Is your scented candle really non-toxic and all natural?

The Truth Behind “All Natural” and “Non-Toxic” Candle Labels

Browse any artisan candle shop, on Etsy, at a farmer’s market, or in a boutique gift store, and you will find the same reassuring vocabulary repeated everywhere: “all natural”, “clean burning”, “non-toxic”. These phrases appear on labels, in product descriptions, and in social media posts. They feel meaningful. They feel safe. And for the most part, the makers using them genuinely believe they are true.

The problem is that many scented candle makers base these claims on the fact that their candles are made from beeswax or plant-based waxes, such as soy or coconut. And that is where the reasoning stops. What these makers are not accounting for, and what their customers have no way of knowing, is what is actually inside the fragrance oil they are pouring into that wax.

To understand why this matters, we need to look at three things: what these marketing terms actually mean (or don’t mean), what fragrance oils are made of, and what happens when you light that candle and breathe the air around it. 

“All Natural” and “Non-Toxic” Candles: Unregulated, Undefined, and Unverified

Let’s start with the marketing language itself. In the United States, the terms “all natural,” “clean burning,” and “non-toxic” have no legal definition when applied to candles. No government agency, not the FDA, not the EPA, not the Consumer Product Safety Commission, requires a candle maker to prove any of these claims before printing them on a label. (In fact, there is no government oversight at all over small-scale candle makers.) They are marketing terms, not regulatory categories. Anyone can use them. No certification is required. No testing is mandated. No standard exists against which a candle must be measured to make these claims.

This is not a minor technicality. It means that a candle containing dozens of synthetic chemicals can be legally and freely marketed as “all natural.” A candle that releases formaldehyde, benzene, and ultrafine particles into your indoor air can be sold as “clean burning.” There is no one checking. There is no one who can make them stop.

When a small candle maker tells you their product is non-toxic, what they almost certainly mean is: I use what I believe is a natural wax, and I feel good about that. It is not a chemical claim. It is a values statement that is likely not based in reality.

What Are Fragrances Made Of? The Chemicals in Your Scented Candle

This is where things get complicated, and where the “natural wax = natural candle” logic completely breaks down.

While you might think that when a candle maker makes these claims about their scented candles that must mean they only use 100% natural essential oils. In actuality, very few pure essential oils function properly in candle, and therefore they are rarely used as the lone fragrance agent. Even if a candle is fragranced only with essential oil, there are almost no studies to show what chemicals are released when those oils are burned. 

Instead, most candle makers purchase fragrance mixes without knowing what is really in them. A single fragrance called something like “fresh linen” or “spun cotton” can contain a dozen to many dozen distinct chemical compounds. Some of these may be natural oils. However, many are synthetic molecules, including esters, aldehydes, alcohols, musks, and aromatic hydrocarbons, engineered in a laboratory to produce a desired scent. They are complex industrial chemical mixtures, and they are added to candles in concentrations that typically range from 6% to 12% of the total candle weight.

Fragrance manufacturers are not required to disclose the full composition of their blends to consumers. The word “fragrance” on a product label can legally conceal dozens of undisclosed individual chemicals. Even when safety data sheets are available, documents that list the hazardous components, they are written for industrial handlers, not for the people making candles or burning them in their living rooms.

To give you a concrete example: one of the most widely used candle-making fragrance suppliers has a rating system for how “clean” their fragrance mixes are. One of those fragrances, named “Spun Cotton” and given the highest possible rating for being “clean”, contains at least 27 disclosed hazardous chemical components. Note, that does not include the undisclosed chemicals. The list includes benzyl benzoate, hexyl cinnamaldehyde, OTNE (a synthetic musk), hydroxycitronellal, linalool, eugenol, coumarin, and more than twenty others, with names like “3-methyl-5-(2,2,3-trimethyl-1-cyclopent-3-enyl)pentan-2-ol”, spanning esters, aromatic aldehydes, terpene alcohols, and polycyclic compounds. This is a fragrance receiving the cleanest designation! It is reasonable to wonder what the less-clean ones look like.

Each of these chemicals has its own documented health profile. Several are established skin sensitizers and contact allergens. Some carry concerns about endocrine disruption. A few have been flagged by the EU’s Scientific Committee on Consumer Safety [1]. And crucially, the safety assessments that do exist were conducted on each chemical individually, not on the mixture as a whole, and not under conditions of combustion.

What Chemicals Does a Scented Candle Release When Burned?

Pouring fragrance oil into wax is one thing. Burning it is something else entirely.

When a candle burns, the fragrance chemicals in the wax do not simply evaporate into the air unchanged. They pass through a flame reaching temperatures of around 1,400°C at its tip. At those temperatures, complex organic molecules break apart, recombine, and transform into new compounds, many of which were not present in the original fragrance at all. Studies measuring candle emissions have detected benzene, toluene, formaldehyde, acetaldehyde, and polycyclic aromatic hydrocarbons (PAHs) in candle smoke, with scented candles producing higher volatile organic compounds (VOC) emissions than unscented ones [2].

