Boehmite (Al(OH)O)

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

There are no studies available on skin sensitisation for Boehmite. Therefore data from aluminium compounds were taken into account by read across following a structural analogue approach.

The results on the sensitisation potential of aluminium hydroxide from OECD TG #406 test (LAB Research Ltd, 2010) indicate that aluminium hydroxide is not a strong skin sensitizer. Data presented in IUCLID (Aluminium hydroxide, IUCLID, 2000) provide support for a low sensitising potential. The lack of detail that is available about the study, however, limits its use for hazard identification.Data from a recently conducted guideline-compliant test on the skin irritative properties of aluminium hydroxide (Lab Research, 2009a; Klimisch Score 1) indicate that aluminium hydroxide does not cause irritative effects after a single application to rabbit skin. These results support a low sensitisation potential for this substance. Data published by Lansdown (1973) indicate that repeated dermal application of 10% aluminium hydroxide to three different species of animals using an open epicutaneous method did not cause any skin symptoms which is also suggestive of a low sensitisation potential.Results from animal studies with designs similar to OECD TG #429 and #406 (Basketter et al.,1999; Magnusson and Kligman, 1969) provide evidence that aluminium chloride and/or aluminium chloride hexahydrate have low sensitisation potential after epicutaneous and intradermal administration to laboratory animals. 

Overall, the evidence supports a low sensitisation potential for aluminium hydroxide.

The read-across from aluminium hydroxide and aluminium chloride hexahydrate shows that Boehmite does not require classification as a skin sensitizer.

 

Migrated from Short description of key information:
Overall, the read-across from a GLP study according to OECD 406 (LAB Research Ltd., 2010) does not support a sensitisation potential for Boehmite.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

There are no studies available on respiratory sensitisation for Boehmite. Therefore data from aluminium compounds were taken into account by read across following a structural analogue approach.

 

Based on an assessment of the available data on aluminium compounds, the weight of evidence does not support an important role for alumina in the development of potroom asthma. The weight of evidence supports an irritative effect of the fluoride component of pot emissions (Taiwoet al., 2006; Søysethet al., 1992, 1994, 1997; Sorgdrageret al., 1998; Kongerud and Samuelsen, 1991). Work-related asthmatic symptoms in potroom workers may result, in part, from non-specific “irritant” and also from “allergic inflammation” reactions (Sariҫet al.,1986; Mackayet al., 1990; Eklundet al.,1989). The relative contributions of these mechanisms are unclear and individuals with pre-existing bronchial hyper-responsiveness or a history of respiratory allergy may be at increased risk (Barnardet al.,2004; Kongerud and Samuelsen, 1991).

Some studies among aluminium welders have shown decrements in lung function (Fishwick et al.,2004; Abbate et al., 2003; Nielsen et al., 1993) and others have not (Sjogren and Ulfvarson, 1985; Kilburn et al., 1989). Sjogren and Ulfvarson (1985) observed an association between respiratory symptoms and exposures to ozone among welders. The small sample sizes, questionable comparability of referent groups (e.g. Kilburn et al., 1989) and possible (residual) confounding by smoking and irritative co-exposures such as ozone and other fume constituents are limitations of the available studies.

Results from a few case reports, notably Vandenplas et al.(1998) (also Park et al.,1996 and Burge et al., 2000) indicate that respiratory sensitization on exposure to poorly soluble aluminium substances can occur, but results from larger studies (Fritschi et al., 2001; Beach et al., 2001; Taiwo et al., 2006) suggest that it is rare. 

The only animal study identified that employed a guideline assay with results relevant to the respiratory sensitization endpoint and the target substances (the LLNA; Basketter et al., 1999) found that aluminium chloride, a more soluble aluminium substance, did not possess “significant ability to sensitize the skin”. As discussed by ECHA (2008):“In combination with other data it might be possible to conclude in a WoE assessment that chemicals that (at an appropriate test concentration and test conditions, i.e. skin penetration should have occurred) are negative in the LLNA, as well as being considered as not being skin sensitizers, can also be regarded as lacking the potential to cause allergic sensitisation of the respiratory tract.” (ECHA, 2008). The mouse study of Ichinose et al.(2008) supports a weak allergic inflammatory potential for Al₂O₃. In addition, the guideline compliant study by Lab Research Ltd. (2010) that tested the skin sensitisation potential of Al(OH)₃reported negative results, thereby contributing to the weight of evidence supporting a low sensitizing potential for the poorly soluble target substances

Migrated from Short description of key information:
The read-across from aluminium compounds within a weight of evidence approach shows that Boehmite does not require classification as a respiratory sensitizer.

Justification for classification or non-classification

The current weight of evidence supports a low respiratory and skin sensitizing potential for Boehmite.

Therefore, according toDSD (67/548/EEC) or CLP (1272/2008/EC) classification criteria for sensitisation, no classification is required.