The future of Florida's promised exemption from President Donald Trump's offshore drilling plans is more doubtful after the head of the federal department in charge of natural resources has quit.

Nearly a year ago, U.S. Secretary of the Interior Ryan Zinke told Gov. Rick Scott that any new plans to expand offshore drilling wouldn't include Florida, giving the Republican an environmental victory just before he launched his Senate campaign.

"Florida is obviously unique," Zinke said alongside Scott at a hastily assembled January news conference in a Tallahassee airport. "For Floridians, we are not drilling off the coast of Florida, and clearly the governor has expressed that it's important."

MORE: Rick Scott and Trump administration strike deal: No drilling off Florida coast

But Zinke's resignation over the weekend amid an ethics investigation — the fourth Trump cabinet member to leave under a cloud of scandal — has left many wondering: Was there ever really a deal?

The Trump administration has yet to unveil a long-anticipated proposal to expand offshore drilling along the east coast, including the Gulf of Mexico, and off of California and Alaska. A framework was expected by the end of the year, but the U.S. Department of the Interior wouldn't say Tuesday whether Zinke's departure alters that timeline.

It means Zinke leaves without any official, written acknowledgement that what he said in January is actually department policy.

Democrats and environmentalists say they have reason for doubt. Just days after Zinke's Tallahassee trip, the head of the Bureau of Ocean Energy Management, the Interior Department agency that manages offshore leasing, said the secretary's announcement was "not a formal action."

Zinke in March told the House Committee on Natural Resources that "Florida did not get an exemption," from the administration's offshore oil drilling plan.

MORE: Does Interior Secretary Ryan Zinke have amnesia?

Rep. Kathy Castor, D-Tampa, said that was all she needed to confirm Zinke's appearance alongside Scott was "simply a political stunt." Rep. Charlie Crist, D-St. Petersburg, is so convinced an exemption doesn't exist that he plans to work in the next Congress to ensure drilling off Florida's coast is banned by law.

A moratorium prohibiting offshore drilling within 225 miles from most of Florida's coastline expires in 2022.

"Floridians need clarity and resolution on the issue of offshore drilling," Crist said. "The reported deal with Secretary Zinke was never codified, never formally enacted. The public is right to be concerned that this issue is still very much unresolved."

Scott, who won election to the U.S. Senate last month, once supported offshore drilling when he first ran for governor in 2010. But he now says he would work with the current administration to block rigs off Florida's beaches.

Zinke's interim replacement is Deputy Interior Secretary David Bernhardt, a former industry lobbyist who has overseen a massive expansion of drilling on federal lands.

"Governor Scott was proud to work with Secretary Zinke to protect Florida's coasts and environment," Scott spokesman Chris Hartline said. "In the U.S. Senate, he will continue to do everything in his power to fight for Florida families."

However, Scott has never clarified what it means to "protect Florida's coast." Zinke's initial proposal would have allowed drilling on 25 of 26 regions of the outer continental shelf, which could have brought rigs within a few miles of Florida's coastline.

Conservation groups are gearing up for a less sweeping but nevertheless substantial proposal that would allow drilling 125 miles off Florida's gulf beaches — still 100 miles closer than they are allowed today. Scott has not said whether he would support that change.

"At what point is it considered drilling off Florida and what point is it in the middle of the Gulf of Mexico?" said Frank Jackalone, director of the Florida chapter of the Sierra Club. "Scott has refused to define that. That's where he's been evasive."

Castor said she will work with the Florida delegation to extend the existing drilling moratorium beyond 2022. She hopes she has an ally in Scott.

"He'll have an opportunity to put his money where his mouth is," Castor said of Scott, "and prove it's not just election year talk."