(CNN) -- Officials in Panama City, Florida, have beaten construction delays, permit problems and the ever-present threat of hurricanes to arrive at this day: a new airport that will open the region to the world and bring in planeloads of tourism dollars.
But as regular air service begins Sunday, authorities never thought they'd have to contend with a new threat: an oil spill in the Gulf of Mexico that continues to gush thousands of gallons of crude every day.
"We've been getting calls ever since the oil spill occurred," said Dan Rowe of the Panama City Visitors' Bureau. "You know, wondering about their vacation plans."
Tourism, Rowe said, is the largest industry in Panama City. The $318-million Northwest Florida Beaches International Airport is the first international airport to open in the country since 1997.
"It is really going to be an economic driver for all of northwest Florida's economy for years to come," he said.
The new airport is expected to generate approximately $80 million in new state revenues over the first 20 years of operation.
But the challenge, now, is to convince tourists that the water is clean.
"We'll get through the oil spill," Rowe said. "There's no oil on Panama City Beach or any of the beaches in northwest Florida."
Indeed, the spill is more than 100 miles away from Panama City Beach's coastline. Local officials have said that if it comes ashore, they will swiftly deal with it.
Yet, beach towns across the Gulf coast have seen business slide precipitously as tar balls -- pieces of emulsified oil -- wash ashore along the coasts of Mississippi and Alabama.
Florida Gov. Charlie Crist asked oil company BP, which owns the damaged well at the heart of the slick, to pay for a $35 million advertising blitz to reassure tourists that Florida beaches remain untarnished by the spill.
Oil has been gushing into the Gulf at the rate of about 5,000 barrels a day (210,000 gallons) since late April, when the drill rig Deepwater Horizon blew up and sank about 40 miles off Louisiana. Some estimates have put the amount of oil spewing from the well far higher.
Eleven workers are missing and presumed dead after the explosion and sinking, and the cause has not been determined.
Efforts to shut down the well that was ripped open by the accident have failed so far, though BP says it has been able to capture some of the escaping oil and pump it to a ship on the surface.
The company also said it will continue using a controversial subsea dispersant to break up the plume of oil, pushing back against a directive from the Environmental Protection Agency to find a less toxic alternative, the EPA indicated Saturday.
The EPA issued the directive on Thursday, ordering BP to find within 24 hours a less toxic but equally effective chemical than its current product, Corexit 9500, and one that is available in sufficient quantities. The directive also gave the company 72 hours to stop applying it to the undersea gusher.
Corexit has been rated more toxic and less effective than many others on the list of 18 EPA-approved dispersants, according to testimony at a congressional hearing Wednesday.
The EPA released BP's response to the mandate on Saturday.
The response, which BP submitted late Thursday night, said that the oil company identified the only other effective, less toxic alternative available in mass quantities as Sea Brat 4. However, BP said the Sea Brat product "contains a small amount of a chemical that may degrade to a nonylphenol."
Nonylphenol is an organic chemical that is toxic to aquatic life and may persist in the environment for years.
Corexit, however, "does not contain chemicals that degrade into NP (and) the manufacturer indicates that Corexit reaches its maximum bio-degradability within 28 days of application" and does not persist in the environment, BP's response said.
"Based on the information that is available today, BP continues to believe that Corexit was the best and most appropriate choice at the time when the incident occurred, and that Corexit remains the best option for subsea application," BP said.
Also Saturday, the Department of Homeland Security announced that Interior Secretary Ken Salazar and Homeland Security Secretary Janet Napolitano will lead a bipartisan Senate delegation to inspect the Louisiana coastline after globs of thick, heavy oil began washing into some of the state's marshlands this week.
The delegation will meet with federal officials and BP representatives to discuss the ongoing response efforts.
CNN's Ed Lavandera contributed to this report.