DENVER (CBS4)– A new law aims to stop so-called “coal rollers” from intentionally blasting black smoke into the air.

Some diesel truck owners are modifying their engines and disabling pollution controls so they can intentionally blast black smoke. It’s called “rolling coal” and now a new law in Colorado aims to stop it.

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(credit: YouTube)

(credit: YouTube)

Coal rollers, as they call themselves, have posted videos online of souped-up diesels spewing clouds of black soot, making it impossible to see, and in some cases, hard to breathe.

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Many of them do it to flaunt environmental regulations.

(credit: YouTube)

“It’s harassing behavior, it’s bullying and it’s a new law that we had to put into effect because there weren’t any,” said Rep. Joann Ginal, a Democrat representing Fort Collins.

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Violators face a $100 fine. Fort Collins is one of the places where it’s become increasingly popular, especially along College Avenue.