Esters, and this particular fragrance contains many of them, thermally decompose into their constituent acids and alcohols, which then burn separately. Aromatic aldehydes like hexyl cinnamaldehyde fragment into benzaldehyde and smaller carbonyl species, which are known respiratory irritants. Benzaldehyde itself can further oxidize to produce phenol, phenyl radicals, and under incomplete combustion, a pathway toward benzene. Benzene is a Group 1 human carcinogen according to the International Agency for Research on Cancer [3].

The polycyclic musk compounds in fragrances are particularly concerning under combustion conditions. Their molecular architecture is structurally similar to known polycyclic aromatic hydrocarbons (PAHs) such as naphthalene, anthracene, and benzo[a]pyrene, and incomplete combustion of these structures is a known route to PAH generation.

Beyond what happens at the flame itself, the story continues in the room air. When fragrance products, whether directly emitted from the hot melted wax or via combustion, mix with the ozone that enters your home through normal ventilation, a cascade of secondary chemical reactions begins. Terpene-containing compounds, found in virtually every fragrance, react with ozone to produce formaldehyde, ultrafine particles, and secondary organic aerosol: new particles assembled in mid-air from the reaction products. Research has found that indoor terpene ozonolysis can produce peak particle concentrations approaching the U.S. EPA’s 24-hour guideline for particulate matter, with sub-10-nanometer particles that deposit efficiently deep in the lungs [4]. Another study confirmed that the use of terpenoid-containing products combined with indoor ozone generates formaldehyde and fine particulate matter at levels that may be substantial relative to health-based standards under some conditions [5].

Then there is the mixture problem, the issue that the entire fragrance safety system is not designed to address. The 27 chemicals in a fragrance like Spun Cotton were each assessed for safety individually, or at most in small groups. What happens when all 27 burn simultaneously, with their radical combustion intermediates interacting in the flame zone and producing novel compounds at their chemical interfaces? The honest answer is that nobody knows. That experiment has not been run. That question has not been answered. Toxicologists have noted that assumptions about chemical mixtures behaving additively may be premature, and that synergistic interactions between co-occurring chemicals should not be dismissed from risk assessment [6].

What is an all-natural candle? A non-toxic candle? A clean-burning candle?

The marketing terms attached to these candles, all natural, clean-burning, non-toxic, do not take into account the reality of fragrance chemistry. But they didn’t appear out of nowhere either. The term “non-toxic” in particular has a specific origin story. In 2009, researchers from South Carolina State University presented findings at an American Chemical Society meeting showing that paraffin candles emitted detectable levels of benzene and toluene. The study was never peer-reviewed, and it was funded by a USDA soy research program with a clear financial interest in the outcome. 

But the media translated the findings into a simple, alarming message: paraffin candles are toxic. Consumers began asking which candles were non-toxic, and the soy and beeswax candle industry was ready with an answer. The term exploded in marketing and has never left, despite actual published research showing little difference between emissions from paraffin and “natural” wax unscented candles.

The irony is that “non-toxic” has no legal or regulatory definition in the candle industry. No testing is required to use it. No standard must be met. It is a marketing response to a media panic built on a flawed, unpublished study, and it has been obscuring the real conversation about candle safety ever since. That is that fragranced candles generate far more toxic compounds than unscented candles made from any kind of purified wax. (For the full story on where this language came from, see: “The Non-Toxic Candle Myth: How One Study Changed an Industry.”)

These marketing terms were borrowed from the clean-living lexicon, applied to the wax, and allowed to stand in for the whole product. This is not necessarily malicious. Many small candle makers are simply unaware of the chemistry they are working with. Fragrance suppliers do not make it easy to know. The safety data sheets are dense, technical, and not written for the end consumer. And wax suppliers, themselves, continue to promote their waxes with these meaningless terms.

But unawareness is not the same as safety. And reassuring language is not the same as a safety assessment.

A candle maker may make the choice to use a naturally based wax over a synthetic one. But the moment a fragrance mixture is added the candle is no longer a simple, natural product. It becomes a vehicle for delivering a complex synthetic chemical mixture into your home.

How to Choose a Safer Candle

None of this means that burning a scented candle occasionally will harm you. For healthy adults in well-ventilated spaces, there is not enough evidence to support that conclusion. While candles, especially scented candles, can release toxic chemicals, they generally are not at levels considered to be hazardous to one's health. The concern is more nuanced: it is about chronic exposure, about vulnerable populations such as children, people with asthma, and people with fragrance sensitivities. It is especially about the gap between what the marketing implies, what the customer believes, and what the science actually says. What is clear from the scientific research is that unscented candles release fewer toxic chemicals than scented candles do.

If you are buying candles, look for makers who are transparent about what is in their candles. Be skeptical of labels that use “all natural” or “non-toxic” as selling points without any specifics to back them up. When burning candles, burn them as safely as possible (blog to come).

And if you are making candles, consider what you actually know about the fragrances you are adding, not just the wax you are pouring it into. The wax is the easy part. The fragrance is where the chemistry gets complicated. Don’t just add these marketing terms because everyone else is doing it. Our customers deserve honest descriptions of our products.

You deserve the joy of candlelight!