Slags, ferrochromium-manufg.

Carcinogenicity

Description of key information

The amorphous glass phase of the slag consists of practically insoluble silicates. The levels of dissolving hexavalent chromium are below  the detection limits and there is no carcinogenic crystalline silica or fibrous silicates in the slag. The animal studies of amorphous silicas or non-fibrous silicates have not shown carcinogenic activity. Human data from occupational exposures to amorphous silica or clay-like silicates like kaolin or bentonite have not shown increased cancer risk from inhalation of these materials. Similar experience exists also from the workers in the ferrochrome industry where there exist potential to be exposed also to ferrochromium slag.
IARC (1997) has evaluated silica as not classifiable as a carcinogen and OECD SIDS (2004) concludes that the “cancerogenic potential of synthetic amorphous silicas/silicates can be considered as negligible”. 

Justification for classification or non-classification

The ferrochromium slag is not classificable for carcinogenicity.

Additional information

No carcinogenicity data of ferrochromium slag exists.

The amorphous glass phase of FeCr-slag consists of practically insoluble silicates, and therefore it is seen justified to use read-across to studies on synthetic amorphous silica, calcium silicate, sodium aluminium silicate, kaolin (an Al-silicate) and nonfibrous glass (containing Ca-, Al, Mg- and borosilicates).

Al, Ca, Mg, Fe, Cr which are present as silicates or metals (Fe and Cr) are practically insoluble. The levels of dissolving hexavalent chromium are below the detection limits. There is no carcinogenic crystalline silica or fibrous silicates in the slag. The bioavailable form of synthetic amorphous silica and silicates is the dissolved form which exists as monosilicic acid. It is assumed that a similar effects profile for them exists. The animal studies of amorphous silicas or non-fibrous silicates have not shown carcinogenic activity. Human data from occupational exposures to amorphous silica or clay-like silicates like kaolin or bentonite have not shown increased cancer risk from inhalation of these materials. Similar experience exists also from the workers in the ferrochrome industry where there exist potential to be exposed also to ferrochromium slag.

IARC (1997) has evaluated silica as not classifiable as a carcinogen and OECD SIDS (2004) concludes that the “cancerogenic potential of synthetic amorphous silicas/silicates can be considered as negligible”.

The available data on the carcinogenicity of insoluble chromium do not show any clear carcinogenic effects. Trivalent chromium has been evaluated for carcinogenicity by IARC, WHO, ACGIH and US EPA, and none of these evaluations have found any evidence for chromium metal or Cr(III) being a potential carcinogen.