An ambitious attempt to overhaul the nation’s mail system may not make it to the House floor for a vote this year, leaving lawmakers to pass another stopgap measure to shore up postal finances, congressional aides and industry observers said Thursday.

The Senate passed a postal reform package in late April, and postal officials and mailing industry leaders hoped the House would move quickly to pass a competing package and negotiate a final bill before the fiscal year ends Sept. 30. But House Republican aides and industry observers confirmed that despite public comments to the contrary, no bill is expected to be considered before lawmakers leave for a month-long recess in August.

Just eight legislative days will remain in the fiscal year when the House returns in mid-September, leaving little time for Congress to change the current law that requires the U.S. Postal Service (USPS) to pay about $5.4 billion by Sept. 30 to pre-fund future retiree health and insurance obligations. So lawmakers may once again do what they did last year: allow the service to pay its annual obligations later in fiscal 2013.

Last year’s payment of roughly $5.5 billion is due Aug. 1 and, unless Congress again allows the service to pay later, the fiscal 2012 payment of roughly $5.6 billion is due in September, according to USPS spokesman David Partenheimer. Those two payments, plus declining revenues, means the Postal Service is expected to lose $14 billion this fiscal year, Partenheimer said.

“Legislative changes are a vital component of the Postal Service’s comprehensive five-year business plan that would reduce our annual costs by $22.5 billion by 2016 and put the Postal Service on the path to long-term financial stability,” Partenheimer said in an e-mail.

But aides to House Majority Leader Eric Cantor (R-Va.), who sets the House schedule, said Thursday that he hasn’t determined when lawmakers will vote on a reform bill. GOP leaders are aware of the dates by which USPS is obligated to make payments to fund health-care and retirement costs, said the aides, who spoke on the condition of anonymity in order to speak frankly about scheduling issues.

The GOP postal reform proposal, cosponsored by Reps. Darrell Issa (R-Calif.) and Dennis Ross (R-Fla.), differs significantly from the bipartisan Senate deal. The Issa-Ross plan allows USPS to end Saturday mail delivery, streamline postage rates and require postal workers to pay the same health insurance premiums as federal employees. It also establishes a financial control board to overhaul postal finances and a separate commission to recommend which postal facilities should close.

The Senate deal, cosponsored by Sens. Joseph I. Lieberman (I-Conn.), Thomas Carper (D-Del.), Susan Collins (R-Maine) and Scott Brown (R-Mass.), would bar USPS from ending Saturday delivery for two more years and places several geographic and economic restrictions on closing rural post offices.

“The House’s continued unwillingness to act on this issue is completely irresponsible,” Carper said in a statement Wednesday, adding later: “The longer the House delays action, the more consumers and businesses become uncertain about the future of the Postal Service, undermining confidence in the Postal Service’s future and harming its ability to build new business.”

Ali Ahmad, an Issa spokesman, said the GOP legislation has sufficient support and that any delay “is intended to ensure that meaningful reforms not only win House approval, but are ultimately signed into law by the president. Issa and House leadership continue to monitor the Postal Service’s efforts to implement all cost-cutting measures they are able to do under current law as well as the Postal Service’s financial condition to ensure that there is no disruption in service.”

Even if the House and Senate strike a deal, it’s likely to leave USPS officials unhappy. For more than three years, postal leaders have pushed lawmakers to grant them full flexibility to set delivery schedules, postage rates and the location of postal retail outlets. But lawmakers do not seem eager to make significant changes in the midst of an economic downturn and election year.

Any delay “is potentially disastrous for the 8 million private sector workers whose jobs depend on the mail,” said Art Sackler, a leader of the Coalition for a 21st Century Postal Service, a group representing mailing industry firms. “This issue is critically important to the economy, and the House needs to have its voice heard.”