On April 20, 2010, the Deepwater Horizon drilling rig exploded in the Gulf of Mexico, causing the worst environmental disaster in the United States to date. Five years later, lumps of tar are still lying on the coast – and the extent of the disaster remains unclear.

John Lopez steers his boat out of the small harbor of Pointe à la Hache into a narrow channel. On the banks, green mud grass sways in the wind, crabs dig in the muddy bottom, and birds dive into the water in search of fish.After about a kilometer, the stocky man with the black and gray beard stops the boat and climbs onto the bank. Coastal researcher John Lopez works for the environmental organization Lake Pontchatrain Basin Foundation, and often travels out into the coastal marshes south of New Orleans.Lopez spreads out a map on which a network of small and tiny waterways runs through a network of small islands: the Mississippi Delta, on the coast of Louisiana.”We are roughly here now. This marshland was oiled back then, although not as severely as other areas.”Around 800 million liters of oil spilled into the Gulf of Mexico in the spring and summer of 2010, following the explosion of the Deepwater Horizon oil platform. It was the largest oil spill in history.

“ The oil has killed many plants directly and caused long-term damage to wetlands, as well as to oysters, crabs, fish, crayfish, shrimp and other animals.”The small island where John Lopez is now searching for traces of oil is in Plaquemines Parish. This parish has suffered more than any other from the consequences of the oil spill, reports Billy Nungesser. The Republican was mayor of Plaquemines Parish for many years.

“ According to BP and Coast Guard figures, our community alone received 33 percent of the oil that washed up on the entire Gulf Coast.”

The oil disaster hit people on the coast twice as hard
The oil killed hundreds of thousands of birds and fish, hundreds of marine mammals, countless crabs, shrimps, insects and small creatures. Fishing had to be stopped in large parts of the Gulf of Mexico in the summer of 2010. The oil disaster hit people on the coast twice as hard.

“Many families here in Plaquemines Parish have some family members working in fishing and others in the oil industry. When the moratorium was put in place after the oil spill and no one was allowed to work on the oil rigs, but at the same time no one could fish anymore, it was very hard on the community. People just didn’t know how they were going to make a living and what would happen in the long term.”And then BP got involved and spread even more fear and uncertainty.

“ I was very upset at the time. You could see it every night on TV. BP kept putting new obstacles in our way. When the first pictures of oiled birds were shown on TV, we thought we would get help to save these birds. And people came from all over the world to help. But BP and the coast guard said that anyone who even came near the barriers would end up in jail. We were supposedly disrupting the clean-up work. We all know that was an absolute lie. They just wanted to intimidate the helpers to prevent more pictures of oiled birds on TV.”All of this put a lot of strain on people, says Billy Nungesser. Dale Sandler also has this impression. The doctor from the US National Institute of Environmental Medicine is currently conducting a large-scale study into the consequences of the oil spill for the health of people on the coast. She is particularly interested in the workers who helped clean the beaches and coasts of oil. Dale Sandler and her team surveyed 32,000 people about their tasks during the oil spill, their employment situation and their health – immediately after the oil spill and then repeatedly in the years that followed.

“ Our data suggest that those involved in the cleanup and those living on the affected coasts complained more frequently of a whole range of symptoms, such as coughing, wheezing, dizziness and nausea. And this continued for years. But we do not yet know whether these symptoms were caused by the oil itself, by the living conditions in the communities or by the traumatic experience of the oil spill.”Most of the workers came from communities on the north coast of the Gulf of Mexico, which suffer from high unemployment and poor health care. Here, three of the poorest states in the USA border the ocean.

“ We know from previous oil spills and from ongoing studies in the affected communities that anxiety and depression often increase after oil spills and there are signs of post-traumatic stress disorder. Experiencing the oil spill first hand and battling the oil on the beaches – all of this is very stressful. As is losing your job and not knowing what will happen next, if and when you will be able to fish again and how you will support yourself. All of these aspects could explain the depression that we are diagnosing.”Dale Sandler’s results are still fragmentary. Some of the cleanup workers are refusing to work with her. They are currently suing BP for damages and their lawyers fear that the doctors could diagnose chronic illnesses that have nothing to do with the oil. This would seriously weaken their chances of winning the lawsuit.

