Authorities tell Action News that three girls, two of them sisters, ordered food at the location at 58th and Baltimore.
[Ads /]
Before leaving, the girls brought up a problem with their order with a female worker at the drive-thru window.
That's when an argument began.
A friend who doesn't want to be identified said the employee first told the women to come back when the employee got off work so they could fight.
They tell Action News they just wanted their food.
Soon the argument turned violent.
"She got a metal container and was digging inside the fryer that's been on for 24 hours a day - that's a 24 hour store - that grease was hot," the witness said.
The witness says three times the worker threw containers of grease, one right after another. A fellow employee at first unsuccessfully tried to stop her.
[Ads /]
The hot grease splashed on the car and went through the window, hitting one of the women on the thigh and forearm.
"We were arguing back and forth, but that doesn't give her the right to throw grease on us. She wasn't hit, she wasn't threatened. We didn't do anything to her," said the witness.
Police were called and the employee was later arrested, charged with aggravated and simple assault.
"We could have been seriously injured. We have a family member right now that's in the hospital for burns," said the witness.
The victim who was burned has since been treated and released from the hospital.
A statement released Saturday afternoon from a spokesperson for Checkers read, "The franchise is taking this incident very seriously, and the manager involved is no longer with the company. That behavior was completely unacceptable and does not represent the values of the hundreds of Checkers employees who serve our Philadelphia guests every day. The franchise is cooperating fully with the police in their investigation."