Gulf Oil Spill -- BP's "Macondo Spill" -- Four Years On

Photos: A grim photographic tribute to the Deepwater Horizon disaster. John Metcalfe in The Atlantic Cities.

One former federal official says we're on course to repeat the mistakes of the past. "The United States is 'on a course to repeat' the same mistakes that led to the devastating Deepwater Horizon disaster four years ago, a former top offshore drilling regulator warned Thursday." Jennifer A. Dlouhy in the Houston Chronicle.

Long read: Scientists are still trying to understand the spill's environmental impacts. "Scientists are still struggling to understand how the oil and the dispersant chemicals used to break it down into tiny droplets have affected the environment of the deepwater Gulf of Mexico and the Louisiana shoreline and wetlands where a large amount of oil was deposited. 'In many regards, we were fortunate,' said Oregon State University marine biologist Jane Lubchenco, director of the National Oceanic and Atmospheric Administration at the time of the spill....'The caution is that we still don't fully know the true nature, the true extent of the damage, which is why it's so important that the ongoing damage assessment efforts continue.'" Mark Schleifstein in The Times-Picayune.

Explainer: Clarifying myths and misconceptions about the Gulf oil spill. "Does oil stick around in the ecosystem indefinitely? What was the deal with the deformed fish? Can anything bad that happens in the Gulf be blamed on oil?" Hannah Waters in Smithsonian Magazine.

But BP is refusing to pay for some Gulf spill impact studies. "BP is refusing to pay a large bill for US government-led studies into its 2010 oil spill in the Gulf of Mexico, including research into its impact on dolphins, whales and oysters. Documents seen by the Financial Times show that the US government last year requested $148m from BP to fund studies this year in to the effect of the spill. But the company refused to pay for most of them arguing that it should not be forced to finance studies that it is not allowed to see. The disagreement shows how the arguments over the clean-up of the gulf are emerging as a central issue in the multibillion-dollar legal actions still facing BP." Ed Crooks in The Financial Times.

And not everyone is happy with BP's payouts. "Four years after the Deepwater Horizon spill, oil is still washing up on the long sandy beaches of Grand Isle, Louisiana, and some islanders are fed up with hearing from BP that the crisis is over....The British oil major has paid out billions of dollars in compensation under a settlement experts say is unprecedented in its breadth. Some claimants are satisfied, but others are irate that BP is now challenging aspects of the settlement. Its portrayal of the aftermath of the well blowout and explosion of its drilling rig has also caused anger." Jemima Kelly in Reuters.

BP says 'active cleanup' complete? Try telling that to the Coast Guard. "The Coast Guard is crying foul at BP's statement this week that active cleanup efforts to remove oil along the Gulf Coast shorelines have ended. While BP claims it has reached a 'milestone' in the cleanup process, the Coast Guard says it's 'far from over.'" Collin Eaton in the Houston Chronicle.

The seafood industry remains chilled. Doug MacCash in The Times-Picayune.