COLUMBIA, S.C.  — Daydreams of beach sunsets have been replaced by anxious Internet checks for many vacationers headed to the Gulf Coast, while hotel clerks there are busy answering calls about a massive oil spill and whether — just maybe — there’s a shot at a refund. The answer is typically no.

Meanwhile, the phones are also steadily ringing for tourism officials hundreds of miles away at Atlantic Coast beaches like Hilton Head Island, S.C., as they delicately try to lure vacationers away without appearing to profit from the disaster.

The angst is caused by the millions of gallons of oil that have spewed from a well at the ocean floor since an offshore drilling rig exploded in the Gulf on April 20, killing 11 people. Balls of tar began washing up on the white sand beaches of Alabama’s Dauphin Island over the weekend, while amounts ranging from globules to an oily sheen were coming ashore to the west.

Tourism officials from Louisiana to Florida — and their customers — are anxiously watching to see where else the slick could come ashore. Vacationers who have already booked are tracking the spill online, and many have been told they’ll face a steep penalty for backing out.

Karen Muehlfelt tried to cancel her upcoming trip to Destin, Fla., but couldn’t stomach the $1,000 penalty. Her beachfront hotel assured her there were plenty of onshore activities, such as good golf courses and restaurants.

“What’s the best decision to make?” wondered Muehlfelt, a 55-year-old receptionist from Chicago. “It’s hard-earned money. Looking forward to this vacation is what has gotten us through the first part of this year.”

Businesses along the Gulf have the delicate task of keeping customers happy but sticking to policies that penalize for cancellations.

“I think reality has actually hit some of the people — whoa, they aren’t containing it quickly as we thought they might,” said Mallorie Thomas, a travel agent busy answering phones at Total Travel in Birmingham, Ala.

Traditional travel insurance won’t help, because the spill is considered an act of man, not an act of God. Most travel insurance only pays off if travelers can’t reach a destination or accommodations are closed, said Dan McGinnity, a spokesman for insurance company Travel Guard North America. That likely won’t be the case even if oil begins rolling on shore.

New bookings have slowed to a trickle as people wait to see where the oil goes. Normally, hotels might be willing to waive some cancellation fees if they were likely to be able to rent the room to someone else. But the uncertainty of the situation means rooms may remain empty, even with the peak of the vacation season on the horizon.

An increase in cancellations in Panama City Beach, Fla., led six resort and hotel groups to offer a $200 credit toward another visit if the government shuts down the beach or is cleaning oil from the sand and water when vacationers are there.

It’s not just hotels trying to keep customers from bailing. When Destin, Fla., photographer Donna Morgan’s phone rings these days, she knows it’s not going to be a new client.

“We’ve had two cancellations so far. I’ve put a whole bunch more of them off. It’s been exhausting,” said Morgan, who takes wedding photos and family beach portraits. “I sympathize with our customers, but we also have a business to run.”

Elsewhere along the Southeast’s Atlantic Coast, tourism officials are diplomatically trying to snare vacationers who don’t want to risk having trips ruined by the massive spill.

From Miami to Tybee Island, Ga., and up to Myrtle Beach, S.C., phones at hotels and chambers of commerce have been ringing and website traffic is up.

In Hilton Head Island, S.C., officials stress to callers that the destination is closer to Atlanta than Gulf Coast beaches and maybe only an hour farther for people from places such as Nashville, Tenn., said Charlie Clark, spokesman for the island’s Chamber of Commerce.

But the push has to be done carefully.

“We feel for our tourism partners along the Gulf Coast,” Clark said. “No destination wants to see this happen.”

So far, bookings haven’t spiked because a lot of callers are just checking their options, said Lindsay Fruchtl, spokeswoman for the Tybee Island Tourism Council.

“They were not sure if their deposits would be refunded. I think they were mainly checking availability in case they change their plans,” Fruchtl said.

Beaches are big business for Southeastern states. Alabama has just two coastal counties, but visitors spend more than $3 billion a year — better than a third of all tourism money in the state. Tourists spend $60 billion a year in Florida, accounting for nearly a quarter of all the state’s sales tax revenue. And in South Carolina, tourism is the state’s biggest industry, with vacationers spending more than $10 billion a year, the majority of it along the coast.

The oil slick has been similar to a hurricane threat — but the specter of most hurricanes torment coastal residents for a week, maybe two if they form far out to sea. The agony over where the oil will go seems to have no end in sight, said Morgan, who survived and rebuilt after Hurricane Ivan devastated the region in 2004.

“With Ivan, we knew we were going to get help,” Morgan said. “With this, we don’t know if we’re going to get help or how we’ll get help.”

Muehlfelt said she will continue watching the news about the oil spill and weigh her options right up until she hits the road for her 1,000-mile trip with her husband, 17-year-old daughter and 21-year-old son.

Several days ago, though, her plans suffered another blow when storms flooded Nashville, a key point on their trip. “I wonder,” she said, “if God isn’t telling us not to go at this point.”