Congressman Tim Ryan, D-Ohio, is urging to extend benefits to Navy veterans exposed to Agent Orange, or dioxin.

Agent Orange was a herbicide used by the U.S. military during the Vietnam War to get rid of forest cover and crops for North Vietnamese and Viet Cong troops, according to History.com. Agent Orange contains the chemical dioxin, which later was found to cause health issues including cancer, birth defects and more.

Ryan penned a letter to Paul Lawrence, the VA Under Secretary for Benefits, to ask him to reconsider his opposition to the Blue Water Navy Vietnam Veterans Act. Ryan says this bill would provide benefits to 90,000 Blue Water Navy veterans who were exposed to dioxin during the Vietnam War.

"I'm extremely disappointed that Under Secretary Lawrence would oppose this bill. Contrary to his belief, there is clear evidence that the Blue Water Navy veterans were exposed to dioxin. Over 90,0000 veterans are looking to us for help. I urge Under Secretary Lawrence to reconsider his position," Ryan said in a release.

The release says that during a Senate Veterans Affairs Committee hearing in August, Lawrence urged Senators to vote against the bill, citing the lack of scientific evidence that an exposure occurred.

Ryan says that several studies have proven otherwise.

"Our veterans have put their lives on the line in defense for our freedoms and security. As a nation, we can honor their service and sacrifice by holding up our end of the bargain and providing them with the care they have earned. The Blue Water Navy Vietnam Veterans Act is a chance to show them our thanks," Ryan said.

The House unanimously passed the bill in June with a vote of 382-0.