RIYADH, Saudi Arabia -- With the return of unfavorable weather conditions, Saudi officials grimly predicted yesterday that the giant oil slick in the Persian Gulf would reach key industrial sites along the Saudi coast within two to three days.
Among the threatened sites is a desalination plant at Jubail, the source of much of the country's drinking water. A smaller plant to the north at Safaniya, producing water for an oil refinery, was shut down last week as a precaution against damage by oil-contaminated waters.
"If weather continues as it is now, we might see the first oil in the Jubail area in two or three days," said Nizar Towfik, vice president of Saudi Arabia's Environmental Protection Administration.
Abdul Bar al Gain, the agency's president, said: "I don't think we are optimistic."
Winds aided cleanup experts for most of last week by blowing south-to-north and slowing the oil slick's movement. But they reversed direction Friday and began bringing oil closer to the coast.
Roughly 7 million barrels of oil -- 294 million gallons -- was released into the Persian Gulf last month when Iraq deliberately opened valves at storage facilities. The result is the largest spill in history, presenting cleanup experts with problems nearly impossible to solve.
As expected, weather and natural wave actions are pushing oil deeper into the water. That movement increases the chance that oil-contaminated seas will slip through miles of man-made barriers hurriedly erected around Jubail and Al Khobar, the site of another desalination plant.
"The oil has been in the water some time already, which makes it very difficult to combat," Mr. Towfik said. "It's not for me now to say Jubail or any other plant should be shut down. It's premature to talk about this."
Saudi officials have found it difficult to gather the necessary equipment. Mr. al Gain said his agency remained short of devices to skim oil from the surface and was still flying in booms, the physical barriers floated in front of sites needing protection.