Five years after an exclusive 5 On Your Side investigation uncovered how thousands of navy veterans were secretly exposed to nuclear radiation, a government review board has officially linked exposure to cancer.

Thomas Wilborn served at McMurdo Station, Antarctica, where Navy serviceman lived, breathed and ate alongside what was then referred to as “a portable nuclear reactor."

But an exclusive 5 On Your Side Investigation in March 2011 revealed at least “438 malfunctions from 1964 through 1972."

Our report found “leaking water surrounding the reactor” as well as “hairline cracks in the reactor liner” and prompted two federal hearings that upheld our report’s findings.

The plant was eventually shut down and dismantled in 1972, but in the decades that followed, repeated cancer claims for service-connected disability filed by veterans were routinely turned down or ignored by the Veterans Administration.

“There is no question that the water was contaminated,” said Wilborn, who was granted a service-connected disability after a hearing before the Board of Veterans Appeals.

The appeals board also found that Wilborn’ s exposure was “grossly underestimated” and “evidence strongly suggests that others may have been exposed to higher levels” as well.

“It also clears the way for others and that’s important to me,” said Wilborn.

"I’ve worked with a lot of guys down there who are my friends and I have memories of them—men who had cancer and were dying and had claims before the V.A.”

One of them is the widow of former navy serviceman Charlie Swinney. Swinney, who died in 2010, begged his wife to promise she would find someone to investigate suspicions that the reactor was responsible for so many cancer claims.

Elaine Swinney is still awaiting a decision from the V.A in her husband’s case, but says this new ruling has given her hope.

“It definitely gives me hope,” said Swinney, “It gives me a lot more energy to follow through.”

Meanwhile, medical costs for Swinney forced bankruptcy and left her with few personal possessions—including the violin she often played for her husband to soothe his pain.

“We lost everything,” said Swinney.

The Disabled American Veterans in Washington has been a leading advocate for service related claims and called the appeal board ruling “very significant."

Garry Augustine is the DAV’s Executive Director and says several additional cases—as many as five—will need to be approved by the V.A. before “a precedent is set” regarding McMurdo claims.

“The medical report in this case was overwhelmingly in favor of the veteran,” said Augustine, who advises veterans with similar claims to consult with medical experts in low-level radiation and provide thorough documentation when seeking a service related claim.

The DAV has regional field offices that routinely help veterans maneuver through the labyrinth of V.A. rules and regulations.

“In this case,” said Augustine, “you discovered that these people who were serving up on this post were exposed to radiation that may have never come to light if you had not done your investigation.”

The V.A. declined comment but we have found there at least 26 additional cancer claims pending.