it should be filled with sand or absorbent materials and capped, so that a sink hole is not formed, and no fuel trace is left behind.Thus any fuel residue does not sweep into a ground water source and contaminate it.
Typically the EPA requires the pit or hole to be filled with sand or other type of absorbent material and capped off this will prevent a sink hole from forming while also allowing for the prevention of any fuel residue left over from seeping into the ground water supply and affecting surrounding areas.
