Ricin, a potentially deadly poison, was found in a University of Texas dormitory Thursday by a student who reported the substance to school police officers.
The dorm was sanitized, and the substance was sent to a laboratory for testing and came back positive for ricin Friday night. University officials said they had not yet determined where it came from.
A "small amount" of UT students living in Moore-Hill dormitory were exposed to the substance, UT police spokeswoman Rhonda Weldon said.
The students are now at an undisclosed location and are in contact with the FBI. They are not showing any symptoms, officials said. Other students living in Moore-Hill were being moved to Jester dormitory Friday night, Weldon said.
There is no threat to the university suspected, but an investigation is under way, Weldon said.
The substance found in Moore-Hill was a chunky powder and exposure was limited due to the humid conditions, Dr. Adolfo Valadez of the Austin health department said.
"We were very concerned as soon as we heard about the positive testing late this evening," said Dr. Theresa Spalding of UT Health Services. "But everything was packed away and tested in an orderly manner."