If you buy cigarettes anywhere in America, the pack will include a dire warning that “smoking causes lung cancer, heart disease, emphysema.” 

Smoking pot may do the same — but only three states of 24 where recreational cannabis is legal require similar warnings about cannabis products on their packaging.

New York warns against smoking weed when breast-feeding, but Oregon doesn’t.

Massachusetts warns against driving under the influence of cannabis, but Missouri doesn’t.

That wild variation is important to consider after President Donald Trump, notwithstanding the fact that he’s a teetotaler, took a major step toward making cannabis more easily available across the United States.

Last week, he reclassified pot as a Schedule 3 drug under the Controlled Substances Act, making it officially less dangerous than under its previous Schedule 1 designation, which it shared with heroin.

It will be easier for cannabis distributors to do business in the 41 states where medical marijuana is legal and 24 where recreational pot is for sale.

But while Trump moves the nation toward a national cannabis market, there’s no single health warning required for cannabis products, unlike another drug Americans smoke: tobacco.

Thanks to a weird legal environment — pot is still illegal on the federal level but each state makes its own call on it — the variation is striking.

The differences range from warnings on driving while impaired, risks to mental health and even the importance of keeping cannabis gummies away from children.

If we’re to have a national market for legal cannabis products — and we’re getting close — we need a thorough, federally required, prominent warning label that states can use for all weed products, even if they’re not federally sanctioned.

A mandated warning would require congressional action but that shouldn’t stand in the way of Food and Drug Administration-suggested language.

There’s plenty to include. The Centers for Disease Control and Prevention warn that cannabis users are “more likely to develop psychosis and long lasting mental disorders, including schizophrenia.”

That applies especially to those “who start using cannabis at an earlier age and use cannabis products more frequently.”

Then there’s the risk of traffic accidents: Because of its effects on “coordination, memory and judgment,” cannabis use, again per the CDC, “can impair important skills for safe driving.”

One might think that every state in which cannabis is legally for sale would want to warn consumers of these sorts of risks.

But only two states — New Jersey and Montana — require warnings about the risk of psychosis.

Almost all states require warnings about the risk for drivers, but three jurisdictions (Missouri, Minnesota and DC) don’t.

Only four states — Illinois, New Mexico, New York and Washington — require warnings about the physical effects of smoking itself; i.e., lung cancer.

Illinois, however, doesn’t bother to warn cannabis buyers to keep their gummies out of the reach of children.

There’s already a basis for what a federal cannabis warning might include.

The National Institutes of Health have, helpfully, developed a list of 12 suggested warning messages that states should consider including on cannabis products — including about its risks to mental-health, breast-feeding and driving.

Yet no state requires all 12 NIH warnings. Only Connecticut, Colorado and New York require as many as eight; Washington, DC, requires only two.

Warnings should be prominent since it’s easy to ignore fine print or quickly spoken warnings in TV and radio ads.

But per the American Journal of Public Health, there’s “substantial evidence” not only “of an association between cannabis use and the development of mental health problems” but also that “warning labels can be highly efficacious.”

It only makes sense, moreover, for those warnings to be standardized across the country, as per arguments last week at the Supreme Court about the need for a federal — not state-by-state — cancer warning about the week-killer Roundup.

States have an incentive to be lax about warnings. Their lawmakers are lured by the prospect of “sin” tax revenue that cannabis sales can bring and have championed legalization.

In 2024, New York Gov. Kathy Hochul boasted about pot sales: New York’s cannabis industry “has reached a historic milestone of more than $1 billion in retail sales,” making the state “a national leader in cannabis equity and innovation.”

States rely on tax revenue from the sale of tobacco and alcohol, but governors would never boast of boosting sales of hard liquor or cigarettes.

The US has rushed toward cannabis legalization — including the use of “medical marijuana” before any FDA review of its safety and efficacy. 

The least we can do is to warn the public about pot’s potential dangers.