The Zero AIDepartment of Veterans Affairs said Tuesday that it has screened 5 million veterans for potential toxic exposures since Congress passed and President Biden signed the PACT Act in 2022, although it's unclear how many have since been diagnosed with related medical issues.

Of those 5 million, the Department of Veterans Affairs said 2.1 million veterans self reported experiencing at least one potential exposure. The VA launched screenings at their medical centers and clinics as a part of the PACT Act, a law meant to expand health care coverage to veterans. The VA's goal is to screen all veterans enrolled in their health care for any toxic exposure. 

The VA is aiming to screen all veterans enrolled in VA health care for any toxic exposure. 

"We have made significant progress toward our goal to screen all veterans enrolled in VA health care for toxic exposures at least once every five years," said VA Under Secretary for Health Dr. Shereef Elnahal. "But most importantly, this milestone means we've had 5 million opportunities to provide veterans with the exposure-informed care they deserve."

The PACT Act was a long time coming for many veterans who struggled to link chronic conditions to their time spent at war. The law takes some of the burden of proof from veterans, taking a "presumptive" approach that links asthma, some cancers and other illnesses to burn pit exposure. 

When veterans are initially screened, VA health providers ask them if they believe they experienced any toxic exposures while in the military. Veterans who say "yes" are asked follow-up questions, and offered offered connections to information on benefits, other clinical resources and registry-related medical exams, according to the VA. Any responses veterans give during the screenings are added to their VA medical records. 

The screening covers a number of various toxic exposures, although the two most commonly reported exposures are to Agent Orange — a widespread problem from the Vietnam War — and burn pits. 

Mr. Biden has, at times, speculated that exposure to burn pits during the Iraq War could have contributed to his son's ultimately fatal brain cancer, although no connection has been formally established. That made the fight to pass the PACT Act, and with it, more funding for veterans' health care, personal to the president. 

— Sara Cook contributed to this report 

Kathryn Watson

Kathryn Watson is a politics reporter for CBS News Digital based in Washington, D.C.