Police said yesterday they have identified two potential suspects in the mercury contamination at Cardozo Senior High School based on a videotape from a 24-hour surveillance camera.
No arrests have been made. But police officials, speaking on the condition of anonymity because the investigation is unfolding, said the videotape appears to show three male students working together to spread the mercury around the Northwest Washington school.
Two of the students have been identified and police are trying to identify the third, officials said.
The discovery of the mercury Wednesday in several locations inside the school forced officials to cancel classes this week while the building is cleaned.
A schools spokeswoman said yesterday that Superintendent Clifford B. Janey will decide tomorrow whether vapors from the contamination are minimal enough to reopen the school Monday, as he initially planned.
"The final air-quality samples will come back Sunday afternoon. At that time, we'll be able to assess the condition of the school," D.C. schools spokeswoman Roxanne Evans said. "We're hoping for the best."
If Cardozo is closed Monday, classes will be moved to another location, school officials said.
The 830-student school removed mercury, a known carcinogen, from its chemistry lab after a mercury contamination at another D.C. high school in October 2003. When the silver, marblelike droplets were found Wednesday morning at Cardozo, school officials said they suspected that the substance was brought into the building by a "prankster."
D.C. health department officials today will bring a mobile clinic to the school's parking lot to test anyone who left the building Wednesday without being screened for mercury exposure. Officials said that though they tried to keep everyone at the school for the screening that was conducted Wednesday afternoon in the auditorium, about 10 students left before the testing. Today's screening will be from 11 a.m. to 2 p.m.
The spill involved two ounces of mercury, health officials said. Hazardous materials crews from the U.S. Environmental Protection Agency found drops of the substance in two stairwell areas and two corridors, EPA officials said. They said more mercury was found in another hallway, probably tracked there by a student who stepped in the material.
The crews used a chemical to neutralize the mercury. They used mops and vacuums to remove it from the floor, and fans helped clear the vapor from the building.
"Once the mercury is outside, it will fall to the ground," said Wendy Jastremski, community involvement coordinator for the EPA. "Once it's outside, there is no need for concern."
D.C. Health Director Gregg A. Pane said yesterday that the level of mercury vapor in the building had been reduced from 10 micrograms per cubic meter to two micrograms. He said the level needs to be at one microgram per cubic meter before students can be permitted into the building.
The cleanup "is going quite well," Pane said, adding that the situation is not as serious as the mercury contamination in 2003 that resulted in a month-long closing of Ballou Senior High School in Southeast. At Ballou, a student broke into a chemistry lab and gave the mercury to friends, who spread it through the building.
"Because of the quick action of the principal, we minimized what could have been a Ballou or worse," Pane said.
School system officials released a report yesterday on another school that was closed temporarily for health reasons. The report concluded that $97,853 worth of repairs to the Walker-Jones Elementary School in Northwest corrected environmental problems that parents believed had sickened numerous students and staff members.
The report lists about five pages of repairs, including fixing the air-filtration system in numerous classrooms; replacing exhaust fans on the roof; replacing stained and missing ceiling tiles throughout the building; and scouring carpets and floors.
A Feb. 3 inspection detected elevated levels of fungus in parts of the building. Follow-up tests Feb. 19 and Feb. 22 showed acceptable levels of fungal spores, the report said.
"In closing, the latest report does not identify any concerns that would propose that the students and staff and Walker-Jones . . . are at risk," the study said.
Still, many parents apparently remained concerned about the condition of the building and were keeping their children out of school.
"Attendance was not good," Principal Ray Bledsoe said yesterday while overseeing dismissal. "It was very low, very low."
