DeWeese claimed the worker asked if he was "one of those black lives matter protesters/rioters?" — prompting him to start recording.
"So you sell gasoline here, right?" he asks, but the attendant keeps saying no, pointing him to another garage two blocks to the left.
When DeWeese asks again, the worker replies "Here, you wanna call the police? We'll do that," striding to the phone.
"I'm trying to understand how come I can't get gas," DeWeese asks. "You're not explaining to me why you are refusing to sell me gasoline."
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"You don't watch the news?" the attendant asks. "Well there's dumpster fires. They get a can of gasoline and they start the fires."
Dumbfounded, DeWeese asks: "So are you picking and choosing who to sell gasoline to?"
"That's right," he replies.
Despite explaining that he needs the gas for his lawnmower at his home a couple of blocks away, the attendant continues to refuse, telling a third man who asked why: "He's got an illegal gasoline container" — even though the can certainly appears to be a regular gas canister.
"There's dumpster fires all over town... you heard nothing about protesting?"
When DeWeese asks what that has to do with him, the attendant replies: "I'm just doing my part to keep down the fires in town."
DeWeese asks if he's not worried about damaging his business, but he just scoffs: "Like we can make some money on a gallon of gas."
In the end, Deweese finally calls him out: "They are refusing to sell me gasoline because he is judging me and stereotyping me, saying I'll start riots and fires," he tells the camera.
"I'll drop it: he's being racist."
"I'll put it in your car, I'll put it in your lawn mower, but I wont put it in a jug to go," the attendant insists.
Portland has been a hotbed of violent clashes between police and protesters for the past number of weeks.
On Thursday Governor Kate Brown announced federal troops would begin a "phased withdrawal" from the downtown area, promising state and local police would help secure the federal properties that have been a focal point of angry protesters.