The first mention of the term "security" in an IMO treaty or Convention appeared after the hijacking of the Achille Lauro in 1985. The Assembly Resolution A.584(14) titled "Measures to Prevent Unlawful Acts Which Threaten the Safety of Ships and the Security of their Passengers and Crew" was adopted on November 20th that year.
The Maritime Safety Committee (MSC) of the IMO approved on September 26th 1986 the circular MSC/Circ.443, titled "Measures to to Prevent Unlawful Acts Which Threaten the Safety of Ships and the Security of their Passengers and Crew". This circular contained only recommendations.
Only three States have enacted national legislation incorporating recommendations contained in MSC/Circ.443 (USA, UK and Canada).
The next action taken by IMO regarding Maritime Security came in the form of the "Convention for the Suppression of Unlawful Acts Against the Safety of Maritime Convention (Rome 1988)", known as the SUA Convention.
On July 5th 1996, the Maritime Safety Committee adopted the circular MSC/Circ.754 titled "Passenger Ferry Security"