Students stole mercury from a lab at Ballou High School in the District yesterday and spread it among classrooms, shutting down the school, authorities said.

No injuries were reported, but the potentially poisonous liquid metal was found in BB-size spheres and pancake-size pools in five classrooms and the cafeteria, said Alan Etter, a spokesman for the D.C. Fire and Emergency Medical Services Department.

The fire department removed much of the mercury, but a private contractor was brought in to scour the school overnight, Etter said.

School officials said the school, at 3401 Fourth St. SE, would remain closed today and throughout the weekend.

The mercury apparently was taken from a second-floor room sometime after 11:30 a.m. School officials said it was stored in an unused honors chemistry lab that is scheduled for renovation. Etter said the room should have been locked, but school officials said it was temporarily unlocked.

Etter said fire inspectors found other potentially hazardous chemicals in the room and had told the school to store them properly.

Witnesses said they saw students carrying the mercury in a plastic bag and one female student flinging mercury with her bare hands, "watching it splatter all over the wall," Etter said.

Theodore Tuckson, acting head of security for D.C. public schools, said building maintenance personnel called the fire department after seeing the silver metal. Students were evacuated to a football field and dismissed at 3:15 p.m.

Yesterday evening, Tuckson said that his investigators did not know which students were involved or even how many.

Neither the fire department nor the school system could say how much mercury had been stolen or whether students had taken any of the metal away with them.

Etter said that anyone who had touched the mercury should wash with cold water and soap, noting that cold water closes the pores, and then see a doctor. Anyone who finds mercury at home should call 911, he said. The school system said parents who believe their children's clothes are contaminated should place the items in a plastic bag, take it outdoors and call the fire department.

School officials said the U.S. Environmental Protection Agency was joining in the cleanup effort and that the school would not reopen until the air is tested and the building deemed safe. They said parents with concerns about mercury could call the National Response Center at 1-800-424-8802.

An away football game scheduled for today will be played, D.C. school officials said.

Staff writer Martin Weil contributed to this report.