As if the oil disaster had never happened

“ I was at home and watched the news about the fire on TV. At first I was just interested and didn’t think that it could get out of control, that we would get this catastrophic oil spill. We kept watching TV over the next few days and slowly the horror began to rise in us as we realized what was going on in the deep sea and that the problem might not be brought under control.”About 200 kilometers east of the Mississippi Delta, the sun is reflected on the water that laps gently onto the beach at Pascagoula. Birds fly up and follow a passing fishing boat. A few meters away, anglers have set up their folding chairs and cast their rods. Everything here looks as if the oil disaster had never happened. John Marquez is standing on a jetty a little way off and watching the goings-on. The tall man in the white shirt is the chairman of the Coastal Conservation Association in Mississippi, an association of sport fishermen.

“ Immediately after the oil spill, we had some very good fishing years. Its hard to say why. Fishing had been completely shut down in 2010, so there was no hunting pressure on the populations. We thought that might be why there were more fish in the following years.”Almost 2,000 kilometers of coastline were smeared with oil in the summer of 2010. An oil slick one and a half times the size of Saarland drifted on the ocean for months. And then the oil disappeared almost completely from the scene within a very short time, remembers John Marquez.

“ But last year was one of the worst years for spotted sea trout and the worst year for crab in nearly 50 years. Now we are very worried. Are these the consequences of the oil spill that are only now emerging? We are monitoring the environment very closely and hope that it is just a coincidence, or a seasonal phenomenon and not something much more catastrophic that comes from the oil spill.”Oil spills can have long-term consequences. For example, in Alaska, a few years after the Exxon Valdez oil spill in 1989, herring stocks collapsed out of the blue. They have not recovered to this day. Many people fear the same in the Gulf of Mexico. Here, for example, bluefin tuna is of enormous importance to the region’s fishermen. John Marquez is not the only one worried about it.

“ The Deepwater Horizon oil platform exploded just at the beginning of the bluefin tuna breeding season in the northern Gulf of Mexico.”Ryan Fikes works as a biologist for the environmental organization National Wildlife Federation in Corpus Christi, Texas.

“ The spawning areas were partially covered in oil, so the larvae there most likely came into contact with polycyclic aromatic hydrocarbons and other toxic compounds. Estimates of how many tuna larvae were exposed to the oil vary between 12 and 20 percent. At the same time, laboratory studies have shown that components of the oil attack the heart cells of young bluefin tuna and can cause irregular heartbeats and heart attacks. This could mean that fewer young fish survive and that the number of adult animals will therefore decrease in the coming years.”Bluefin tuna are already on the Red List of endangered species. If more of them disappear, the survival of this species could become critical. However, it is not yet known how many larvae and fish were killed by the oil from the Deepwater Horizon. The same applies to many other animal species. Since the oil spill, for example, dead dolphins have repeatedly been stranded on the coasts of the Gulf of Mexico – and in fact far more than in the years before the oil spill.

The beaches are white again
But hardly anyone knows how the deaths are affecting the population. These questions are being investigated, but the answers are still being kept secret, says Ryan Fikes. They are to be used as evidence in court.”One of these studies is NRDA, or the Natural Resource Damage Assessment. This is a process in which US federal authorities collect investigations, studies, and other evidence for a later federal court case against those responsible for the oil spill. In the view of the US government, publishing the results of these investigations now could influence the outcome of the court case and jeopardize a conviction. Because the perpetrators are of course working on their defense with their own scientists and their own assessments in order to refute the prosecutors’ arguments.”The NRDA process will also examine possible long-term effects of the disaster. It will therefore be some time before the study results can be used in court and then published.

