Uneven implementation of Community law across the European Union is common practice. Differences in implementation of EU directives differences in degree of domestic adjustment are, according to variables identified in the Europeanization literature, to be explained by variations in the degree of fit and the availability of mediating factors. The analysis of the implementation of the Seveso II and Safety Data Sheets Directives in the Netherlands, Germany, the United Kingdom and Spain shows, however, that these identified factors alone do not suffice to explain the observed differences. This article pleas for a closer look at the role of 'issue salience' as a complementary factor that constraints or stimulates the existing mediating factors in the Europeanization literature.