Leak protection system on a tank for storing or transporting liquefied gas

A leak protection system for a tank for storing or transporting liquified gas which comprises, the combination of, means for collecting the liquified gas which leaks from the tank, a catch basin positioned beneath the tank and of sufficiently large dimensions to permit gradual evaporation of the leaked material, said catch basin comprising an upper section and a lower section and positioned whereby said collection means discharges the liquified gas into said upper section, a plurality of ducts extending from the bottom of said upper section to above said lower section and providing flow paths for the liquified gas from said upper section to said lower section, each of said ducts extending between locations at said upper and lower sections which are diametrically opposite with respect to the vertical center axis of said catch basin, said upper section being in the shape of a cross and subdivided by means of partitions which are lower than said outer walls and form a central cell and a cell in each arm of the cross, and wherein a duct extends downwardly from each arm of the cross and opens out above said lower section of the basin.