Abstract Liquefied Natural - Petroleum Gas are usually stored by especially low temperature tanks, with different design configurations developed in the industry using steels with specified low temperature properties. This paper gives an overview on the properties, and behavior of the 9 %-Nickel-alloyed high strength steels for low temperature applications. These steels have been recognized by the ASME code for cryogenic use since 1954 and has been widely used for LNG storage in competition with stainless steel, other austenitic alloys and aluminum.in fact, austenitic stainless steels are used in cryogenic applications and can be used for building smaller storage tanks, but large containment vessels are usually welded from 9% nickel steel because of expense considerations. This technology is well-established worldwide. The first part of this paper is focused on the 9% nickel steel, its properties and, use in the LNG storage tanks. The different LNG tanks design generations, their particularities will be described. A general overview of LNG tanks failures recorded in the industry will be presented as well. Inspection, repair and alteration of atmospheric tanks designed according to API 650, are well covered with the API 653 standard, unlike the cryogenic tanks generally designed according to API 620 or BS 7777, no standard exists to cover the inspection, repair alteration requirements - when applicable - to recertify these tanks. The document provides a benchmarking of different cryogenic tanks in terms of operation life and type of containment (single, double containment tanks) in the LNG industry. Different options are addressed in order to recertify these tanks are adopted in the industry will be detailed. ADGAS operates three double walled tanks, reaching their design life. Longevity study was undertaken in order to re-certify the tanks based on different studies, inspection / operation / Maintenance history. Main outcomes of this study will be presented.