The mothers of Eric Garner and Trayvon Martin want to snuff out a city proposal to outlaw menthol-flavored cigarettes, worrying that such a ban would fuel a menthol black market leading to more deadly “stop and frisk” encounters between police and young black people.

“We urge you to pay very close attention to the unintended effects of a ban on menthol cigarettes and what it would mean for communities of color,” reads the letter — sent to City Council Speaker Corey Johnson Wednesday by Gwendolyn Carr, whose son Eric was killed while being arrested for selling loose cigarettes in 2014, and Sybrina Fulton, whose son Trayvon was shot to death by a gung-ho Florida neighborhood-watch member in 2012.

“Both of us work with black youth throughout the country, including in New York City. We have seen the casualties of bad policies that have created unfortunate encounters with law enforcement,” they said.

They point out that 80 percent of black smokers puff on menthol cigs.

“When you ban a product sold mostly in black communities, you must consider the reality of what will happen to that very same over-represented community in the criminal justice system. … We are concerned that the ban will create a whole new market for loosies and re-introduce another version of stop and frisk in black, financially challenged communities where aggressive policing is a full reality and played out in national and local social media accounts every day,” they said.

“A ban will introduce or re-introduce many hard-to-employ young black New Yorkers to the criminal justice system. We do not want to take parents, sons and daughters out of households for small infractions that carry financial obligations.”

Carr and Fulton, who is running for office in Miami Dade County, spoke of a double racial standard.

“Banning menthol cigarettes means that cigarettes preferred by black New Yorkers would be illegal. Cigarettes preferred by non-black New Yorkers would be legal. Small violations can quickly escalate to consequential events. We strongly encourage you not to create a second stop-and-frisk through your actions,” they said.

The parents’ position parrots criticisms raised by Rev. Al Sharpton, whose National Action Network has received funding from tobacco giant RJ Reynolds — the maker of the nation’s top-selling menthol cigarette brand, Newport.

But the NAACP and other civil rights groups favor the menthol ban, saying the tobacco industry has long marketed the minty cigarettes to blacks and addicted them to smokes.

The Council is considering two bills — one to ban menthol-flavored cigs and another that would ban flavored vaping or e-cigs.

“Speaker Johnson is working diligently with stakeholders to best address this major problem of flavored nicotine products, which are attractive to young people and harming their health,” Johnson spokesperson Jennifer Fermino said when asked about the Carr-Fulton letter.