Secondhand marijuana smoke carries the same risks as secondhand cigarette smoke, according to new research presented by the AHA. (Brennan Linsley/AP)

Preliminary research presented at the American Heart Association’s Scientific Sessions 2014, which shows that breathing secondhand marijuana smoke might damage your heart and blood vessels as much as secondhand cigarette smoke, could impact the trajectory of what, until now, has been primarily a grassroots marijuana industry. The AHA findings may not significantly curtail the enormous momentum that the marijuana legalization movement now has nationwide — where Alaska, Oregon and Washington, D.C. approved legalizing measures on Nov. 4 — but it could have important implications for the future structure of the industry by introducing new risks for smaller businesses.

Until now, the marijuana industry has favored the entry of tiny, entrepreneurial businesses. This is the result, to a large degree, of regulatory guidelines that determine who can sell, and how much. There are other factors as well: the unwillingness of cautious financial institutions to fund new marijuana start-ups, the bans on marketing marijuana and the logistical difficulties in distributing products to a wider audience. Add in the patchwork regulatory regime that varies by state and the inability of any business to acquire true scale by crossing over state lines and it means companies simply can’t scale the way they might in other industries. As a result, though, we’re seeing rapid innovation in everything from new products to new business models.

But what happens once there are real legal and health risks involved as well?

The findings of the secondhand marijuana smoke researchers suggest that these risks are real and worrisome. What the researchers found was that blood vessel function in lab rats dropped 70 percent after 30 minutes of exposure to secondhand marijuana smoke. Even when the marijuana contained no THC — the active ingredient in marijuana that produces the “high” — blood vessel function was still impaired. Reduced blood vessel function may raise the chances of developing atherosclerosis and could lead to a heart attack, say researchers.

In short, marijuana and cigarette smoke are chemically and physically alike, aside from their active ingredients. That’s worrisome because, according to the U.S. Surgeon General, secondhand tobacco smoke causes about 34,000 premature deaths from heart disease each year in the United States among nonsmokers. “Most people know secondhand cigarette smoke is bad for you, but many don’t realize that secondhand marijuana smoke may also be harmful,” said Matthew Springer, Ph.D., senior author of the study and cardiovascular researcher and associate professor of medicine at the University of California-San Francisco’s Cardiology Division.

And that’s not all, says the American Heart Association. Despite the ability to legally use marijuana in some places and in some situations, there are still many unanswered questions about how the drug may affect the heart or brain. One study from New Zealand presented at the 2013 American Stroke Association’s International Stroke Conference found that marijuana use actually doubled the risk of stroke among young people. Using marijuana in conjunction with other drugs, such as tobacco, may also have unknown consequences. And, says the AHA, there have yet to be any comprehensive tests on edible marijuana — a fast growing, tricky-to-regulate product that may carry its own share of health risks.

Not only could the marijuana industry lose some of its “harmless” and “beneficial” image that it has acquired in the popular culture, it may catalyze the secular trend toward bigger companies better capable of commercializing specific products and responding to regulatory and health risks. That’s what we’ve seen with Big Pharma and Big Tobacco. And that’s why we might see with Big Marijuana as well.

The logic is simple: Big companies handle big risks better than smaller companies. As the cost of doing business increases and as the risk exposure within an industry changes, this has an impact on the structure of the industry. Assuming at some point that smaller marijuana businesses must comply with new rules and regulations concerning secondhand smoke – even if it’s only labeling their products with new warnings — all of this carries a very real cost.

Denver’s “Green Mile” boasts the world’s tightest concentration of marijuana retailers. Small mom-and-pop stores, though, could one day give way to larger retail giants better able to deal with the industry’s health risks. (Kristen Wyatt/AP)

Right now, there’s a “Gold Rush” mentality in states like Colorado, where everybody has a new idea for a new marijuana business. Denver’s “green mile” is full of people with ideas for pot businesses the same way that Silicon Valley is full of people with ideas for new mobile apps. Anyone who dares to call out the risks and hazards of marijuana legalization — such as the UN drug czar, who recently spoke out about U.S. marijuana legalization measures — is basically labeled a fuddy-duddy.

All of that could change, however, if the narrative starts to shift in favor of outlining the potential health risks of marijuana use. We could start to see factors favoring the emergence of larger, more cautious companies and the decline of smaller, more experimental companies. Suddenly, the amount of innovation we’re currently seeing in the marijuana industry could change.

This is an important point. We’re innovating so fast in some areas of the marijuana industry that we’re barely even stopping to see what the long-term implications might be. We’re so focused on the potential economic benefits of a potential $40 billion annual business that we haven’t focused enough on the potential health risks. That’s where the latest research presented by the American Heart Association, which provides a template for measuring the effects of secondhand marijuana smoke, might throw a wrench into the works of the marijuana legalization movement. At the very least, it will inspire greater debate about what types of companies we’ll see next in the marijuana industry.