BACKGROUND: Information on the occurrence of contact allergens and irritants is crucial for the diagnosis of occupational contact dermatitis. Material Safety Data Sheets (MSDS) are important sources of information concerning exposures in the workplace.

OBJECTIVE: From a medical viewpoint, to evaluate the information available from MSDSs, and to ascertain whether MSDS are easy to obtain, whether they serve their purpose, and whether they provide sufficient information regarding allergens to enable correct diagnosis.

METHODS: MSDS and ingredients labelling were collected from consecutive patients and reviewed. If it was suspected that the MSDS were incomplete, the manufacturer, supplier, salesperson or workplace was contacted to gather more information.

RESULTS: Twenty-five per cent (79/316) of patients provided material for the exposure assessment. One or more shortcomings were found in 18.6% (137/738) of the MSDS. The most frequent shortcoming was 'Missing R43/H317 while known contact allergen was present', which was observed in 63.1% (84/137). Other shortcomings were 'Names of preservatives not included in section 3 despite containing preservatives', in 48.9% (67/137), and 'Nothing about allergy in sections 2, 3, 11, 15 or 16 in the MSDS despite the content of allergens', in 20.4% (28/137). The information retrieved led to additional testing of 21 patients.

CONCLUSION: Systematic exposure assessment is time-consuming. The main shortcomings are errors/omissions in the MSDS.