Spokeswoman Corinne Geller said an employee found the substance Wednesday afternoon while opening mail in the criminal justice information services division. It was in an envelope with a sex-offender registration form, but there was no written threat.
Geller said the ventilation system was shut down on that floor, which was evacuated. Hazardous-materials teams determined that there wasn't any immediate danger, and transported the powder to the state laboratory.
The employee, supervisor and two others who were near the substance were quarantined and monitored. Geller said they haven't shown any symptoms of illness.