Detailed Instructions: In this task, you are given a text of many news articles seperated by special token "|||||". Your task is to summarize them.
Q: Hundreds of beachgoers told health officials they felt unwell after swimming last week at oil spill-affected Pensacola Beach, Fla. Scientists cite many unknowns about the safety of swimming and working around the spill. 
  
 Brandon Brewer (l.) of Milton, Fla., walks among oily absorbent booms strung along the coast in Pensacola Beach, Fla., on Tuesday. The Gulf oil spill brought tar balls to the beach, but local officials removed 'no swimming' signs despite recommendations that the beach remain closed. 
  
 Santa Rosa Island officials flew the double-red flag – no swimming – over Pensacola Beach in Florida after a swath of thick oil washed ashore from the Gulf oil spill June 23. 
  
 Two days later, against the warnings of federal health officials and based on a visual survey of the beach, the local island authority director, Buck Lee, reopened the beaches for swimming, urging residents and tourists to come back to the beach. Officials left the ultimate decision on whether it was safe to swim to beachgoers. 
  
 This week, health officials in Escambia County, Fla., which includes Pensacola Beach, reported that about 400 people claimed they felt sick after visiting the beach and swimming in the Gulf. 
  
 The massive oil slick hovering off the shore of the US Gulf Coast threatens an entire tourist season that, in Florida alone, represents $65 million in revenue. 
  
 The situation in Pensacola Beach points to the growing difficulty of balancing the potential and largely unknown health effects of a spill making only localized landfall against the political and economic motivations of hard-hit beach communities facing a canceled summer. 
  
 "Perception is a bigger enemy than reality, because would-be visitors are not willing to really do the research or take even a small amount of risk," says Adam Sacks, managing director of Tourism Economics, a consultancy firm in Wayne, Pa. 
  
 Testing by the University of West Florida in recent days has indicated small amounts of dissolved petrochemicals in the water near Pensacola Beach. 
  
 "There are molecules dissolved in the water and you can't see them," Dick Snyder, a biologist at the University of West Florida, told a local TV station. "We don't know how much of that there is, but we suspect there's a lot," 
  
 Federal officials have urged caution about swimming in areas not only near the spill, but also where oil actually came ashore, and where tides buried some of the oil smudges. Federally managed National Seashore beaches on both sides of Pensacola Beach remained closed to swimming. 
  
 "My recommendation to the Santa Rosa Island Authority was to keep the beach closed until we can get a better handle on the actual material out here and to get more of it up," EPA official Charlie Fitzsimmons told the Pensacola News-Journal June 25. 
  
 Local officials took a different tack. 
  
 Water quality tests that take three days to complete have proven useless because of the daily, even hourly, movement of the slick along the shore, says Mr. Lee, the island authority director. Instead, officials are relying on life guards scouring the 8-mile beach to look for oil – as well as the common sense of bathers. 
  
 "If you see oil in the water, don't swim in it, and hopefully people will have enough sense not to do that," says Lee. As to reports of people feeling sick, he says, "People have different reactions. You and I may go in the water, swim around, look for shells and come out of the water and your eyes may be burning and mine may be fine. It affects different people different ways." 
  
 Another problem for local officials weighing the bathing risks: Scientists don't know the health effects of dissolved petroleum in the water. "Someone needs to invent that test," says Lee. 
  
 From the Pensacola Beach Pier, residents reported seeing families with kids swimming in water near a sheen and a concentration of emulsified oil bobbing on the waves. 
  
 The situation reminds some residents of the 1975 movie "Jaws," in which the mayor and beach businesspeople don't want to close the beach because it would ruin the Fourth of July weekend, despite reports of a man-eating shark in the area. 
  
 The health effects of the oil and chemical dispersants used in the cleanup have become a major issue in the Gulf oil spill. Many cleanup workers are bused in from low-income urban areas, including from Anniston, Ala. A BP contractor told a Monitor reporter at a dock in Bon Seceur, Ala., on June 25, "Don't ask the workers any questions." 
  
