Maybe your local Fire Marshal could provide suggestions, as could a
local contractor specializing in storage for institutions that might
store a few hundred gallons.

It seems desirable to isolate the fuel from heat of fire (underground)
and with safe venting to prevent pressure buildup. Then a hand-pump
would transfer to containers. I've seen such a package installed to
Fire Marshal's satisfaction in CT. The tank had to be coated to his
satisfaction, inside & out, and he wanted to see about a foot of
round-sand next to the tank- even had it partly dug out after the fact
to be certain.

With kerosene, he had no problem with storage in barrels above ground.
Looks like diesel it is, on first-cost basis alone, for many.

J