Updated 3:23 p.m.
Authorities have given the all-clear at Mt. SAC. The evacuation order has been lifted.
The university is aware of a potential emergency situation at Mt. SAC and Walnut High School. The potential incident is isolated to Mt. SAC and Walnut High.
There is no impact to the Cal Poly Pomona campus. University Police are closely monitoring the situation.
In the event of an emergency at Cal Poly Pomona, the university will send messages via the Safety Alert System. Emergency procedures and safety information can be found on our Safety and Emergency Information website.