 The Louisiana Health Department says 108 workers have become ill from working the oil spill. Some health effects have been attributed to working in heavy hazmat suits in the Gulf summer heat. 
  
 In Pensacola, health officials have swapped advisory signs that urged against swimming for 35 "oil impact" signs along the beach that tells residents to be on the lookout for oil, and to swim at their own risk. The EPA is setting up decontamination stations along the beach to help beachgoers clean oil off their bodies. 
  
 The diverse nature of the spill's effect on beaches has complicated the manner in which officials warn residents – especially as the economic implications are becoming clear. Pensacola Beach is experiencing a hotel cancellation rate of 75 percent as the height of the summer season approaches. 
  
 "We have a situation that changes from one hour to the next, from one tide to the next, from wave to wave, from one wind direction to another," Escambia County Health Department Director John Lanza tells the Pensacola News-Journal. 
  
 Florida Gov. Charlie Crist told the "CBS Morning Show" this week that he went for a swim on Pensacola Beach after BP crews cleaned it up. He said continual testing done by the county has shown that the waters are clean. "There isn't a toxic nature," Governor Crist said. "It's much more of a nuisance than anything at this point. But it is safe." 
  
 Related: ||||| Despite detailed water-quality tests and daily oil-spotting flights, local officials said a lack of federal guidance is forcing them to "wing it" when deciding if local beaches are safe for swimmers. 
  
  
  
  
  
 At a press conference at the Pensacola Beach Gulf Pier on Wednesday, Escambia County and Pensacola Beach officials voiced concern at the lack of information about the health risks of oil washing ashore. 
  
 "The thing that frustrates public officials is there is no science. ... There is no science that you can use to see exactly when it is unsafe," said Keith Wilkins, deputy chief of neighborhood and community services for Escambia. 
  
 Wilkins said the Environmental Protection Agency, the University of West Florida and the county all are testing the water quality at some local beaches. 
  
 The location and frequency of the EPA's water testing is unclear, Wilkins said, but county and UWF officials are testing water in surf zones at six locations — four on Santa Rosa Island and two on Perdido Key. 
  
 Water quality tests are done twice a week, and results take two to three days to be returned from the laboratory. 
  
 Wilkins said recent tests have come back positive for dissolved oil in the water near the beach. 
  
 Testing on Monday, for example, detected crude petroleum at 85 parts per billion at Pensacola Beach Gulf Pier and 51 parts per billion near River Road on Perdido Key. 
  
 The test results confirm what officials have known all along — there's oil in the water — but they don't answer the bigger question. 
  
 "We still don't know what that means for human health concerns," Wilkins said. 
  
 Wilkins said federal health regulations specify maximum allowable levels of dissolved hydrocarbons in things like drinking water, but there are no established limits on what levels are safe for swimming. 
  
 "That data doesn't exist right now ... There is not a nice red flag that pops up in chemical analysis ... that says the water is not safe for health reasons," Wilkins said. 
  
 Wilkins said the EPA is currently developing standards for safe levels in swimming water, but it has not yet released that information to county governments. |||||
A:
Just when they thought it was safe to go back in the water, hundreds of swimmers reported feeling ill after braving the waves when Pensacola authorities lifted the "no swimming" flag. Local officials rejected EPA advice to close beaches and are instead relying on lifeguards to spot oil and on bathers to use common sense and not swim where they see oil, the Christian Science Monitor reports. Local authorities complain that tests to check whether water is safe take 3 days to complete, while the location of oil changes hour to hour. "I went swimming on Saturday in the Gulf, and it was fine," Buck Lee, the official who reopened the beaches, told the Pensacola News Journal. "A day or two later, I might not want to go in there." Some skeptical Pensacola residents say Lee reminds them of the mayor in Jaws who didn't want to ruin business by shutting down beaches to protect swimmers from sharks on a long holiday weekend.