Weber State University police cleared the already all-but-empty Engineering Technology Building on Thursday afternoon when an unknown powder was found on a desk.
WSU spokeswoman Allison Hess said the Ogden City Metro Hazmat Unit was testing the "white, powdery substance" spotted in the second-floor classroom about 12:30 p.m. It eventually turned out to be a non-toxic plaster.
No injuries were reported. About 20 staff and students were evacuated pending results of the testing.
"It has been a very light day in that building," Hess said, noting that the campus was in the last day of finals week and "everything had been finished up in that building" when the discovery was made.
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