If the shutdown stretches into late October, the Department of Veterans affairs won't be able to cover November benefits.
That shortfall could impact some 5 million veterans, survivors, and dependents.
VA secretary Eric Shinseki says a prolonged shutdown would leave the department with $2 billion to cover $6.25 billion in monthly claims due next month.
That means about 3.8 million veterans won't receive disability next month.
Pension payments would also be stopped for 315,000 veterans and 202,000 surviving spouses and dependents.