On Friday, the Centers for Disease Control and Prevention said more than 450 "possible cases" of vaping-related lung illnesses have been reported so far, both from nicotine and cannabis-containing vapes.

Four people have died, and there may be another death under investigation.

There are a variety of ways to consume marijuana and nicotine. Smoking and vaporizing are two of the most popular methods. It's unclear how many hospitalizations have been due to vaping nicotine versus marijuana.

When it comes to marijuana consumption, both methods come with risks, but smoking is thought to release more carcinogens from marijuana than vaping, Dr. Jeffrey Chen, the director of the UCLA Cannabis Research Initiative, told INSIDER.

Marijuana vaping poses other serious health risks because many of the pens use cannabis extracts or introduce toxins during their production process. Vaping can also get infrequent marijuana users higher than smoking.

Visit INSIDER's homepage for more.

On Friday, the Centers for Disease Control and Prevention said more than 450 "possible cases" of vaping-related lung illnesses have been reported since late June, both from nicotine and cannabis-containing vapes. Four people have died.

One death in Oregon involved a man who had previously used a cannabis vape pen he bought from a dispensary, according to state officials.

Additionally, one vape-related hospitalization reported in July involved an unnamed 26-year-old Wisconsin man who was put into a medically induced coma after vaping too much THC, the psychoactive component in cannabis. He had purchased the THC-containing vape cartridge off the street, INSIDER reported.

The man's brother, Patrick DeGrave, told USA Today that his brother sustained serious lung damage from vaping.

"He was not breathing on his own at all yesterday. His heart was weak. They weren't sure he was going to make it," he said.

As more states legalize recreational and medicinal marijuana and more adverse health effects are reported, questions concerning the health risks associated with the substance and its various consumption methods are on the rise.

For example, what are the effects of vaporizing marijuana versus smoking it? Although limited research currently exists, there is some data and anecdotal evidence that can offer a look into the health risks, or lack thereof, associated with these two popular methods.

Smoking marijuana releases tar and carcinogens into the body

Smoking marijuana releases carcinogens — substances or environmental factors that may lead to cancer — into the body. That's because cannabis, the plant marijuana is derived from, is like any other plant, according to Dr. Jeffrey Chen, the director of the UCLA Cannabis Research Initiative. "When you combust any plant, you're creating significantly more carcinogens," Chen said.

Some people who switched from smoking weed to vaping it have noticed improvements in their lung health. AP Photo/Esteban Felix

Smoking marijuana also releases tar into the body. In fact, the American Lung Association noted that marijuana smokers have "greater exposure per breath to tar," than cigarette smokers, since they typically inhale for longer.

Read more: 15 celebrities who have talked about smoking weed



That said, Chen told INSIDER that some people who switched from smoking weed to vaping it have noticed improvements in their lung health and experience less bronchitis. In fact, a 2007 study in the Harm Reduction Journal found that vaporizing marijuana can reduce respiratory issues caused by smoking marijuana through a pipe, bong, or other combustible method. More research on the long-term effects of weed vaporizers still must be done, though, to ascertain this claim.

Your choice of vape method determines safety

There is one major caveat when it comes to the benefits of vaping marijuana, and it comes down to whether you use a traditional vaporizer or a vape pen. While smoking the substance through a pipe, bong, or other methods may release more marijuana-based toxins than vaping, pens can also introduce dangerous carcinogens to a person's body, Chen explained.

That's because the current vape pens being sold in smoke shops and dispensaries aren't the same thing as traditional vaporizers. To use a traditional vaporizer, a person puts dried marijuana flower into the vape's chamber and then heats it as if it were in a convection oven. The resulting vapor from the heated flower is what gets a person high.

Vape pens might expose users to harmful toxins

Vape pens typically use marijuana extracts in the form of liquid-filled cartridges that are attached to the pen and then inhaled. This means smokers are inhaling concentrated contaminants and carcinogens that go directly into the bloodstream.

A carrier agent is sometimes added to a marijuana extract so it heats and burns more smoothly through the vape pen. Eduardo Munoz/Reuters

These contaminants are introduced to a vape pen when the weed is grown and the extract is created and packaged. According to Chen, pesticides, fertilizers, and even heavy metals may touch a cannabis plant in the growing process. While these toxins can also affect a person smoking marijuana through a pipe or bong, vape pen users could be exposed to an especially concentrated form.

Additionally, the process used to turn marijuana into an extract uses special solvents that aren't always safe for the body, Chen said. "Butane or hexane are bad and might remain in the extract," he told INSIDER. "They try to remove them, but sometimes there is some left over [in the extract]."

A carrier agent may also be added to a marijuana extract so it heats and burns more smoothly through the vape pen. These carrier agents, like glycerin, also contain carcinogens and, according to Chec, "at high temperatures, these contaminants can turn into even more harmful things."

Research has shown that vaporizers get infrequent users higher than if they smoke marijuana

In addition to vaping's effects on a person's long term health, this marijuana consumption method may create dangerous short-term effects for certain people.

Read more: Scientists are starting to learn how e-cigs like the Juul can affect your health — and the results are troubling

A 2018 study from Johns Hopkins Medicine, for example, found that infrequent cannabis users may get higher from vaping weed than from smoking it. "What our study suggests is that some people who use cannabis infrequently need to be careful about how much cannabis they use with a vaporizer, and they should not drive, even within several hours after use," Ryan Vandrey, the study's lead author, said in a press release.

With combustible smoking methods, users get a general idea of how much marijuana they are consuming. While some vape pens signal when a user has reached a specific dose, more often than not a person can't see the physical marijuana and may therefore vape without realizing how much marijuana they actually consume. As a result, they may get higher than they would from combustible methods. A small 2018 study in JAMA found this to be true. After researchers had some people use vapes and others smoke marijuana, they discovered the vape users felt higher and some even vomited or hallucinated after vape use.

What's more, infrequent users who vape could experience greater feelings of anxiety, nausea, vomiting, and hallucinations, the researchers found. Since vape use could impair users and put them and others in dangerous situations, people should evaluate their circumstances before using one of these devices and consuming marijuana in general.