Editor’s note: This article by Patricia Kime originally appeared on Military.com, a leading source of news for the military and veteran community.

Senators have ramped up efforts to add three new diseases to the Department of Veterans Affairs' list of Agent Orange-related diseases, pressing the House and Senate Armed Services Committees to include them in the final version of the national defense policy bill.

Sen. Jon Tester, D-Mont., and 45 other senators sent letters Tuesday to leaders of the committees, imploring them to amend the fiscal 2021 National Defense Authorization Act to add bladder cancer, hypothyroidism and Parkinsonism to the VA's list of conditions linked to herbicide exposure in Vietnam and elsewhere.

The bipartisan group, including four Republicans, said an amendment is needed to support 34,000 "frustrated and desperate veterans living and dying from these health conditions."

"Tens of thousands of Vietnam veterans suffer from these three conditions due to their military service, yet these veterans continue to be denied the care and benefits they have earned and desperately need," they wrote.

The National Academies of Sciences, Engineering and Medicine in 2016 deemed the three illnesses to be associated with exposure to defoliants used during the war.

But VA officials have not added them to the list, saying they are waiting for the results of two studies -- the Vietnam Era Health Retrospective Observational Study, or VE-HEROeS, and the Vietnam Era Mortality Study -- to be reviewed for publication before announcing a decision on whether to broaden the presumptives list.

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VA spokeswoman Christina Noel said Tuesday that the department continues to wait for the study results that will "guide decisions on this issue."

"VA has no announcements on changes to the list of Agent Orange-related presumptive conditions," Noel said. "VA is committed to regular review of all emerging evidence of adverse impacts to Veterans from Agent Orange, but the department will not be announcing new presumptive conditions until this additional research is complete to support an informed decision."

The academies also linked hypertension to Agent Orange in 2018, but the amendment sent to the Armed Services committees does not include the condition, which also is among the most common diseases that affect the elderly.

The department estimates that providing disability compensation and benefits to veterans affected by any of the four conditions, including hypertension, would run between $11.2 billion and $15.2 billion, depending on interpretations of a court ruling.

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But the VA has not released an estimate for covering the roughly 34,000 veterans for the three conditions listed in the proposed amendment.

The House and Senate have both passed their versions of the fiscal 2021 defense bill and a group of members from both chambers is supposed to meet to confer on a final draft. However, the conferees have not been named and a date has not been announced for the conference, making it unlikely that a vote will occur before the Nov. 3 election.

The amendment named in the letter, S.A. 1972, passed the Senate with 94 votes. A similar amendment was introduced in the House by Rep. Josh Harder, D-Calif. Thirty veterans groups and military groups support the proposals.

Many of the senators who signed the letter have constituents affected by at least one of the three conditions. Tester has pressed the VA for years to announce a decision.

"The truth is that more and more veterans are dying every single day because this administration refuses to do the right thing and pay for the cost of war. I'll be continuing to fight tooth and nail until we push this bill across the finish line," Tester said.