Today is day 100 of the BP oil spill and still no end in sight.

100 days ago the oil spill was a large plume of toxins polluting the gulf. Now, it's separated across a wider area of the gulf. "We're seeing less and less oil. And the oil we do see, it's weathered, it's sheen and sometimes it's not that effective to skim it," says National Incident Commander Admiral Thad Allen.

He says scientists are aggressively testing the water column for hydrocarbons. Even though the well head is stable, response teams are still on standby. "I still have over 811 skimmers, numerous vessels of opportunity, 11 million feet of boom," says U.S. Coast Guard Rear Admiral Paul Zukunft.

Zukunft says there have been a lot of lessons learned for the next 100 days and the future. "We reached out and have received assistance from over 22 foreign nations. So what we've recognized is the coast guard can't do this alone." He says if another oil spill of this magnitude happens, the response must be more than the federal government. It requires private industry, local and international participation.

Next week, workers will begin a static kill procedure to make way for the relief well. Allen says, "Obviously the depth is a challenge here but we are optimistic we will get this thing done."

The Coast Guard says you should still expect tar balls. Yesterday Saint Bernard parish reported a stretch of tar balls three miles long.