While these oil spills may be the most publicized (the Exxon Valdez for example), accidental spills from tankers account for only about 20% of the crude oil discharged into the world's oceans each year.
(these oil spills; may be; the most publicized (the Exxon Valdez for example) (accidental spills from tankers; account; for only about 20% of the crude oil discharged into the world's oceans each year)
these oil spills accidental spills from tankers
may be account
the most publicized (the Exxon Valdez for example
for only about 20% of the crude oil discharged into the world's oceans each year