Sgt. Richard Ganske, 84th Combat Engineer Battalion uses a bulldozer to maneuver trash and other burnable items around in the burn pit at the landfill of Logisitics Support Area Anaconda in Balad, Iraq August 24, 2004. Picture taken August 24, 2004. Pfc.
Sgt. Richard Ganske, 84th Combat Engineer Battalion uses a bulldozer to maneuver trash and other burnable items around in the burn pit at the landfill of Logisitics Support Area Anaconda in Balad, Iraq August 24, 2004. Picture taken August 24, 2004. Pfc. Abel Trevino/U. Reuters / US ARMY

A major bill expanding health care and benefits for veterans exposed to toxic military burn pits in Iraq and Afghanistan passed the U.S. Senate on Thursday, as senators praised their bipartisan work on one of the few issues on which they can find common ground.

The bill eases and expands access to health services and disability benefits for veterans who were exposed to toxic smoke from the U.S. military's use of burn pits on foreign bases until the mid-2010s.

If enacted into law, the bill would cost an estimated $180 billion over the first four years. It would benefit nearly 3.5 million veterans who developed cancer and other illnesses after being exposed to fumes from pits that sometimes were as large as a football field. The pits were used to burn waste including plastic tires, batteries, explosives, human feces and chemicals.

"For too long, our nation's veterans have faced an absurd indignity: They enlisted to serve our country, went abroad in good health, and came back home only to get sick from toxic exposure endured while in the line of duty," Senate Majority Leader Chuck Schumer said in a Senate speech.

He noted that around 80% of disability claims related to burn pits have been rejected by the Veterans Administration. The issue is personal for President Joe Biden, who believes his late son Beau's fatal brain cancer could have been caused by such a pit from when he served in Iraq.

Servicemembers returning home from Afghanistan and Iraq suffered from fatal respiratory illnesses and rare cancers caused by exposure to the open air pits, but were frequently denied coverage or put through protracted self-funded legal battles in order to prove their eligibility.

"The cost of war is not fully paid when the war is over. We are now on the verge of honoring that commitment to American veterans and their families," Republican Senator Jerry Moran said ahead of the vote on Thursday.

"This is a day of our democracy actually working," Democratic Senator Kirsten Gillibrand, who championed the bill in the Senate, said at a press conference after the vote.

The bill will also expand coverage for servicemembers exposed to Agent Orange, a herbicide used by the U.S. military during the Vietnam War.

The measure will now go to the House of Representatives for a vote before being sent to Biden's desk for signature into law.