CHRISTIANSBURG, VA., FEB. 2 -- About 1,300 workers were sent home today from the Radford arsenal because of an unidentified greenish substance that oozed into the New River from Crab Creek, a spokeswoman said.

The substance did not immediately kill any fish, but its appearance prompted officials from the arsenal and the towns of Christiansburg and Blacksburg, about 225 miles southwest of Washington, to stop taking water from the New River.

"It's not emanating from us," Radford arsenal spokeswoman Frances Selnow said. "It's not our slime. It's upstream of us, and the substance was traveling to the New River."

Christiansburg Town Manager John Lemley said the greenish substance came through the Christiansburg sewer system, but other officials were not sure where it came from or what it was. He also disputed the contention that it was slimy.

"I don't know where they came up with the green slime part," Lemley said. "There is a green substance. There's nothing slimy about it."

Lemley said that by late afternoon, three laboratories had been unable to determine what the substance was.

Lemley said Christiansburg, Blacksburg and the arsenal stopped drawing water from the New River while authorities were investigating. He said Christiansburg had about 3 million gallons stored elsewhere, enough to last two days, and said town officials were not calling for conservation.

Kip Foster, a technical services supervisor with the state Water Control Board in Roanoke, said area residents would be wise to conserve water until authorities identified the substance.