A University of Texas student found a substance in a roll of quarters that tested positive for ricin, a potentially deadly poison, but more tests were needed, officials said Saturday.

The 19-year-old student, who said she unwrapped the powder in her dormitory room Thursday, and her roommate were checked at a hospital for potential exposure to the poison, although neither had any symptoms, officials said.

"I guess you can say I was just weirded out," said Kelly Heinbaugh, a freshman kinesiology major. "It seemed out of place ... I figured I'd rather be safe than sorry."

Because people with ricin poisoning develop symptoms within a few hours of exposure, university officials were confident all the students would be fine, said Dr. Theresa Spalding with university student health services.

Symptoms can include anything from difficulty breathing, fever, cough, nausea and sweating to severe vomiting and dehydration.

Preliminary tests by state health officials showed the substance to be ricin or a substance close to it, spokesman Doug McBride said. FBI spokesman Rene Salinas said federal investigators would conduct further tests.

"There is nothing to lead us to believe that it is in fact a terrorist act," he said. "There's no link to any terrorism."

Officials said the roll of quarters had been in the students' room at the Moore-Hill dormitory for several months.

The dormitory was sanitized and inspected, and students were cleared to return, the university said.

"We feel like we have taken every precaution possible to assure the safety and health of our students," university spokeswoman Rhonda Weldon said.

Ricin is extracted from castor beans and can be added to food or water, injected or sprayed as an aerosol. It can be in the form of a powder, mist, pellet, or it can be dissolved in water or weak acid.