Styrene

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Additional information:

In the UK RAR (June 2008) the data on sensitization were summarized as follows (the references are given in brackets):

 

The reporting of the available animal skin sensitization data is inadequate, precluding a clear conclusion being drawn from the studies themselves (Sjöborg et al., 1982). However, given that widespread exposure to styrene has led to only one reported possible case of skin sensitization (Sjöborg et al., 1982), this extensive human experience indicates that styrene is not a significant skin sensitizer and negates the need for any further animal testing with respect to this endpoint. A literature search from 1998 to January 2010 overlapping the date of the UK RAR (June 2008) was conducted. Overall, this did not lead to a modification of the conclusions reached by the UK RAR and reinforced some of the aspects elaborated above.

Migrated from Short description of key information:
WoE: not skin sensitizing

Respiratory sensitisation

Endpoint conclusion

Additional information:

There has been extensive inhalation exposure in humans which has resulted in only two case reports of asthma (Hayes et al., 1991; Moscato et al., 1990), each of which has unconvincing aspects to it. This suggests that styrene has no significant asthmagenic potential.

 

Already in 1987 Moscato et al., (1987) described two cases of occupational asthma due to styrene exposure.

 

Volkman et al. (2006) described a case of hypersensitive pneumonitis of a worker at a yacht manufacturing company rolling fiberglass impregnated with resin. A bronchial challenge test with styrene was not carried out, but due to the chemicals handled at the workplace styrene was hypothesized as a possible causative chemical.

 

In a letter to the editor Fernandez-Nieto et al. (2006) described a worker in an auto body shop with asthma that was assigned to styrene by a specific inhalation challenge test with styrene.

Öner et al. (2002) studied 47 subjects occupationally exposed to styrene working with polyester resins. Each worker underwent a clinical interview, pulmonary function testing and bronchial challenge with metacholine. For those with an indication of asthma, specific bronchial challenges with styrene were carried out followed by serial peak expiratory flow measurements at home and at work over several days. Five workers gave a history of work related symptoms and 3 of them had a positive metacholine challenge test. All 3 responded negative to the specific challenge with styrene, but for one worker the serial peak expiratory flow measurements gave an indication for an asthmatic reaction. The authors interpreted their findings as suggestive but not conclusive for an asthmatic reaction due to styrene.

 

A literature search from 1998 to January 2010 overlapping the date of the UK RAR (June 2008) was conducted. Overall, this did not lead to a modification of the conclusions reached by the UK RAR and reinforced some of the aspects elaborated above.   

 

In summary, there are some further case reports of respiratory allergies related to styrene exposure. But taking into account the widespread use of styrene the conclusion of the UK RAR still has to be maintained that styrene has no significant asthmagenic potential.

Migrated from Short description of key information:
not respiratory sensitizing

Justification for classification or non-classification

Taken together the present data for the test substance do not fulfill the criteria laid down in 67/548/EEC and 1272/2008/EEC for skin and respiratory sensitization, respectively, and therefore, a non-classification is warranted.