Pittsburgh Police responded to the 500 block of Fairywood Street around 10:15 a.m. for a 9-1-1 call and Shotspotter Alert.
When Zone 6 officers arrived, they observed a City of Pittsburgh Environmental Services collection truck, which was struck by gunfire.
The two City employees performing their duties were not injured.
The shooter fled towards an unknown direction after firing two shots.
The investigation is ongoing.