Two Democratic senators are blocking a final vote on President Barack Obama's nominee for Veterans Affairs' top health post over a dispute involving benefits for Air Force reservists who were possibly exposed to Agent Orange.

Sens. Sherrod Brown of Ohio and Ron Wyden of Oregon say they will hold up David Shulkin's nomination until the VA provides more clarity regarding its coverage for 1,500 to 2,100 reservists who served from 1972 to 1982.

The VA is mulling a plan to make it easier for reservists to receive disability benefits if they worked on aircraft containing Agent Orange residue.

If confirmed, Shulkin, who is president of Morristown Medical Center in New Jersey, would fill a vital VA undersecretary post, managing a system responsible for 9 million veterans in over 1,700 facilities.