Sen. Daniel Akaka says he has “grave concerns” about the future of the United States Postal Service, which is facing financial collapse.

In a Senate Homeland Security and Government Affairs hearing to discuss the service’s financial crisis on Tuesday, Akaka described the cost of prepaying retiree’s health benefits. 

“This nearly $5 billion per year burden threatens to bankrupt the Postal Service,” Akaka said in a statement provided by his spokesman. “The core of any proposal to save the Postal Service must address this immediate issue by eliminating or off-setting the payment.”

As the USPS approached the end of its fiscal year, it has barely enough money to operate and has billions of dollars in costs, according to The Washington Post.

Akaka acknowledged that structural reform is needed, but said he has concerns over proposals to reduce delivery service, modify collective bargaining or close some post offices. 

“As Chairman of the Federal Workforce Subcommittee, I have grave concerns over these issues and how and if they should be implemented,” Akaka said.