The oilrig burned for two days straight, a fireball that could be seen from shore, before the massive six-story tall platform sank into the oceans depths. Eleven workers lost their lives, families grieved, and nearly 200 million gallons of oil surged from the seafloor, spreading an oil slick the size of Connecticut across the surface of the Gulf. On top of that, another 2 million gallons of a toxic dispersant was added to hide the oil slick at the surface, causing oil droplets to form and sink into the depths. It was a catastrophe of epic proportions and the largest oil spill in United States history.

To me, the haunting image is of a submersible robot, deployed 5,000 feet deep, extending a metal claw and trying to activate a shut-off device to stop the flow of oil. Following the explosion, the Deepwater Horizon began gushing over two million gallons of oil every day. The robot, a sophisticated, high-tech, somewhat brilliant invention, at one time the talk and hope of some Board room meeting, kept failing, as have so many of our plans which don’t take into account the consequences of our actions and the fragility of the natural system. The image of this ineffective metal claw became, to me, the symbol of our technological hubris and misguided energy policy. After three months of oil pouring into the Gulf of Mexico, the well was finally closed. The oil stopped spewing, but the impact was just beginning.

Thirty days after the explosion, the winds and currents that move our oceans deposited the Deepwater Horizon’s oil from the open sea to the precious salt marshes and coastlines of Louisiana, Mississippi, Texas, Alabama, and Florida, coating over 1,000 miles of shoreline. A region that produces 80% of U.S. oysters, 69% of shrimp, and 26% of the nations blue crab was suddenly met with a flood of oil. Fisheries closed, tourism and recreation halted, and people desperately wondered, what would happen next?

In 2010, shortly after the spill, my team and I traveled to the Gulf of Mexico to witness first hand the consequences of the country’s largest environmental disaster. We met with scientists, spoke to fishermen, and engaged with residents living along the Gulf coast, as they voiced their fears for the uncertainties that lie ahead – what will happen to the marine species inhabiting the Gulf of Mexico? What are the economic consequences to the region? And what is the future of human health for those living near this catastrophe and for those trying to clean up this environmental calamity?

In the five-year aftermath, many of these questions remain unanswered.

The Deepwater Horizon Oil Spill was an unprecedented disaster in US history. Not only was it the most massive in terms of volume of oil spilled, but also it was the largest use of a toxic dispersant, Corexit, in the natural environment. Numerous studies conducted by researchers in the region found the dispersant to be toxic to phytoplankton and other species living in the Gulf, with one study suggesting that the mixture of oil and Corexit together creates conditions that are 52 times more toxic than either alone. Even after five years of research by federal and private industries, we still do not know the long-term consequences regarding how long the oil and dispersant will continue to exist in the gulf, how long it will travel through the food web, and ultimately, the impact it will have on humans when they consume species who have accumulated these chemicals.

The area of the oil spill spanned the ranges and habitats of over 8,000 species, including fish, birds, mollusks, crustaceans, sea turtles and marine mammals. Thousands of birds, sea turtles and dolphins washed ashore in the months following the spill, shrimps were found without eyes, crabs without claws, and fish with lesions and tumors across their bodies, among other mutations. It took over eight months for the oyster fishery to reopen, only after continuous testing that deemed the mollusks safe for human consumption by the federal government, and the better part of a year for shrimp fisheries to reopen. This past year, shrimp catches in the western Gulf fell below long-term averages and smaller oysters were harvested this year than previous averages.

The fate of marine mammals, particularly bottlenose dolphins in the Gulf, continues to remains bleak. In the longest dolphin die-off in Gulf history, the number of dolphins washing up on Gulf beaches has been 8 times higher than the historical average in Louisiana, and 4 and 5 times higher in Alabama and Mississippi, respectively. A recent study found convincing evidence linking dolphin deaths to the oil spill. Researchers studying dolphins in Barataria Bay, Louisiana found dolphins 5 times more likely to have moderate to severe lung disease, consistent with exposure to petroleum hydrocarbons from the spill. They are also finding dolphins in the region with poor immune systems and high susceptibility to diseases, as well as hormonal abnormalities likely contributing to reproductive problems that could influence the future dolphin generations to come.

More than two decades after the devastating 1989 Exxon Valdez oil spill, orca populations in Prince William Sound that had the unlucky fate of coming in contact with the spill continue to feel its effects. Following the spill, two separate orca populations came in contact with oil, and both groups saw an unprecedented number of orcas deaths. Twenty years later, both populations of orcas continue to remain below pre-spill numbers, and since the spill, one of the populations has not seen a single baby orca born. During the Deepwater Horizon spill, I witnessed newborn bottlenose dolphins coming to the surface to breathe, and nurse with their mothers, all in the midst of the greatest oil spill in history. I only hope they do not face the same fate.

