UPDATE: The substance has turned out to be flour at the Peoples Natural Gas North Shore location.
Original story:
Pittsburgh Hazmat and EMS Crews are on the North Shore after an employee at a business opened an envelope that contained an unknown substance.
It happened Morning on the 300 block of North Shore Drive.
Around 300 employees are sheltering in place while the substance is tested.
There are no reported illnesses or injury at this time.
This is a developing story.