As of April 2022[update], SOLAS 1974 has 167 contracting states,[1] which flag about 99% of merchant ships around the world in terms of gross tonnage.
[1] SOLAS in its successive forms is generally regarded as the most important of all international treaties concerning the safety of merchant ships.
[2][3] The non-parties to SOLAS 1974 include numerous landlocked countries, as well as El Salvador, Micronesia and East Timor.
Some others including Bolivia, Lebanon and Sri Lanka, all considered flag of convenience states, are deemed to have "potentially negative performance" regarding ratification.
[6] The first version of SOLAS Treaty was passed in 1914 in response to the sinking of RMS Titanic, which prescribed numbers of lifeboats and other emergency equipment along with safety procedures, including continuous radio watches.
It represented a considerable step forward in modernizing regulations and keeping up with technical developments in the shipping industry.