CHARLOTTE, N.C. -- Hazmat crews and authorities are investigating after the Mecklenburg Health Department was evacuated Monday morning.

A Health Department employee told NBC Charlotte they were evacuated after someone opened an envelope and white powder came out.

While there is concern on what the substance is, the employee said some believe it is laundry detergent.

Employees were seen standing outside the building located on Beatties Ford Road.

We have crews at the scene. Stay with WCNC.com for the latest.