One year after Gulf spill, oil remains

>>> a year to the day after the deep water horison oil rig explosion fell into the waters of mexico, killing 11 workers, some of the survivors, family workers flew over that site today, and sin that day, grief has been mixed with anger over this disaster all along the gulf coast . our chief environmental affairs correspondent is with us tonight.

>> reporter: good evening, late today, bp filed suit against the maker of the blow-out preventers alleging a faulty design contributed to the oil spill . some of that oil is still in louisiana's marshes, and now officials here are trying to decide if the effort to clean it up is worth the risk to this fragile coastline. one year later, there are still clean-up workers in one of the most heavily oiled areas in louisiana' coast. using a giant hedge clipper , they cut a marsh to get at the oil trapped by the grasses. a giant rake gets the debris.

>> this is a little bit of resid ial left.

>> it has a sticky consistency.

>> it's kind of like a peanut butter consistency. if you try to get it all, you would really be potentially excavating the marsh and losing it.

>> reporter: 60 miles away , another area devastated by the spill, a path of blanks leads the way to the path of oil. the pungent odor of the summer is gone, but all it takes is a couple shovel fulls of muck and you can see the tell tale rust colored signs of oil.

>> the sheen on the surface.

>>> james peters who makes his living leading deep- sea fishing trips is seeing it, too.

>> you can see a sheen and oil droplets in the water.

>> there is no more visible oil on the island where we first saw the pictures. how healthy does cat island look to you?

>> frankly, it doesn't look too healthy.

>> he points to the dying man mangroves on the edge and the leafless interior. still, pelicans make their nest here. for all the effort of the past year, environmentalists say cleanup without coast restoration is pointless.

>> it's for naught because in five years all of that's going to be eroded away. in 50 years, it's all gone. everything you see is gone.

>> now, finally tonight, the government is strongly disputing an associated press report that says 3,200 wells in the gulf of mexico do not have cement plug and threaten to leak oil into the waters. the government said those are sealed and they're monitored every six month.