The Fulton County Board of Commissioners Wednesday rejected the lone bid for a $21 million radio system upgrade amid complaints the proposal was drafted so only one firm could win.

Commissioners voted unanimously to reject the bid submitted by Motorola Solutions of Lawrenceville and seek new proposals, which are due next month. The move came after representatives of a firm that did not submit a bid complained about the process.

“I don’t see how I can vote to go forward with the cloud that’s over the bidding process,” said Commissioner Robb Pitts.

Fulton County sought proposals to upgrade and expand a radio system used by thousands of public safety and other employees. The county wants to convert the 20-year-old analog system to a digital one to improve service. But it wants to continue to use some existing Motorola radio equipment that is still valuable, according to Emergency Communications Director Angela Barrett.

The county sent 125 solicitations to companies but received just one response. Representatives of the rival firm, Florida-based Harris Corp., complained that the county’s request was written in such a way that only Motorola could qualify.

“We were excluded from this bid,” James Potter, regional sales manager for Harris, told commissioners at Wednesday’s meeting.

County staffers and a consultant disagreed. They said other companies’ equipment is compatible with the existing Motorola equipment, though Motorola offers the most features. Commissioners didn’t buy it.

“We’re getting a proposal that only one person can win,” said Commissioner Tom Lowe. “That don’t make sense, folks.”

Commissioners rejected Motorola’s bid and directed the staff to solicit new proposals — this time with more leeway for other companies. Proposals are due before the commission’s May 15 meeting.

In complaining about the bidding process, Harris officials contacted county officials outside the purchasing department — a violation of county rules that disqualified them from the initial solicitation. However, they will not be disqualified from the new solicitation.

Potter praised the commission’s decision. “They smelled a rat,” he said.

The commission’s action comes as several north Fulton cities are moving ahead with plans for their own $16 million emergency radio system to replace their existing pieces of the Fulton network. Though city representatives have said they’re willing to work with the county to eliminate duplication and save money, they have not committed to participating in Fulton’s system.

On Wednesday, Fulton officials say they’re tired of waiting for a commitment from the cities.

“Those who want to come in later can come in later,” said Commissioner Bill Edwards, “but we’ve got to move forward with this lifesaving apparatus that we need.”