Thousands of gallons of water failed to control a chlorine plant blaze that raged for a second day Saturday, sending clouds of gas over the city, injuring 275 people and forcing the evacuation of up to 30,000 residents.

The city's five pumpers were turned on the Advanced Laboratories factory in hopes of "turning the plant into a big swimming pool," said Fire Department spokesman Giorgio Placanico.The attempt to extinguish the blaze remained unsuccessful late Saturday. Fire engulfed the four-story building, sending flames 100 feet high and spreading the chlorine cloud about two miles long and four blocks wide.

Seven of the 125 firefighters battling the blaze were injured Saturday night. More were on call from neighboring towns, Placanico said.

"We're flooding it with everything we have," he said.

Placanico said 20,000 to 30,000 people were evacuated and buses still were transporting residents away from the area early Sunday.

Earlier, the city extended an evacuation order to one mile around the plant and 11/2 miles to the northeast, where winds carried gas clouds hundreds of feet tall over a residential area. Two city high schools and a hospital were opened to house the evacuees.

At least 150 people Saturday and 125 people Friday were treated at three city hospitals for skin burns and respiratory problems caused by the fumes, authorities said. There were no reports of serious injuries.

"I don't need this and my kids don't need this," said Kathy Trucx, an evacuee at Municipal Hospital, who said her two children suffer from bronchitis.

Authorities said they were abandoning an earlier plan to use 52 tons of neutralizing chemicals after dawn Sunday to try to put out the blaze at the plant, which makes swimming pool chemicals.

"We just decided we can't wait until morning," Placanico said. "It was too dangerous to leave alone."

The center of the fire Saturday was a room containing 600 to 800 barrels each filled with 300 pounds of granulated chlorine. The dry compound is 90 percent chlorine, Placanico said.