WASHINGTON (Nexstar) — During his State of the Union address Tuesday, President Joe Biden highlighted the issue of burn pit exposure and the serious illnesses and cancers veterans are suffering from it.

About 3.5 million post-9/11 combat service members were exposed to toxic burn pits, including the president’s late son, Major Beau Biden.

“I don’t know for sure that the burn pit that he lived near … is the cause of his brain cancer and the illness of so many other troops,” Biden said.

Proving that link is scientifically difficult but on Tuesday, the Department of Veterans Affairs announced it plans to presume nine rare respiratory cancers are a result of burn pit exposure. The agency said veterans afflicted with those deserve benefits.

“Headaches, numbness, dizziness,” Biden said. “A cancer that would put them in a flag-draped coffin.”

But that presumed connection wouldn’t be guaranteed by law. Rep. Mark Takano’s bill, called the Honoring Our Pact Act, would change that.

“We’re going to declare 23 presumptive illnesses that are related to burn pit exposure,” said Takano (D-Calif.)

It’s expected to pass the House but Republicans say despite their support for veterans, Takano’s bill is the wrong solution.

The bill “would expand benefit to more veterans without scientific justification,” said Rep. Mariannette Miller-Meeks (R-IA). “Showing just how slippery a slope this bill would set.”

The Senate has different burn pit legislation. Advocates like Jon Stewart fear the Senate won’t pass the portion that presumes the link between illness and burn pit exposure.

“We cannot allow it to happen and you cannot allow this feeling of unity and hope, and finally being seen, to dissipate,” Stewart said.