The United States Postal Service is moving forward with a plan that, if ultimately approved, will shut down Wareham's mail processing center along with roughly 250 processing plants across the country.

Postal Service officials cited the "on-going financial challenges caused by the dramatic and continual decline in First-Class Mail volume" as the reason for seeking the change.

The plan would consolidate services and reduce operating costs by $20 billion by 2015 and generate about $2.1 billion in savings per year, according to a United States Postal Service statement.

About 100 employees work for the Wareham plant. The work would be shifted to a plant in Providence, R.I. If the closure is approved, the employees, who are covered by a union contract, would have the option to apply for positions that would be created by the increased volume in Providence.

In addition to the shuttering of plants, the plan would eliminate overnight service for First-Class Mail, changing to a 2-3 day standard for the contiguous U.S., according to the Postal Service. There would still be an opportunity for mail to be delivered the following day for mailers who properly prepare mail and get it into the processing center before a certain hour.

Additionally, two-day delivery would be expanded and some current two-day service would be moved to the three-day delivery range, according to the Postal Regulatory Commission.

By law, the Postal Service must request an "advisory opinion" from the Postal Regulatory Commission, an independent federal agency that oversees the U.S. Postal Service, regarding any change in nationwide mail service. The Postal Regulatory Commission acknowledged receiving the request, but did not immediately issue a schedule for its decision on the case.

The Postal Service will seek public comment about the changes in the near future.

"We will offer a fair and balanced analysis of the proposal. The Postal Service will have the benefit of gaining greater information about the impact of their proposal and the opportunity to make adjustments suggested as part of the public review," Postal Regulatory Commission Chairman Ruth Y. Goldway said in a statement.

Postal officials announced in September that they would be exploring whether it could shut down plants without impacting service to consumers. Only the processing of mail, not any of the Post Office's retail locations, would be affected by the change.

The Postal Service is funded fully through the sale of postage, products, and services. It receives no tax dollars.