The OESs are specified in a list approved by the Health and Safety Commission. Absorption through the skin can result from localised contamination, for example from a splash on the skin or clothing, or in certain cases from exposure to high atmospheric concentrations of vapour. Serious effects can result with little or no warning and it is necessary to take special precautions to prevent skin contact when handling these substances. Where the properties of the substances and the methods of use provide a potential exposure route via skin absorption, then these factors should be taken into account in determining the adequacy of the control measures. Sensitisation Certain substances may cause sensitisation of the respiratory tract if inhaled, or of the skin if contact occurs.
Respiratory sensitisers can cause asthma, rhinitis, or extrinsic allergic alveolitis.
Skin sensitisers cause allergic contact dermatitis. Substances which cause skin sensitisation are not necessarily respiratory sensitisers or vice-versa. Only a proportion of the exposed population will become sensitised, and those who do could not have been identified in advance. Individuals who have become sensitised may produce symptoms of ill-health after exposure even to minute concentrations of the sensitiser. Wherever it is reasonably practicable exposure to sensitisers should be prevented.