(100)Public contracts should not be awarded to economic operators that have participated in a criminal organisation or have been found guilty of corruption, fraud to the detriment of the Union’s financial interests, terrorist offences, money laundering or terrorist financing. The non-payment of taxes or social security contributions should also lead to mandatory exclusion at the level of the Union. Member States should, however, be able to provide for a derogation from those mandatory exclusions in exceptional situations where overriding requirements in the general interest make a contract award indispensable. This might, for example, be the case where urgently needed vaccines or emergency equipment can only be purchased from an economic operator to whom one of the mandatory grounds for exclusion otherwise applies.