Under European Union (EU) law, various heavy metals (both the metallic form and their compounds) are banned according to Regulation (EC) No. 1223/2009. We will discuss what heavy metals are, why they are not allowed in cosmetics and where traces of them may come from. Pursuant to Article 17 of Regulation (EC) No. 1223/2009, the non-intended presence of a small quantity of a prohibited substance, which is technically unavoidable in good manufacturing practice, is allowed as long as the product is safe for human health. A definition of “technically unavoidable” is unfortunately not provided in Regulation (EC) No. 1223/2009. For both manufacturers and Responsible Person, knowing what limits are currently considered as technically unavoidable is imperative. We will briefly cover the test methods used to detect heavy metals and then look at in detail what may be considered as a “technically unavoidable” level of heavy metal impurity in a finished cosmetic product. We will consider in detail orientation values for “technically unavoidable” heavy metal content We will also touch upon other impurities that may be found in cosmetic products and what maybe considered as a “technically unavoidable” level for these impurities. Finally, we will talk about what to do if you discover impurities (in particular heavy metal impurities) in your product – what can be done to reduce the impurities and methods for defending the presence of these impurities once all strategies to reduce the impurities have been exhausted.