In the 17th century, the doctrine of “mare liberum”, introduced by the Dutch jurist Hugo Grotius, formed the basis of the classical international law of the sea. The doctrine claimed that all states are free to use the seas to develop trade, which fitted the Dutch trading policy at that time. Soon it became clear that this doctrine did not have an absolute character and that new legislation should regulate the various uses of the sea.After the Second World War, international trade, offshore exploitation and therewith the risk to pollute the marine environment increased dramatically. Not only the carriage of oil increased but also the carriage of other hazardous and noxious substances expanded tremendously during the early 1970s. Therefore states developed a range of measures to prevent such marine pollution accidents. Together with this, the international community thought of establishing also repressive measures, such as liability systems. Namely, the potential establishment of an international oil pollution liability regime within the IMO framework received much attention. At the contrary however, the establishment of a civil liability regime for pollution by hazardous and noxious substances other than oil caused by tankers was not considered to be urgently necessary. Several major chemical spills however ignited the idea that a new liability regime should be established in order to cover third parties for the severe damage that often results from marine chemical accidents. It was not until the mid-1990s that states, operating under the International Maritime Organization (hereinafter IMO), managed to adopt an Hazardous and Noxious Substances Convention regulating the liability for accidents caused by hazardous and noxious substances. Since its adoption though, many obstacles encountered the ratification of the 1996 HNS. Therefore, the Conference of State Parties adopted a Protocol in order to facilitate the entry into force of the Convention. Whether this Protocol overcomes the various barriers present for the ratification of the Convention is still obscure and needs further research. This thesis will therefore focus on the following research question: “To what extent does the 2010 Protocol to the 1996 Convention strengthens the existing legal framework concerning the liability of marine casualties involving hazardous and noxious substances?”.