Member States are obliged to take the necessary measures to ensure that products are placed on the market and put into service only if they do not endanger the safety and health of persons, or other public interests covered by the directive, when properly installed, maintained and used for the intended purposes. This entails an obligation for market surveillance on the part of the Member States.

Member States are allowed to adopt, in compliance with the Treaty (in particular Articles 28 and 30 of the EC Treaty), additional national provisions to protect, in particular, workers, consumers or the environment. However, these provisions may neither require modifications of the product nor influence the conditions for its placing on the market.