11 Chemicals That Shouldn’t Be in Your CBD Vape Oil

List of 11 chemicals in CBD vape oils that you should avoid

Vaping is popular, but like smoking, it' has its cons. Here's what you should look out for when buying vape oil. Image Credit: By Doug Shutter on Shutterstock

Less than a decade ago, few Americans had ever heard of vaping. As people began searching for a safer alternative to traditional cigarettes, though, vaping skyrocketed in popularity. The advantages were obvious: no smell, more flavors, and fewer carcinogens. Now you could have all the “coolness” of smoking without the crippling future health problems, and an industry was born.

Since then, vaping has become so ubiquitous that flight attendants have to warn passengers against taking puffs of their electronic cigarettes in airplane bathrooms. Still, as this once-mysterious phenomenon becomes increasingly mainstream, people are beginning to realize that it’s not exactly a risk-free substitute for smoking tobacco cigarettes.

The “dangers of vaping” shouldn’t be overblown — in general, you’re still better off reaching for a cartridge of CBD vape oil than a pack of Marlboros. But all vape oils aren’t created equal, and it can be hard for the beginner to tell which oil is the best to use, and which ones are a lot less safe than they claim to be.

It’s not an impossible task, though. The trick is having a basic understanding of the chemicals involved, and which ones you really need to steer clear of. Here’s a list of 11 chemicals in vape oil that should make you seriously reconsider your potential purchase (and a few others that should give you pause).

Chemicals to Avoid

Before we begin, a brief note — to protect yourself from inhaling harmful chemicals when you vape, there’s more to consider than just the oil you buy. You should also do some research into the vape pen itself, as the heating coils of some models have been shown to leak harmful heavy metals.


According to a 2018 study from researchers at Johns Hopkins, the vapor produced by vape pens and other vaporizing devices contained “significant amounts of toxic metals, including lead.” This was likely caused by faulty heating coils, but lead can also make its way directly into vape oils — especially hemp-derived CBD oils, since hemp is a bioaccumulator (i.e. it easily absorbs the chemicals present in the soil where it grows).

One of the most common uses of lead is for the production of battery acid. It is a highly toxic chemical which can be very harmful to the body. Lead can cause damage to vital organs like the heart and kidneys of adults, and cause severe developmental problems in children (Exhibit A: the ongoing humanitarian disaster in Flint, Michigan, where lead-tainted water has left thousands of children with birth defects and learning disabilities).

While secondhand smoke is generally considered to be a non-issue when it comes to vaping, the presence of lead in vape oil can make it highly toxic not only to the user, but also anyone in their vicinity — especially children.

It’s unlikely that most vape oil manufacturers would be dumb enough to put lead on their list of ingredients, but if the hemp from which it’s derived was grown in a place with lax environmental protections — such as China or certain parts of the U.S. — you should probably steer clear anyway.

2. Nickel

Like lead, nickel is a carcinogen, which means that inhaling it increases the risk of developing cancers. Because of this, nickel can be found on the Hazardous Substances List as a highly dangerous alloy, and its use is regulated by the Occupational Hazard Safety Association.

What are those uses, exactly? Nickel is primarily used to create stainless steel and other corrosion-resistant alloys, making it a vital material for manufacturing jet engines, power generators, and industrial cookware.

If that sounds like something you wouldn’t want in your vape oil, you’re absolutely correct. Sadly, that Johns Hopkins study found that nickel was also present in many vape oils (though again, the main culprit here may be the heating coil of vape devices).

The presence of nickel may be even more worrisome, however, as it’s the most serious carcinogen when inhaled.

3. Acetaldehyde

A volatile, colorless liquid that is created through the oxidation of ethanol, acetaldehyde is actually a natural chemical that can be found — in low levels — in fruits, cheese, and milk. However, don’t let its “natural” branding fool you into thinking it’s harmless: it may be a dangerous carcinogen for people who are exposed to it frequently or at high volumes.

If you’re wondering why acetaldehyde would be in your vape oil in the first place, the answer is: for flavor. In the past it’s been used to sweeten pastries, soft drinks, and desserts, though this is beginning to change as people become more aware of its potential health risks.

