WASHINGTON — Charles Clark knew something was wrong when he started losing his teeth at age 37.

"They just fell out — no blood," the Hawai'i resident said.

He is virtually certain it had something to do with his Navy service in the Pacific during World War II, when he was exposed to atomic bomb radiation.

On Sept. 23, 1945, the 17-year-old sailor entered Nagasaki, Japan, where six weeks earlier the world's second nuclear weapons attack had killed 80,000 people. Some died due to massive doses of radiation.

Clark remained in Nagasaki for five days, setting up ship-to-shore communications. It would forever change his life.

Since then, "I've had more than 180 skin cancers removed from my face," he said in a recent interview. "Even today, the cancer keeps recurring. It never stops."

Clark is among a group called the "Atomic Vets" — American military veterans exposed to radiation from nuclear weapons.

Between 1945 and 1962, half a million U.S. troops participated in more than 250 atmospheric and underwater atomic bomb tests, most in the Pacific and Nevada. Many of these veterans have since suffered a panoply of illnesses commonly associated with radiation exposure, but many have had trouble getting the care they need.

Rep. Neil Abercrombie, D-Hawai'i, has introduced legislation that would streamline the process and add transparency.

"These veterans are dying every day from diseases caused, at least in part, by their service in atomic tests and other nuclear weapon-related activities," the 11-term congressman said.

The treatment process is run through the Department of Veterans Affairs using data from the Defense Threat Reduction Agency.

Typically, the process entails a veteran approaching the VA with a claim. At that point, the agency sends the information to the DTRA, which decides whether the veteran's service record indicates past exposure to high doses of radiation.

This process, known as "dose reconstruction," can take months and occurs behind closed doors, critics say.

It can be cumbersome and mysterious, especially for someone already dealing with a life-threatening illness.

The DTRA and the VA recognize 22 types of cancer that qualify as caused by radiation exposure. Some cancers must occur within a particular time frame, such as 20 years from exposure, to qualify.

More than 90 percent of the veterans who apply for benefits outside the set parameters are denied, according to research Abercrombie's staff has done.

Abercrombie's legislation, the Atomic Veterans Relief Act, would add transparency by opening up DTRA's analysis methods.

There is no companion bill yet in the Senate. Abercrombie introduced his legislation around Memorial Day. He hopes it will pick up momentum as stories like Clark's circulate, and as lawmakers gain appreciation for the sacrifices of war through the prism of two ongoing conflicts.

"We're trying to get some certainty in the process," said Abercrombie, who is running for governor in a state with a large retired military population.

DTRA spokeswoman Kate Hooten said the agency has well-established protocols for determining radiation exposure, and she noted that over the decades, many veterans have scattered across the globe and are out of touch with government health care networks.

"This is an important issue," she said. "We're always interested in finding out how we can reach out to the public."

VETS REMEMBER

To make the case for his reform legislation, Abercrombie has collected the narratives of some veterans who worked around nuclear tests and are suffering multiple cancers and other ailments.

Edward Blas, who lives on Guam, was stationed in the Marshall Islands during the cleanup on Eniwetok Atoll after 43 nuclear tests there.

"The evidence was overwhelming that we were exposed to high levels of ionizing radiation while we lived on ground zero," he wrote.

Despite the fact that he has never smoked, Blas is anemic and diabetic and weighs half the 220 pounds he did in the service. But his medical claim was denied on the grounds that veterans who served there after the nuclear tests were not considered "atomic vets."

But those were different times. Not much was known about radiation exposure.

In the early days of the nation's nuclear program, Cold War imperatives overrode most other concerns.

"I've talked to people who were pretty casual about radiation in the early going," said Richard Rhodes, author of the 900-page Pulitzer Prize-winning book "The Making of the Atomic Bomb."

"We were at war and we had to take some risks," Rhodes said in an interview this week.

For Clark, the risks went further than his own body.

His daughter lost both breasts, while his granddaughter suffers from skin ailments, all of which he is convinced can be traced back to Nagasaki.

"We just never understood what we were getting into back then," Clark said. "We were young kids."