practically no SiO₂exists in the respireable crystalline phase, while particles below 10μm are only around 1% of the material. The fine particle fraction of various grades of Ferronickel Slags was analysed with XRD using Rietveld quantitative phase analysis to determine the respirable crystalline silica (RCS) content. As a result no RCS was detected, so it is safely assumed that the SiO2 in the substance is amorphous.The possibility of existence of hexavalent chromium species was examined in various grades of Ferronickel slags (Electric Arc Furnace Slag, Converter Slag) from a number of facilities that produce them. Using alkaline digestion (EPA method 3060A) and colorimetry (EPA method 7196A), no hexavalent chromium was detected.Therefore, classification of slags, ferronickel-manufg. for carcinogenicity is not justified.

Additional information

Nickel metal is the only classified carcinogen (as Carcinogen, Category 2) of the constituents of slags, ferronickel-manufg. It is suspected to be tumorigenic by the inhalation route, but no concrete evidence exists (see IARC_Nickel.pdf) for this. If we were to assume that ferronickel slags are mixtures, in order for them to be characterised as Carcinogen Category 2 (inhalation), then Nickel content should be at least 1% w/w, according to the CLP regulation (1272/2008). This is well above the maximum metallic Nickel content of the slags. Additionally, Nickel metal is chemically bound and trapped in the slag matrix mainly in the form of ferronickel granules. So, the slags should not be classified as carcinogens. Of the other constituents, only SiO2 has a potential for carcinogenicity, but only in the crystalline phase and in ultra fine particle size. It was proven with the particle size distribution study and XRD analyses of the slag that no SiO2 exists in the crystalline phase, while particles below 10μm are only around 1% of the material. The fine particle fraction of various grades of Ferronickel Slags was analysed with XRD using Rietveld quantitative phase analysis to determine the respirable crystalline silica (RCS) content. As a result no RCS was detected, so it is safely assumed that the SiO2 in the substance is amorphous.The possibility of existence of hexavalent chromium species was also examined in various grades of Ferronickel slags (Electric Arc Furnace Slag, Converter Slag) from a number of facilities that produce them. Using alkaline digestion (EPA method 3060A) and colorimetry (EPA method 7196A), no hexavalent chromium was detected. Therefore, it is assumed that all chromium in Ferronickel slags is in the trivalent form.Therefore, classification of slags, ferronickel-manufg. for carcinogenicity is not justified.