First ships crawl up Mississippi as cleanup of oil spill continues

Ships began crawling up the Mississippi River at New Orleans in a tightly controlled procession Friday, two days after a massive oil spill shut down a stretch of one of the nation's most critical commercial arteries.

The pecking order was based on Coast Guard determination of the economic importance of the ships' cargo, and the pace was slowed by a scrubbing process to remove oil from each hull. A ship carrying refinery-bound oil was the first to get the go-ahead.

With more than 200 ships waiting, it was expected to take days to clear the backlog that developed after the tanker Tintomara collided with a barge on Wednesday. About 419,000 gallons (1.6 million …