Organic chemicals from the Polish maximum allowable concentration (MAC) list were analyzed for skin notation. It can be concluded that the dermal dose LD50s determined on experimental animals ought to be adopted as the fundamental criterion for providing a substance with the percutaneous absorption notation in the MAC list. All chemicals with LD50s. value below 1,000 mg/kg should be provided with the Sk index in the MAC list. For other chemicals, a skin notation would be considered when repeated human and dermal application tests have shown significant systemic effects following exposure. When information on the characteristics specified above were not available, physicochemical data required to calculate the flow (solubility, octanol/water partition coefficient, molecular weight) were obtained to consider a skin notation.