They are not surplus, but rather manufactured for the civilian market. The US has also adopted the sceptre system.
Here is a link to the fuel can page for Sceptre:
http://mil.sceptermilitary.com/fuel_...uel_canisters/
And from there, here is a link to some of the civilian distributors of these products:
http://mil.sceptermilitary.com/military_distributors/