2-chlorophenyl isocyanate

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Additional information:

The Guinea Pig Maximization Test according OECD Guideline 406 was performed on male guinea pigs to determine whether the test substance exhibits skin-sensitizing properties.

The study was conducted with the following test substance concentrations:

Intradermal induction: 2.5%, Topical induction: 5% and Challenge: 3%.

For the induction and the challenge treatment the test substance was formulated in corn oil (dried) to yield a solution.

The challenge using a 3% test substance formulation led to skin effects in all animals in the treatment group and in none of the animals in the control group.

In summary, under the conditions of the maximization test and with respect to the evaluation criteria the test substance therefore thus exhibits a skin-sensitization potential (Stropp, 1997).

Migrated from Short description of key information:
Under the conditions of the maximization test the test substance exhibits a skin-sensitization potential (Stropp, 1997).

Respiratory sensitisation

Endpoint conclusion

Additional information:

Due to regulation 67/548/EEC isocyanates have to be classified as respiratory sensitisers with R 42. Based on comparative analysis regarding studies on skin sensitisation with other isocyanates (p-isopropylphenylisocyanate_CAS 31027-31-3, n-butylisocyanante_CAS 111-36-4, 3,4-dichlorphenylisocyanante_CAS 102-36-3, 3,5-dichlorphenylisocyanate_CAS 28479-22-3, phenylisocyanate_CAS 103-71-9, trifluormethoxyphenylisocyanate_CAS 35037-73-1) which all have strong skin sensitisation properties, monoisocyanates without reliable studies will be additionally classifified with R43.

According RL 1272/2008/EG (GHS) a classification as Skin Sens.1A (H 317: May cause an allergic skin reaction) is warranted, based on comparative analysis regarding other isocyanates isocyanates (p-isopropylphenylisocyanate_CAS 31027-31-3, n-butylisocyanante_CAS 111-36-4, 3,4-dichlorphenylisocyanante_CAS 102-36-3, 3,5-dichlorphenylisocyanate_CAS 28479-22-3, phenylisocyanate_CAS 103-71-9, trifluormethoxyphenylisocyanate_CAS 35037-73-1 are all strong sensitisers, classified as Skin Sens. 1A). No classification for respiratory sensitisation is necessary (see discussion below).

There are no data on respiratory sensitization available. p-tolyl isocyanate is a monoisocyanate. The UK Health and Safety Commission Working Group on the Assessment of Toxic Chemicals, Working Group on Action to Control Chemicals concluded performed an assessment of the potential for isocyanic acid and other monoisocyanates to cause respiratory irritation and sensitization (WATCH Committee Paper WATCH/2008/4, 17 Jun., 2008; http://www.hse.gov.uk/aboutus/meetings/iacs/acts/watch/170608/p4.pdf) and came to the following conclusion: “With the exception of methyl isocyanate, information on the toxicity of the monoisocyanates is sparse. There is no direct evidence that any of the monoisocyanates can cause respiratory sensitisation. … However, this indirect information on the allergenicity and immunoreactivity of the monoisocyanates is very limited, and insufficient to reliably inform on their potential to cause respiratory sensitisation.” A similar conclusion was drawn by the German MAK commission concerning the monoisocyanates in 2009 (MAK- und BAT-Werteliste 2009).

 

In addition it should be also mentioned that the ‘default’ assumption of the former EU hazard classification systems that all isocyanates have the potential to cause respiratory sensitisation is not in agreement with the strategy for evaluating respiratory sensitisation data in the Technical Guidance Document (TGD) on information requirements for REACH (R.7a; page 256ff). The TGD proposes that, in the absence of specific health effects data, only diisocyanates that also meet the criteria for classification for skin sensitisation are presumed to be respiratory sensitisers.

Justification for classification or non-classification

Due to regulation 67/548/EEC isocyanates have to be classified as respiratory sensitisers with R 42. Based on comparative analysis regarding studies on skin sensitisation with other isocyanates (p-isopropylphenylisocyanate_CAS 31027-31-3, n-butylisocyanante_CAS 111-36-4, 3,4-dichlorphenylisocyanante_CAS 102-36-3, 3,5-dichlorphenylisocyanate_CAS 28479-22-3, phenylisocyanate_CAS 103-71-9, trifluormethoxyphenylisocyanate_CAS 35037-73-1) which all have strong skin sensitisation properties, monoisocyanates without reliable studies will be additionally classifified with R43.

According RL 1272/2008/EG (GHS) a classification as Skin Sens.1A (H 317: May cause an allergic skin reaction) is warranted, based on comparative analysis regarding other isocyanates isocyanates (p-isopropylphenylisocyanate_CAS 31027-31-3, n-butylisocyanante_CAS 111-36-4, 3,4-dichlorphenylisocyanante_CAS 102-36-3, 3,5-dichlorphenylisocyanate_CAS 28479-22-3, phenylisocyanate_CAS 103-71-9, trifluormethoxyphenylisocyanate_CAS 35037-73-1 are all strong sensitisers, classified as Skin Sens. 1A). No classification for respiratory sensitisation is necessary (see discussion).