WATERVILLE – C.F. Hathaway will not get final word on an $18 million to $20 million Air Force contract for another one to four weeks, federal officials told Sen. Olympia Snowe on Monday.

Hathaway had expected an announcement Monday, but defense officials said their review of bids was continuing, and a final decision could come as soon at Aug. 28 or as late as mid-September.

The five-year contract to manufacture long-sleeve dress shirts for the Air Force is considered important to the survival of the financially strapped shirt maker.

Donald Sappington, the firm’s chief executive officer, has said that Hathaway will likely run out of work at the end of September if it is not awarded the contract.

Hathaway’s owner, Connecticut-based Windsong Allegiance Group, had planned to shutter the Waterville factory this fall before an investment group led by the nonprofit Made in the USA Foundation inquired about buying it.

That sale has not been finalized, with the foundation still trying to line up financing for the purchase.

But Joel Joseph, who heads the Made in the USA Foundation, insists the factory can survive even without the Air Force contract, which calls for 386,000 shirts in the first year, and up to 250,000 a year for the next four years.

Hathaway gets priority in the selection process as an American manufacturer with only 300 employees. But other bidders remain in contention, according to Snowe.

The exact timing of the contract’s announcement will depend on whether the Defense Logistics Agency’s tentative selection is contested, Snowe said.

Meanwhile, Hathaway is waiting to hear on a smaller contract to manufacture dress shirts for the Navy and Marine Corps. That decision could also come in September, Snowe said.