LEWISTON, Maine (AP) — A spokeswoman says five workers were decontaminated after an envelope containing white powder was opened at a state office in Lewiston, Maine.

The substance was later determined to be harmless, but not before the Judicial Branch Violation Bureau was evacuated Monday morning and a hazardous materials unit called.

The office receives all of the mail statewide for people paying civil and traffic fines. It also houses a call center for routine calls for the court system.

Mary Ann Lynch, spokesman for Maine courts, says about 20 people work in the building and that five who came into contact with the powder were decontaminated.

She says the powder turned out to be prescription diuretic, or water pill. She says the case will be prosecuted by police and postal inspectors.