Registration Dossier

Data platform availability banner - registered substances factsheets

Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Description of key information

Magnesium isopropanolate rapidly hydrolyzes in aqueous environments. Toxicity is mediated by its degradation products isopropanol and Mg(OH)2 and assessed for these products.

Isopropanol

Both an in vivo LLNA equivalent or similar to OECD guideline and each of a 3 test in vitro battery equivalent or similar to OECD guidelines and comprising the complete AOP for skin sensitization were negative.

Mg(OH)2

Based on a weight of evidence approach using both animal testing and human information magnesium hydroxide is not regarded and not classified as a skin sensitizer. 

Key value for chemical safety assessment

Respiratory sensitisation

Endpoint conclusion
Additional information:

Isopropanol

Isopropanol was tested upto a concentration of 50% and found negative in a LNNA equivalent or similar to OECD Guideline 429. Isopropanol was tested negative in each of a DPRA, KeratinoSens assay, and U937-CD86 assay. The test battery was carried out on 145 chemicals and the study documented a good sensitivity, specificity and accuracy for its approach when validated against the in vivo LLNA.

Mg(OH)2

Based on a weight of evidence approach using both animal testing and human information, magnesium hydroxide is not regarded and not classified as a skin sensitizer. 

Although a guideline-conform local lymph node assay showed a positive response, there are a number of reasons to suggest that it is highly unlikely that magnesium hydroxide is a skin sensitizer. An expert opinion has been provided from the Informationsverbund Dermatologischer Kliniken (IVDK; Schnuch, A. 2010). The IVDK is a network of over 50 dermatological hospitals, and was formed to monitor and survey the development of contact allergies. Despite 20 years of observations in 192,421 patients they have yet to observe a case of a contact allergy caused by magnesium hydroxide. Furthermore, no case of contact allergy to magnesium hydroxide has been reported in the world literature, despite extensive exposure of the general population to the substance. Some reports on flame retardants address magnesium hydroxide toxicity, and no sensitizing effects are reported (DFE (EPA), 2008; NAP, 2000). In addition to this, human health questionnaires were distributed among eight magnesium hydroxide producing companies where, overall, 457 workers are exposed to Magnesium hydroxide,182 of those are exposed continuously and 227 are exposed intermittently. These workers were questioned on any adverse effects or health problems they may have experienced due to exposure; these included allergy or occupational asthma. Among all the workers surveyed, there were no reported cases, from any of the 457 workers, of health problems or adverse effects experienced through exposure.

Moreover, the results of a guinea pig maximisation test (GPMT) performed with magnesium chloride were obtained from the magnesium chloride consortium. The results presented show that magnesium chloride was negative in the GPMT. As any possible skin sensitizing potential of magnesium hydroxide is likely to stem from the cation rather than the hydroxide anion, the outcome of this test provides additional evidence that magnesium ions should not be regarded as skin sensitizers. Regarding the hydroxide portion of the compound, there is ample evidence that hydroxides of other metals are not skin sensitizers in the literature (NICNAS, 2003; Banerjee et. al., 2003; DFE (EPA), 2008).

False positives in the LLNA assay are not uncommon, and indeed the LLNA was judged to be no more than 90 % accurate during its validation (Basketter et. al., 2010). On this basis, certain substances have not been classified as contact sensitizers despite giving positive responses in the LLNA test. These include Copper chloride (Basketter and Scholes, 1992), Sodium lauryl sulphate (Loveless et. al., 1996; Montelius et. al., 1994), Benzalkonium chloride (Basketter et. al., 2004) and Ethanol (Basketter et. al., 2010).

Given the combination of the epidemiological data, the negative guinea pig maximisation test with magnesium chloride and the history of false positives using the LLNA, the weight of evidence suggests that the positive results obtained in the LLNA are inaccurate and, thus, a sensitizing effect of magnesium hydroxide is unlikely. Therefore, magnesium hydroxide should not be classed as a skin sensitizer.

Justification for classification or non-classification

Magnesium isopropanolate

Magnesium isopropanolate rapidly hydrolyzes in aqueous environments. Toxicity is mediated by its degradation products isopropanol and Mg(OH)2 and assessed for these products.

Both hydrolysis products should not be classified for sensitisation. Based on the available information, magnesium isopropanolate thus does not have to be classified and has no obligatory labelling requirement for sensitisation.

Isopropanol

Both an in vivo LLNA equivalent or similar to OECD guideline and each of a 3 test in vitro battery equivalent or similar to OECD guidelines and comprising the complete AOP for skin sensitization were negative.

Accordingly, isopropanol is not sensitizing to skin and should not be classified as a skin sensitizer.

Mg(OH)2

Based on a weight of evidence approach using both animal testing and human information magnesium hydroxide is not regarded and not classified as a skin sensitizer.

An expert opinion has been provided from the Informationsverbund Dermatologischer Kliniken (IVDK; Schnuch, A. 2010), which states that they have yet to observe a case of contact allergy caused by magnesium hydroxide. Also, despite extensive exposure of the general population to the substance, no case of contact allergy to magnesium hydroxide has been reported in the world literature. Furthermore, evidence that the magnesium portion of the compound is not a a skin sensitizer was obtained from the results of a guinea pig maximisation test (GPMT) that was performed on behalf of the magnesium chloride consortium, and shows a negative result. Regarding the hydroxide portion of the compound, there is ample evidence in the literature that hydroxides of other metals are not skin sensitizers (NICNAS, 2003; Banerjee et. al., 2003; DFE (EPA), 2008). False positives in LLNA assays are not uncommon, and the LLNA was judged to be no more than 90 % accurate during its validation (Basketter et. al., 2010). Given the combination of the epidemiological data, the magnesium chloride test and the history of false positives using the LLNA, there is a basis for supporting that the positive results obtained in the LLNA test are inaccurate and, thus, a sensitizing effect of magnesium hydroxide is highly unlikely. Therefore magnesium hydroxide should not be classified as a skin sensitizer.