4. Manufacturers shall ensure that procedures are in place for series production to remain in conformity. Changes in product design or in characteristics, as well as changes in the test methods by reference to which the conformity of a product is declared, shall be adequately taken into account.
When deemed appropriate with regard to the performance of, or the risks presented by, a detergent or surfactant, manufacturers shall carry out sample testing of such detergent or surfactant, investigate, and, if necessary, keep a register of complaints, of non-compliant detergents or surfactants and of recalls of such detergents or surfactants, and shall keep distributors informed of any such monitoring.