The legalization of marijuana is steadily moving — or perhaps creeping — forward in the United States.

This has some experts concerned that the public health battles fought against Big Tobacco are about to be repeated — this time against the burgeoning Big Marijuana industry.

“Given the lessons learned from the 20th-century rise of another legal addictive substance, tobacco, we believe that such an industry could transform marijuana and its effects on public health,” wrote the authors of a 2014 editorial in the New England Journal of Medicine.

Cigarette Additives

Naturally, people on both sides of the marijuana legalization debate are quick to draw comparisons between the two substances. Many of these arguments are seemingly at odds with each other.

When you look deeper into the nature of marijuana products and cigarettes themselves, what shakes out is a torrent of similarities and differences that start to cut through the smoky haze surrounding this debate.

From Farm Crop to Industrial Powerhouse

Over the past century, industrialization has changed tobacco from essentially an agricultural crop to a much-altered product rolling off the assembly line in near-perfect uniformity. This product development was coupled with the rise of cigarette marketing.

Right now the marijuana industry is still in its infancy. Health officials, though, see legalization as an invitation for companies to follow in the well-proven footsteps of the tobacco industry.

“I’m concerned that we’re going to create a new tobacco epidemic,” Stanton Glantz, a professor of medicine at the University of California, San Francisco, told Healthline. “With the advent of mass marketing, combined with consumer product engineering, I think it’s going to be a public health disaster.”

This may mean following a similar path through well-funded research and development.

In the 1880s, manufactured cigarettes accounted for only 1 percent of the tobacco used in the United States. By the 1950s, this figure had increased to around 80 percent.

But the move toward uniform machine-rolled cigarettes didn’t just make cigarettes more aesthetically appealing. It also increased the health risks.

Additives or No Additives, It’s Still Harmful

Cigarettes — including secondhand smoke — are bad for your health.

For a sense of how bad, you need only to look at the Food and Drug Administration’s list of 93 harmful and potentially harmful substances that can be found in cigarettes and cigarette smoke. This list, however, contains a mere fraction of the 5,000 known chemical components of cigarette smoke.

The FDA’s list contains cancer-causing agents (such as arsenic and formaldehyde), compounds that can harm babies inside the womb (most notably mercury), chemicals that can damage the respiratory or cardiovascular system (such as ammonia and acrylamide), and the highly addictive compound nicotine.

Some of these occur naturally in tobacco. Others are added to cigarettes to make them easier to smoke or to help the smoke flow more deeply into the lungs. Many of the agents also increase the toxicity of cigarettes and their smoke.

A 2011 paper by Glantz and colleagues in PLoS Medicine — based on tobacco industry documents — found that additives in cigarettes increased the amount of toxins in cigarette smoke.

Even if you remove all the additives, you’re left with a product that’s harmful when smoked.

“When you add additives to the cigarettes it does make the cigarettes a little bit more toxic,” said Glantz, “but I think the most toxic thing in cigarettes is the tobacco.”

Even cigarettes marketed as “additive-free” or “natural” carry health risks, which led the FDA to recently issue a warning against three manufacturers for using that kind of marketing. The FDA requires companies to provide scientific evidence to support such claims.

Following the Footsteps of Big Tobacco

Some supporters of marijuana legalization say that pot is not as bad for you as cigarettes. The way Glantz sees it, though, the two products have a lot in common.

“If you look at marijuana smoke, it’s not terribly different from cigarette smoke. In some ways it’s worse, and in some ways it’s not as bad, but overall, it’s smoke,” he said. “So you would expect long-term exposure to marijuana smoke to have very similar effects to long-term exposure to tobacco smoke.”

Smoking cigarettes has already been linked to an increased risk of lung cancer, heart disease, stroke, and other types of cancer.

To date, research on the health effects of marijuana smoke is mixed. Some studies found that marijuana smoke is as bad as cigarette smoke. Others have found the opposite.

One problem with marijuana research is that people who smoke pot often smoke cigarettes, so it’s hard to separate the health effects of each. And marijuana is still illegal in most of the United States, so studies are difficult to conduct.

Over time that may change, as marijuana replaces cigarettes in popularity and legalization continues to spread.

“Twenty years from now we’ll probably have a cohort of pure marijuana users,” said Glantz, “and we’ll have a pretty good idea of exactly what diseases it’s causing.”

One of his fears, though, is that along the way, Big Marijuana will adopt the practices of its older and highly experienced sibling.

Glantz said a marijuana joint or another marijuana product can become more toxic if it is engineered to maximize addictive potential the way cigarettes are. That would include the use of additives, what kind of paper is used, how porous the paper is, what additives are put in the paper, and how densely the leaf is cut and packed.

“They’re going to become much more dangerous,” he said.