WASHINGTON (AP) — Comedian Jon Stewart is pressing the Biden administration to fix a loophole in a massive veterans aid bill that left out some of the first U.S. troops who responded after the Sept. 11 attacks and got sick after deploying to a base contaminated with dangerous levels of uranium.

Special operations forces deployed to Karshi-Khanabad, or “K2,” in Uzbekistan about three weeks after the 2001 attacks. K2 was a former Soviet air base that U.S. forces used to strike Taliban targets inside Afghanistan in the earliest days of the war. The base was a former chemical weapons processing site and littered with Soviet-era debris, including demolished bunkers, missile parts and highly radioactive uranium powder, according to documents obtained by The Associated Press.

It’s not clear why uranium powder was on the ground or how it got there. But it’s worrying those who served at K2. Thousands of K2 veterans in the years since have reported complex medical conditions, some of which are known to be connected to radiation exposure.

“Imagine you’re stationed inside the meth lab on ‘Breaking Bad,’” Stewart said in an interview with the AP. “These guys were exposed to a toxic soup of basically an exploded chemicals and nuclear weapon facility.”

A massive veterans aid bill called the PACT Act that was signed into law by President Joe Biden in 2022 addressed many of the health issues facing K2 veterans. But it didn’t include coverage for radiation exposure at K2.

K2 veterans have pressed the Department of Veterans Affairs for help for years, but so far the VA has not acted. The agency has said it is still studying the issue and looking to the Pentagon for additional information before it determines whether to add radiation exposure as a condition K2 service members can get coverage for.

“All presumptive conditions established by the VA, rather than by legislation, require a factual rationale,” said VA spokesman Terrence Hayes.

It’s been more than 20 years since troops first deployed to K2 and almost two years since Biden celebrated the PACT Act’s passage. But K2 veterans are still facing the claim denials the PACT Act was supposed to fix.

Data obtained by the AP shows the soil at K2 recorded uranium radiation levels up to 40,000 times higher than what would have been expected if it were natural uranium, according to Arjun Makhijani, a nuclear fusion specialist and president of the Institute for Energy and Environmental Research, who reviewed the data.

Even if it were in its least radioactive form, depleted uranium, the soil was up to 24,000 times above what would have been found in nature. Air samples were more than 30 to 100 times the levels that would have been found in normal air samples, Makhijani said.

The radiation levels the health team recorded were significant enough that anyone not wearing protective gear would have breathed in high levels of contamination when the dust was kicked up, especially during activities such as earth moving, Makhijani said.

The radiation data was captured in November 2001 by former Army Sgt. Matthew Nicholls, who was part of an Army environmental health team quickly deployed to collect air, water and soil samples from K2 after local Uzbek workers who were preparing the site for arriving U.S. forces fell ill with headaches, nausea and vomiting.

As the health team walked the base by the demolished bunkers and remnants of missiles, the team found the soil dotted with yellow pebble-sized clumps and powder, and tuna can-shaped containers spilling yellow powder, Nicholls said.

A tool used to detect radiation “went from one click, click, click, to sounding like a fishing reel going off,” Nicholls said.

“That material was scattered all over the place,” he said. Photographs obtained by the AP show Nicholls and his team collecting the yellow clumps and scattered powder.

After the health team reported its findings, the military created a classified base map obtained by the AP where the area was marked “enriched uranium contamination site” to keep tents from being constructed there. But the soil had already been moved by bulldozers and trucks as they pushed up a protective berm, and tents on the other side of the berm were constructed on the soil, directly adjacent to the off-limits fields.

Radiation exposure from uranium can damage kidneys, create bone cancer risk and also impact pregnancies because it crosses the placenta, among other harmful effects, said Makhijani, who previously worked with “atomic veterans” who were sickened by radiation after working at the Bikini Atoll during nuclear weapons tests in the 1940s.

“Uranium goes to the bone,” Makhijani said.

Despite detecting the uranium, the military went forward with using the base for the next four years and built a sprawling tent city there. Heavy wind and rain hit the base frequently, stirring the contaminants there. More than 15,000 troops rotated through from 2001 until 2005, when U.S. forces left.

Since the PACT Act was passed K2 veteran and former Army Staff Sgt. Mark Jackson has sought medical help for severe osteoporosis, had to have a testicle removed and had his entire thyroid removed.

None of the new medical issues he’s experienced since passage of the PACT Act have been covered by the VA. This Friday, Jackson will join Stewart in Washington to press the Department of Veterans Affairs to act faster.

Hayes, the VA spokesman, said the agency is “currently doing extensive research to identify evidence that may demonstrate radiation exposure — including analyzing all claims submitted by Veterans who served at K2. We are working this with the utmost urgency.”

In a statement to the AP the Pentagon said late Monday that its own monitoring of the site “does not indicate the presence of enriched uranium,” and that it is reviewing materials from K2 veterans on the site.

The VA doesn’t have complete numbers of how many K2 veterans are sick so the veterans have had to take it upon themselves to organize and collect data. They have been in touch with about 5,000 K2 veterans. Of those, more than 1,500 have self-reported conditions including cancers, neurological conditions, reproductive system problems, a large number of birth defects and bone conditions, among other issues, said Natalie White, a volunteer for the group. White’s husband, Tech. Sgt. Clayton White, died at age 41 after a long list of ailments including osteoarthritis, grand mal seizures and kidney failure. White was deployed to K2 shortly after the 9/11 attacks.

Stewart has long advocated for the firefighters and emergency personnel who responded to the World Trade Center attacks, and in recent years, for Iraq and Afghanistan veterans who came home with cancers or other serious illnesses after exposures to toxins on the battlefield.

The PACT Act was “an immense improvement” Stewart said. A small adjustment by VA Secretary Denis McDonough to address the radiation exposure at K2 could fulfill the PACT Act’s intent.

He worries some of K2 veterans are running out of time.

“The worst part about it is, those years when they’re sickest, being spent in anxiety and struggle against a system that’s somehow set up to be antagonistic,” Stewart said. “I don’t know why it’s an adversarial system in any way, shape or form. But that seems to be the uphill climb that everybody has to go through to try and get either the benefits or the health care that they’ve earned.”