Fuel Spill Threatens Water Supplies : Pollution: Thousands along Pittsburgh area river face conservation orders. Officials fear “the worst of this is yet to come.”

Nearly 1 million people in the Pittsburgh area faced voluntary and mandatory water conservation orders Monday as treatment plants shut off intake valves against a 200,000-gallon fuel spill in the Allegheny River.

Officials in Pittsburgh said the city was still pumping uncontaminated water from the river, and the spill appeared to be dissipating somewhat.

The Pittsburgh Water Department, which serves 450,000 people, was boosting its reservoirs Monday afternoon but was preparing to close its intakes at any moment. If the spill “should move suddenly, we’ll have to shut the plant,” said Mayor Sophie Masloff.

“I think it’s very possible the worst of this is yet to come,” said the city’s public safety director, Glenn Cannon. “There’s no end to it.”

The 20-mile-long slick, estimated to be between 5 and 21 feet deep, worked its way south toward Pittsburgh at a rate of about half a mile an hour.

The slick was expected to take at least four days to move through the Pittsburgh area, where the Allegheny joins the Monongahela River to form the Ohio River.

The regional office of the federal Environmental Protection Agency said that Pittsburgh did not face a water emergency. Even if the city was forced to shut its intake valves, it could draw on water in tanks and reservoirs while the mixture of gasoline and other petroleum products moved downriver.

Hardest hit by the spill was the nearby community of Harrison Township, which remained without water Monday. Trains hauling tank cars filled with fresh water were sent to the town, officials said.

The nearby Wilkinsburg-Penn Joint Water Authority resumed pumping from the Allegheny for its 200,000 customers later Monday.

Orders to conserve water were issued to at least 400,000 other people served by various water authorities northeast of Pittsburgh.

At least nine school districts closed Monday, idling more than 21,000 students, and many businesses were affected by the spill.

State emergency officials trucked in water to replenish a 45,000-gallon reservoir at Allegheny Valley Hospital, which draws its water from the river. The hospital used paper plates and cups to serve meals to its 225 patients, closed its laundry and was sending dirty linens to another hospital.

Local officials were sharply critical of the Buckeye Pipeline Co., whose conduit ruptured Friday in Freeport, Pa., about 30 miles north of Pittsburgh, despite the pipeline company’s promise to accept full responsibility for the spill and the yet undetermined cleanup costs.

Allegheny County Commissioner Pete Flaherty said he asked the state to investigate Buckeye’s pipeline, saying: “There are not enough shut-off valves in that area of pipeline,” referring to the section that ruptured. “I feel a pipeline serving an urban area should be better protected.”