If oil spewing from a broken BP well in the Gulf of Mexico reaches South Carolina, it will have formed into balls ranging in size from marbles to tables by the time it arrives.
The balls can be squished under a bird's foot.
They can melt on a beach after a few hours in the sun.
They can fall apart when brushed by fishing nets.
Squished, melted or broken apart, the so-called tar balls ooze an orangey, sticky smear of toxic oil.
If tar balls reach the S.C. coast, they could disrupt shrimp and oyster harvesting, harm shorebirds and turtles in their hatching season, and foul small parts of beaches, said Jacqueline Michel, who runs a Columbia research firm that has responded to hundreds of oil spills worldwide.
Her 33-year-old firm, Research Planning Inc., has been contracted by the National Oceanic and Atmospheric Administration to help organize the cleanup from the BP spill.
However, the chances are greater that tar balls from the Gulf will not come near the S.C. coast.
Michel said the NOAA estimates tar balls have somewhere between a 1 percent to 20 percent chance of reaching the S.C. coast in late July or early August -- the middle of the summer tourist season.
"That's when it starts," she said. "It will keep coming."
Decades to restore
BP does not expect to have a relief well - considered the best hope to stop the leak - in place until August.
The Deepwater Horizon well has been leaking since April 20, sending a plume of oil into the Gulf of Mexico.
As more oil streams into the Gulf, concerns rise that some could travel around Florida, up the Gulf Stream and onto the Atlantic coast.
S.C. officials have been told they should have about 45 days to put a response plan into action if the oil comes around the Florida peninsula.
"Nobody expects anything to happen so rapidly that we couldn't gear up," said Priscilla Wendt, a marine biologist with the S.C. Department of Natural Resources.
In the wake of the spill, Madilyn Fletcher, director of USC's School of the Environment, said she fears the oil could produce oxygen-depleted areas where fish might suffocate, and food for fish and birds would be contaminated.
"This is along the lines of a volcano destroying land," she said.
"Those things have happened on the planet for millennia, and animals and the habitat have adapted. ... [But] faced with this amount of oil and toxins, habitats cannot adapt.
"It could take decades or a century for everything to be restored," Fletcher said.
Oil from the BP spill would travel along the Loop Current around Florida before reaching the Gulf Stream, which is more than 50 miles off the S.C. coast. State officials and fishing industry leaders acknowledge some oil could break away from the current and reach South Carolina, but they do not think it will be a significant amount.
"It will have a hard time getting here," said Frank Blum, executive director of the S.C. Seafood Alliance.
The hurricane season, which started June 1, could change that, however. A storm could push oil out of the Gulf Stream and bring it toward shore, Michel said.
Development of a potential response plan already has started with meetings involving the S.C. Department of Health and Environmental Control and the U.S. Coast Guard, the lead agencies in case of a spill, and the Department of Natural Resources, which would enforce fishing bans and help rescue wildlife.
The worst previous oil spill along the coast in recent years was in 2002, when 12,500 gallons of oil spilled from a ship in Charleston harbor. The oil spread out over dozens of miles of coast and marsh, from the former Navy base property on the Cooper River to Folly Beach.
After a spill from a cargo ship, tar balls and oil were found in the water and on beaches around Charleston, including Fort Sumter, Folly Beach, Kiawah Island and Edisto Island, last October, the Coast Guard said.
'Could taint them'
Tar balls do not cause as much widespread damage as the rawer oil hitting beaches and marshes in Louisiana, Mississippi and Alabama.
But they could hurt some of the wildlife and habitats that make South Carolina unique, said Michel, whose firm has developed several coastline environmental maps for the National Oceanic and Atmospheric Administration.
Turtles could be harmed because they could mistake the tar balls for food, said Michel, looking over maps of the S.C. coastline that show where wildlife lives.
Birds that dive into the ocean for food -- gulls, terns and pelicans -- also could break tar balls and get coated with oil. Shorebirds -- sandpipers, peeps and willets -- can mash tar balls that wash onto beaches and get oil on their legs and feet.
While most fish can metabolize oil, shellfish cannot. "It's probably not enough to kill oysters, but it could taint them," Michel said.
Workers would need to scoop away sand on parts of beaches where tarballs have melted, she said.
But cleanup crews cannot do much if the tar balls reach sensitive marshes. The best solution would be to let Mother Nature work, she said.
Booms could be used to help protect the most environmentally sensitive areas, Wendt said, especially if the oil arrives on the S.C. coast at the height of the nesting season for sea turtles and sea birds.
But booms could be tough to use, Michel said, because they cannot cover the bay openings of estuaries and might not stop oil in the Lowcountry's stronger tides. "It could be hard to tackle," she said.
At the leak
A cap placed over the gusher was believed to be collecting anywhere from about a quarter to half of the leaking oil. The government's point man for the crisis, Coast Guard Adm. Thad Allen, said at a news briefing Saturday that the cap collected about 252,000 gallons of oil Friday, its first full day of use.
The goal is to gradually raise the amount of the oil being captured, Allen said. The device's daily capacity is 630,000 gallons, and officials estimate about a half-million to a million gallons a day are gushing out. The well has leaked about 23 million to more than 46 million gallons since the crisis began, according to government estimates.
The Associated Press contributed to this report.