As it flooded, water would wash and lift oil from surfaces and float it to the roof of each storage level where it would collect.
(it; flooded; ) (water; would wash; T:As it flooded) (water; lift; oil; from surfaces) (it; would collect; L:each storage level)
it water water it
flooded would wash lift would collect
T:As it flooded
oil from surfaces
L:each storage level