“ We can of course sit down and say that this research is being carried out on behalf of the federal government, so its results should also be publicly available. But at the same time, I understand how important it is to handle this information sensitively to ensure that those responsible can be held accountable.” Another civil case has been underway in the Federal District Court in New Orleans since February 2013. The issue is who is to blame for the accident and how much damage was caused, i.e. how much oil was spilled. Legal experts describe the case as the most complex legal proceedings in modern history. The United States of America and numerous private individuals are suing BP, Transocean, Haliburton and other companies involved in the oil spill for more than 14 billion US dollars in damages. A verdict is not expected until May 2015 at the earliest. But it is already clear that a lot of money will flow into the region, says the former mayor of Plaquemines Parish, Billy Nungesser. “ And since we’re talking about a lot of money, there will be a lot of people who want to spend it. I hope and pray that the money will go where the oil has really caused damage. We need it to rebuild the coast and to help the animals and plants. But there are also people who are attracted by all that money and have interests other than doing the right thing. We can only hope that doesn’t happen.”Billy Nungesser was the head of the community from 2007 until the end of 2014.

“ During the last years of my term, we negotiated a lot with the people from BP in the hope of reaching an agreement on a sensible use of the money. Unfortunately, that didn’t work out. My term ended without an agreement being reached. I think that had a lot to do with the lawyers. They often don’t benefit from sitting down together and working on a solution.”On the coasts of the Gulf of Mexico, there are hardly any signs of the consequences of the disaster today. The beaches are white again, the coastal marshes sway in green mud grass, and only traces of the oil are still deep in the ground. The situation is different in the deep sea.

“ When we first went diving near the Macondo borehole, that was in December 2010 with the manned underwater vehicle Alvin, we were stunned. There was nothing down there, no life. Normally, worms live on the sea floor, shrimps, crabs and fish live there. Maybe not many fish, but on every dive you see at least one fish, you find sea cucumbers and every now and then a big squid or an eel swims by, there are a whole range of different fish species. But we saw absolutely nothing during this dive.”Instead, oceanographer Samantha Joye from the University of Georgia found mud, and lots of it. In some places, it was piled up ten meters high and suffocated all life beneath it.

The corals are getting worse every year since the oil spill“Many people did not expect the impact on the deep sea. About 30 percent of the oil from the well and all the gas that leaked out never reached the sea surface. Instead, the oil wafted through the deep sea in huge plumes. Some of it was broken down by microorganisms, some was so diluted that we can no longer detect it. But the third part rained down to the sea floor and settled there. I don’t think anyone predicted how enormous the quantities would be. Today you can take sediment samples within a radius of almost 100 kilometers around the well and you still find traces of the Macondo oil.”Oil is actually lighter than water and should rise to the surface. That’s why it’s not yet entirely clear where the huge amounts of oily mud on the sea floor come from. Samantha Joye suspects that the smallest plants in the sea, phytoplankton, and the microorganisms that break down the oil are responsible. If they come into contact with oil, both release substances that are slimy and sticky and easily adhere to the oil. Heavy oily clumps could subsequently sink to the sea floor as particle rain.

“ The ecosystems on the sea floor suffered greatly from this oily sea snow and they are still suffering today. I am often asked how long it will take the deep sea to recover from this. It is cold down there, everything grows more slowly and nothing happens quickly. So the ecosystems will probably take much longer to recover than a beach or a coastal marsh, for example. Because up there it is very, very warm in summer and in winter it does not get as cold as in the deep sea.”And there is something else that worries Samantha Joye. There are large coral banks on the sea floor of the Gulf of Mexico: an important habitat for many species of fish. But these corals have been getting worse year after year since the oil spill.

“ The corals are still in decline today, they have not yet reached the point where we have seen all the effects and they are starting to recover.”It is possible that the oily mud on the sea floor will be stirred up and put pressure on the corals again and again. That would be a bad sign, and not just for the corals. When the mud is pushed back into the water column by storms or currents, it can also find its way back into the food web and cause long-term damage to life in the deep sea. It will take years, if not decades, to assess the full extent of the oil disaster of April 20, 2010.