"I don't think anybody on board really knew the full scope of what was going on,” says Lieutenant Steve Simmons.
What is clear is that within months of deploying to the coast of Japan following the accident, Navy Lt. Steve Simmons was getting sick. He was one of 70,000 United States servicemen and women who helped after the disaster.
Radiation poured in the air and water after a giant wave from a tsunami hit the power plant.
The aircraft carrier USS Ronald Reagan was one of the first ships on the scene to help.
Now about a hundred sailors from the ship have unexplained illnesses.
“One day I was just coming out of the bathroom and my legs just buckled on me and that was pretty much it,” Simmons says.
Now Simmons relies on a wheelchair. His lymph nodes are swollen.
Other Reagan sailors have reported leukemia and other cancers, along with bleeding, headaches and hair loss.
They are now suing the Tokyo Electric Power Company, Tepco, claiming it hid the dangers from the radiation leak at the Fukushima plant.
"The Tepco people who ran the plant never warned their government. Their government never warned the world. The command never got the order don't go you're going to get cooked,” says attorney Paul Garner.
Lawyers are facing an uphill battle – proving the link between the radiation leak and their illnesses.
“Drawing a cause and effect for individuals is exceedingly difficult,” says Professor Wayne Biddle of Johns Hopkins University.
Tests taken onboard the Reagan showed radiation levels below what is considered dangerous. Some of the sailors worry they may not live to see the outcome of their legal case.
“The hardest part is the family. We have three children. Our oldest daughter, she struggles with the dad’s going to die kind of thing,” Simmons says.
Simmons and his fellow sailors aren’t the only ones who want answers. Congress is now asking the Department of Defense for information about the medical conditions of crew members who were aboard the Reagan and what’s being done to treat them.