The mixture of oil and the dispersants in the Gulf were studied by federal scientists and found to cause heart abnormalities and cardiac arrest in fish, including the highly depleted Western Atlantic Bluefin tuna. A species that has already been decimated and overfished by 82 percent of it’s historic population in the last forty years, the Deepwater Horizon oil spill coincided with the tuna’s breeding grounds and peak spawning time. Larvae are especially vulnerable to toxins as they develop, and as tuna are a slow growing species that matures later in life, it will take generations to fully understand the effects the oil had on these populations. During the tragic Exxon Valdez Spill in 1989, which I also witnessed first-hand, the Pacific herring population in the region completely crashed four years after the spill – testament to the unknown environmental consequences caused by human negligence. In perspective, the Exxon Valdez was 5,000 times smaller than the Deepwater Horizon oil spill.

Those whose livelihoods depended on a healthy marine ecosystem in the Gulf, particularly the fishing and tourism industries like recreational fishing, excursions trips, and seafood restaurants, were all left at a complete economic loss. Many sold or lost their businesses, and have yet to see any reimbursement from the oil company, BP, who operated the Deepwater Horizon during the catastrophic spill. Contrary to what BP is advertising – that the Gulf is back to base-line levels and no longer influenced by the spill – residents continue to find tar balls on the beaches, oil buried in sediments, and dwindling wildlife five years later.

In Louisiana alone, 4.6 million pounds of oil were removed from beaches and coastlines in 2013, double the amount that was removed in 2012. The oil undoubtedly remains in the Gulf. After the explosion in 2010, clean up crews began immediately trying to contain and systematically remove oil, using methods such as corralling oil and then conducting “controlled” burns, which incidentally caused the deaths of an estimated 400 endangered sea turtles in the Gulf, who were trapped in corrals and unable to escape. A federal report determined in 2010 that 25 percent of oil was removed by burning and direct skimming methods, while the residual 75 percent continued to persist in the environment.

Where did the rest of the oil go? While some of the oil evaporated or degraded naturally, researchers have recently discovered massive tar mats along the seafloor. As oil and dispersants accumulated following the spill, they interacted with phytoplankton and other organisms, causing them to clump together and sink to the seafloor. Now, an estimated 25,000-pound tar mat lies at the ocean bottom off the Louisiana coast. Impacting deep-sea corals and other bottom-dwelling species, the tar will continue to persist in the deep, cold ocean, overturning and releasing into the water column during intense weather conditions or high wave activity.

While the serious impacts to natural ecosystems from the oil spill have been immense, the effects of the oil spill and chemical dispersant on human health has been critically overlooked and under recognized by the media and government. In the years following the spill, an estimated 170,000 people worked in some capacity to clean the oiled and tarred coastlines. The most common medical reports from workers were headaches, shortness of breath, skin rashes and chronic coughs. A recent study reported in the American Journal of Medicine found that people who worked on the spill had significantly altered blood profiles that put them at an increased risk of developing liver cancer, leukemia and other disorders. Since no research was conducted on these patients before the spill, this information cannot conclusively say that the oil spill is to blame. However, BP and other agencies knowingly put clean up crew workers in danger. Although many workers were advised to wear rubber shoes, wear oil-resistant gloves, and wear equipment to avoid breathing toxic gasses, many still developed health problems. These local residents were working to clean up their homes and their livelihoods, caring for an environment they did not carelessly damage, and paying with their health. It will take many more years to fully understand the health consequences imposed on the Gulf’s devoted caretakers.

Five years ago, when we explored the state of the Gulf and immediately realized the magnitude of this environmental disaster, we hoped this would become the country’s wake-up call. How many human lives are worth the price of oil? How much ecological degradation can our planet withstand before it can no longer support our food and resource needs? If we do not reduce the amount of deep-sea offshore oil drilling now, what will happen to the livelihoods, economies, and ecosystems that sustain us when the next oil spill happens?

As we reflect on the past, it is time to be more proactive and think of what environmental legacy we are leaving for future generations. We need to continue to search for more sustainable, renewable resources, knowing our every day lifestyle choices could keep us drilling deep into sensitive marine environments with disastrous consequences. Instead, we could wean ourselves off these non-renewable energy sources and tap into the free services of Mother Nature, extracting energy from the wind, the sun, and the tides.

There are already innovative businesses harnessing these renewable and carbon free energies, the only thing left is for us is to choose to support them. After five years of research, learning, and ultimately realizing there is still an enormous amount we do not know about the long-term consequences of the largest oil spill in history, let this tragedy be a reminder of our planet’s fragility and a warning about the disastrous consequences of running our societies on unsustainable energy. Oil spills continue to happen every day around the world, in the oceans, our land, even in our backyards. If we continue to allow oil companies to dig deeper and further for more nonrenewable fossil fuels, colossal oil spills will undoubtedly follow. As caretakers of our planet, we have the responsibility and now the knowledge to move towards a cleaner future and leave behind a legacy we can be proud of.