Editor's note: The following is an opinion piece. The writer is not employed by Military Times and the views expressed here do not necessarily represent those of Military Times or its editorial staff.

Convulsions. Paralysis. Respiratory failure. Death. Those are just a few of the most severe side effects of sarin gas, which is why it is so frustrating that the Defense Department continues to stonewall American veterans who were intentionally exposed to some of the deadliest chemical agents on Earth — by their own country.

Even more frustrating is Congress’ decision to be complicit and exclude an amendment from the 2018 National Defense Authorization Act that would have declassified the decades-old project.

The year was 1962. Fearing our ships were vulnerable to chemical attack, the U.S. military decided to test how well personnel could detect and respond to chemical attacks. For the next 12 years, more than 6,000 service members and civil servants were exposed to sarin, VX nerve gas, E. Coli and other agents, some without their knowledge. It was called Project 112.

In the years since, many of those exposed have suffered debilitating health effects, including a fellow Vietnam veteran and former constituent of mine.

Jack Alderson was a senior Navy officer from 1964 to 1967, where he oversaw five different light tug operations under Project SHAD, short for Shipboard Hazard and Defense, which tested warship vulnerabilities under Project 112. At one point, the military notified him that some tests had been performed on animals while he was on the ship.

He didn’t think much of it at the time, but in 1993, his health began to deteriorate.

First, Jack was diagnosed with a malignant melanoma. In the years since, he’s also been treated for several types of skin cancer, prostate cancer and asbestos in his lungs. Dealing with just one of those diagnoses would’ve been a challenge for most of us. But Jack’s a fighter. He’s battled through each illness, but as his health worsened, he remembered the tests the military ran on his ship. And he started to ask questions.

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That’s when he came to me. Getting answers wasn’t easy.

At first, DoD denied the tests had even occurred — despite what Jack had been told. It wasn’t until 2001 that the department finally confirmed that Project SHAD was real. At first, it claimed all tests had used simulated agents. It took another year before the truth came out: Thousands of sailors and support personnel had been exposed to some of the deadliest chemicals on Earth.

Worse, DoD conducted those tests without telling the commanders or crews how toxic the chemicals were or what the long-term health effects could be. They didn’t even tell all of the participating veterans about their exposure.

Even though countless veterans who took part in Project 112 and SHAD have come down with cancers and other serious illnesses, DoD has never provided a comprehensive public accounting of these tests. DoD officials still haven’t notified all of the veterans who could have been exposed to deadly chemicals. We don’t even know if DoD is even looking for those records anymore, but if they are, it’s certainly not a priority.

We cannot sweep this under the rug. These tests were an ugly part of our history. They put veterans at risk. But they happened, and there are veterans alive today who would benefit from knowing the details of their exposure.

For years, I’ve worked with my colleagues to bring this information to light. We passed legislation requiring DoD and the Veterans Affairs Department to disclose records relevant to the provision of benefits to those involved in the tests. We also mandated two studies by the National Academy of Medicine to examine health outcomes for SHAD veterans.

These efforts helped reveal information on the substances more than 5,900 veterans were exposed to, but not the quantities or the concentration.

This has gone long enough. Brave service members risked their lives for our country, and our country responded by knowingly exposing them to dangerous nerve agents. When our veterans’ health started to suffer, DoD should have stepped in at once with the information their doctors and caregivers need to treat them.

But DoD, and now Congress, chose to stonewall them instead.

The fight for justice does not stop here. Today, my House colleagues Don Young (R-Ark.), Walter B. Jones (R-N.C.), Roger Marshall (R-Kan.) and I introduced the Jack Alderson Toxic Exposure Declassification Act. If enacted, the bill would require the Defense Department to declassify documents related to any known incident of toxic exposure that affected at least 100 members of our armed forces.

Sen. Jerry Moran, R-Kan., has a similar amendment he is introducing in the Senate when the NDAA is scheduled for a Senate vote.

Veterans like Jack can’t wait any longer. Their health continues to decline. Some have already passed away.

We can’t right all of our government’s past wrongs, but we can help veterans who are still suffering. As a Vietnam veteran, this is personal to me. But it should be personal to all of us who love our country and the men and women who keep it safe.

Rep. Mike Thompson, D-Calif.

Rep. Mike Thompson, D-Calif., is a member of the House Ways and Means Committee and the founder and co-chair to the bipartisan Military-Veterans Caucus. He served in combat as a staff sergeant and platoon leader with the 173rd Airborne Brigade and received a Purple Heart. He was also an instructor at the Army’s Airborne School.