If you see a vape oil that looks cheap and sweet, check to see if it has acetaldehyde — and if it does, don’t buy it.

4. Acrolein

This is a chemical that you may not have heard of before. Primarily used to create acrylic acid, acrolein is also used to kill microorganisms in irrigation canals, oil wells, and water treatment ponds. Another use? “[Controlling] slime in papermaking,” which really makes it sound like something you’d want to put in your body.

Even in very low concentrations, acrolein is highly toxic when inhaled. Its vapors irritate the mucus membranes of your nose, throat, and lungs, and long-term exposure can cause severe damage to your respiratory system. Acrolein is also commonly found in cigarette smoke and car exhaust.

In the context of vaping, studies detailed in the ACS Omega journal have shown that acrolein is one of the most serious carcinogens found in vape oils. As with several of the examples above, it’s believed that the heating coils of vape devices may be the primary cause of contamination.

5. Benzene

Benzene is a widely used chemical in common household products. You will probably find it in your plastics, detergents, paints, pesticides, and glues (among other things). Produced naturally by forest fires and volcanoes, it’s also a major component of gasoline.

As another carcinogenic chemical, benzene can increase the risk of cancer in general and leukemia in particular. It is also believed to corrode the bone marrow and cause severe damage to red blood cells in the body. These effects are caused not just by inhaling the chemical, but also by exposure to it in the air. This makes it another substance, like lead, which isn’t just harmful to the vaper but also to the people they vape around.

While benzene itself isn’t typically an ingredient in vape oils, several related chemicals (like benzoic acid or benzaldehyde) are common additives. Studies from Portland State University have shown that when vape devices are operated at high power, benzene can form as a result — so in this case, both the device and the oil share the blame.

6. Cadmium

A silvery white metal, cadmium is naturally found in the earth’s crust and is extracted from other metals such as lead and zinc. Because it occurs naturally in the earth, it is emitted when fossil fuels such as coal are burned, and is found in some foods including potatoes, grains, and leafy vegetables.

Inhaling high levels of cadmium can be fatal, but even exposure to lower levels of the chemical can lead to lung and kidney damage. This is a very powerful, toxic substance that has been found in vape oils and should definitely be avoided.

7. Diethylene Glycol

Diethylene glycol is a colorless, odorless, and highly poisonous compound that may be one of the most infamously toxic chemicals in America. In 1937, 34 children and 71 adults lost their lives in “the Elixir Tragedy” after consuming a cure-all potion called Elixir Sulfanilamide, of which the primary component was diethylene glycol.

The public health tragedy — or, more accurately, the ensuing backlash — gave birth to the Food and Drug Administration (FDA) as we know it today. When an investigation revealed that diethylene glycol was the primary cause of death of The Elixir Tragedy’s victims, new regulations were put into place in the form of the Food, Drug, and Cosmetics Act of 1938, which gave the FDA much more oversight to monitor the development of new drugs.

In 2009, the FDA warned about the presence of diethylene glycol and other cancer-causing chemicals in e-cigarettes, though it was unclear how prevalent it was in different brands. In this case, as in several others above, faulty heating coils seemed to greatly exacerbate the problem.

8. Formaldehyde

Yes, the same stuff that your creepy high school biology teacher used to preserve frogs in his “specimen jars.” While formaldehyde does have many practical uses — it’s found in everything from shampoos to cosmetics to, gulp, food preservatives — it’s also a well-known carcinogen. According to the American Cancer Society, “Exposure to relatively high amounts of formaldehyde in medical and occupational settings has been linked to some types of cancer in humans.”

The National Cancer Institute, which has published multiple studies of people whose jobs entail substantial exposure to formaldehyde (such as funeral home embalmers), says that its findings suggest “these individuals are at an increased risk of leukemia and brain cancer compared with the general population.”

Needless to say, formaldehyde doesn’t belong in vape oils. It could, quite literally, cause mutations — researchers have found that vapers who used oils containing formaldehyde suffered damage to the DNA in the cells of their mouths.

