Tar balls from the Deepwater Horizon oil leak began to appear in the pristine sugar sand of St. Joe Co.'s Florida Panhandle beaches just this week. But the impact of the continuing massive Gulf oil spill began hitting the company's stock weeks ago.

St. Joe's stock price has fallen nearly 40% since the April 20 accident, down from a recent April 29 high of $37.13 per share to $22.98 Thursday afternoon--despite major company efforts to mitigate negative publicity and perceptions.

The land developer owns 600,000 acres, most of it in Florida's Panhandle and most of it undeveloped. While it owns miles of waterfront property on the Gulf and various creeks and rivers, only 5.7 miles of it is sandy beaches. Unfortunately, most of St. Joe's better-known developments are clustered on those beaches, including WaterColor, WindMark Beach, and WaterSound. That fostered the company's reputation as a resort developer, which has helped the company's stock to slide so precipitously.

The oil spill occurred just when St. Joe's business was showing signs of improvement and diversification. Northwest Florida Beaches International Airport, subsidized by St. Joe to help spur economic development for the region and unlock the value of its acres of raw land, just opened in Panama City Beach in May. The hope is that the airport will attract more military and defense-related industries to the area, which already has a large number of military bases. More industry brings more people, who require homes that St. Joe has plenty of land to provide for.

St. Joe also had recently announced plans to move its headquarters from Jacksonville, Fla., to a commercial development it is building around the new airport, further seeking to cement its commitment to the area.

The company got out of the home building business a couple of years ago, choosing to sell lots to home builders instead. Beazer Homes USA has a partnership with St. Joe to build in the Panhandle, but it declined to comment on the oil spill's impact on its home sales.

When St. Joe released its first-quarter results in early May, its resort division reported increased revenues. Average rates were up as well, especially in its vacation rental segment. Advance deposits were ahead of 2009. Revenues from golf were also higher despite the unseasonably cold weather.

By early May, the company was already getting calls from people who were booked at the company's resorts. St. Joe officials said at the time they would be documenting cancellations related to the spill and adding them to their tally of how much the spill is costing the company in direct costs and loss in revenue.

St. Joe said it has hired a forensic accounting firm to keep the tally current and plans to present the bill to BP. The company is declining interviews related to the impact of the spill, but it is keeping its Web site updated with its preparations and cleanup efforts.

One of the first things St. Joe did in the wake of the spill was to hire The Shaw Group, experts in oil and environmental sciences, to help prepare for the spill and assist in cleanup and testing.

"Before" samples of the beach sand as well as photographs of the company's land were taken to provide evidence of any damage. And the company set up an active Web site, www.joe.com, chronicling the spill's effects and its reaction.

The company also has built sand berms at lakes and outfalls hoping to keep the oil from reaching farther inland.

Marble-sized tar balls started arriving last weekend on St. Joe's beaches, and St. Joe announced Wednesday it had hired Interstate Restoration Group to assist in oil remediation efforts on its beaches. Thursday, it announced twice-a-day cleanings of the beaches.