House lawmakers sparred Wednesday over proposals to buoy the beleaguered U.S. Postal Service, with Democrats offering an alternative plan and voicing concerns that Congress runs the risk of improperly considering the fates of hundreds of thousands of postal workers as it debates the future of mail delivery.

Facing about $10 billion in year-to-year losses, the Postal Service has warned that it will not be able to pay about $5.5 billion in retirement and health-care costs as required by law when its fiscal year ends next week.

In an hours-long afternoon session, a House subcommittee with jurisdiction over the Postal Service advanced a GOP-backed measure that would allow the agency to end Saturday mail deliveries, sell advertising space at post offices and on mail trucks, and phase out most residential to-the-door deliveries in four years, requiring customers with mailboxes at their front door to use curbside boxes or a neighborhood cluster box. The bill also would require postal workers to pay more toward retirement and health-care benefits, and establish a financial control board to overhaul postal finances.

The panel’s Democrats failed in their attempt to amend the measure and voted against the GOP plan, fearing that a control board could elect to lay off thousands of workers at a time of increased unemployment. In response, they unveiled a new plan that would require the federal government to return about $7 billion to the Postal Service that it has paid over the years into a federal retirement account. The money, Democrats said, could be used to offer buyouts or early-retirement incentives to eligible postal workers.

The Democratic plan also would permit the Postal Service to raise postage prices beyond the rate of inflation and enter into new lines of business, including check cashing and the leasing of its excess space.

Rep. Elijah E. Cumnmings (Md.), the top Democrat on the full House committee with postal oversight, said Wednesday that postal employees “work tirelessly to try to right size the organization, and the one thing we don’t want is just throwing people out of the system without trying to work with them.”

“These people have given their blood, their sweat, their tears to make sure that our mail has been delivered for years,” Cummings said, urging lawmakers to consider the fates of postal workers with “compassion.”

Rep. Darrell Issa (Calif.), co-sponsor of the GOP bill, later agreed.

“The last thing I want to do is to tell permanent postal workers that we're going to abruptly have them leave the service before they receive their full pension that they anticipate, and without any compensation.”

But Issa said any serious reform plan will have to trim the postal workforce.

“We have two fundamental things that we can do to reduce that loss related to labor,” Issa said. “We can reduce the pay and benefits of those hard-working men and women, or we can right size the number of people and fully compensate those who are no longer needed.”

“The third choice, . . . which is we will increase the price of postage, is a fool’s errand,” Issa said. “Ultimately, you can only go so far before you force more and more people out of using the post office.”

The bill will be considered by the full House committee in two weeks, aides said. Even if the bill earns a full House vote, it would have to be merged with competing Senate proposals that include some, but not all, of the ideas discussed Wednesday.

The White House also unveiled plans Monday as part of broader deficit-reduction proposals that mostly mirror the House Democratic plan and also would permit the end of Saturday mail.