It was caught on surveillance video at 12:25 a.m. Tuesday at the BP gas station at 2200 West Allegheny Avenue.
Police say two men and a woman walked into the store with a fire extinguisher and sprayed the clerk in the cashier's booth.
Once the booth was filled with powder from the extinguisher, the suspects stole items from the shelves and fled.
Police released the following descriptions of the suspects:
Suspect #1: Black male, 16-20 years old, 5'6"-5'8", wearing a black wool hat, white t-shirt, red shorts. This suspect was wearing a backpack on his front which contained the fire extinguisher.
Suspect #2: Black male, 16-20 years old, 5'9",-5'11", wearing a black t-shirt and blue jeans.
Suspect #3: Black female, 16-20 years old, 5'7"-5'9", wearing a black shirt and purple shorts.
Anyone with information is asked to contact Philadelphia Police at 215-686-TIPS (8477), text a tip to PPD TIP (773847) or through PhillyPolice.com.