9. Isoprene

At first glance, isoprene might seem out of place on this list. Unlike lead or formaldehyde, it’s commonly produced by plants — including trees like eucalyptus, poplars, and oaks. Scientists think these plants produce isoprene in order to protect themselves against excessive heat, almost like a natural sunscreen.

This might sound nice, but the impact of isoprene on living things with legs is much less encouraging.

When tested on rats and mice, the effects of isoprene were highly toxic. Not only did the test subjects experience organ damage and increased risk of cancer, but they also appeared to display significant decreases in male fertility. Human studies are still in progress, but the U.S. Department of Health and Human Services has said that it’s “reasonably anticipated to be a human carcinogen.”

10 N-Nitrosonornicotine

N-Nitrosonornicotine is a chemical that’s produced during the curing and processing of smoking tobacco and tobacco products. An oily, yellow liquid, it has has a mildly sweet smell and flavor.

It’s classified in the United States as a Group 1 carcinogen, meaning it has been found to be extremely carcinogenic. Despite this, N-Nitrosonornicotine has been used in some vape oils and flavored e-liquids.

Why? It’s not entirely clear, other than the fact that it’s harder to remove than manufacturers would prefer. In any case, it’s best avoided.

11. Polycyclic Aromatic Hydrocarbons

Polycyclic aromatic hydrocarbons are chemicals that are formed whenever something is burned. They’re found in crude oil, coal, and gasoline. As you might expect, they’re not the most environmentally-friendly substances — once released, they can linger in the air, soil, and water for months or years.

There are over 100 different kinds of polycyclic aromatic hydrocarbons, some of which have been found in vaping oils. These chemicals have a variety of severe negative effects on the body. For example, they have been found to have immunosuppressive properties (i.e. they can prevent the immune system from functioning properly) as well as mutagenic and carcinogenic effects.

For vapers, the main risk of polycyclic aromatic hydrocarbons is posed, once again, by the heating coil.

Chemicals to Approach With Caution

Propylene glycol
This chemical is one of the two most common “bases” for vape oils today. It’s also one of the most common chemicals you can find in commercial products in general. Despite the eyebrow-raising name (and a whole lot of controversy), the FDA considers it safe for use as a food additive. A byproduct of petroleum, propylene glycol is found in everything from eye drops to fog machine vapor to novelty ice cream treats.

In vape oils, the main purpose of propylene glycol is to produce the “smoke” that makes the experience so satisfying. It’s also sweet but colorless and odorless, which allows it to blend well with other flavors.

When it comes to its safety profile, the jury is still out. While it’s been deemed safe for oral consumption, that doesn’t necessarily mean it’s safe for inhalation as well. Some findings reported in physiological reports, show that vaporized propylene glycol doesn’t pose much of a safety hazard in typical situations, while others suggest that vape oils containing propylene glycol could “have unsuspected effects on gene expression of the molecular clock that are to be taken seriously, especially considering the fundamental role of the circadian rhythm in health and disease.”

Vegetable glycerin
This chemical is the other most common base for vape oils. It’s a sugar alcohol made from plant oils such as soybean, palm, or coconut oils. Believed to have been discovered as many as 2,000 years ago, it first rose to popularity in the 1800s, when it became an important ingredient in … dynamite.

Like propylene glycol, vegetable glycerin is prized in vape oils for its ability to produce thick, rich clouds of smoke (even thicker and richer, in fact). And again, it is sweet, colorless, and odorless, providing a malleable foundation for a wide range of flavors.

The similarities don’t stop there: vegetable glycerin has also been the subject of intense scientific scrutiny in recent years. According to some researchers, vaping vegetable glycerin can alter the lungs in ways that “are likely not harmless and may have clinical implications for the development of chronic lung disease.” Other studies have stated that vegetable glycerin has “very limited biological effects with no signs of toxicity.”

Sarah Tyrrell
Sarah Tyrrell
Sarah Tyrrell is a health, wellness, and lifestyle writer based in Ireland whose work has appeared in The Irish Times and The Independent, among others. In 2017, she founded the lifestyle brand “Self Love and Sarah” to promote healthy self image and body positivity for women.

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