I. The Statutory Framework

The Clean Air Act of 1970, as amended in 1977 and 1990, is the comprehensive federal statute governing air pollution in the United States. It operates through a system of nationally uniform standards, state implementation plans, and federally enforceable permits. The Act regulates two categories of pollutants: the six “criteria pollutants” for which the EPA sets National Ambient Air Quality Standards under Section 109, and the 187 “hazardous air pollutants” listed under Section 112(b) for which the EPA sets technology-based emission standards.¹

The criteria pollutants are particulate matter (PM), ground-level ozone, carbon monoxide, sulfur dioxide, nitrogen dioxide, and lead. The hazardous air pollutants include benzene, formaldehyde, toluene, and multiple polycyclic aromatic hydrocarbons. A paraffin candle emits substances from both lists.²

The Act’s regulatory machinery depends on the definition of “stationary source.” Section 111(a)(3), codified at 42 U.S.C. § 7411(a)(3), provides the operative text: “The term ‘stationary source’ means any building, structure, facility, or installation which emits or may emit any air pollutant.”³ The statute does not define “installation.” It does not require that the installation be industrial. It does not require that the installation be large. It does not require that the installation operate continuously. It requires only that the installation emit, or may emit, any air pollutant.

A candle is an installation. It is installed in a holder, on a shelf, on a table, or in a fixture. It does not move during operation. It emits air pollutants during operation. The statute does not specify a minimum thermal output. It does not specify a minimum emission rate. It does not specify a minimum combustion temperature. It specifies only that the thing emit, or may emit, any air pollutant.

We submit that a candle emits air pollutants. We submit that this is not a controversial proposition. We submit that it is, in fact, the reason people open windows after burning them.

II. The Combustion Chemistry

A paraffin candle is a solid-fuel combustion device. Paraffin wax is a petroleum-derived hydrocarbon, a mixture of straight-chain alkanes with carbon numbers typically ranging from C20 to C40. It is refined from the same crude oil feedstock that produces gasoline, diesel fuel, and heating oil. The American Chemical Society classifies paraffin wax as a petroleum product. The EPA classifies petroleum combustion as a regulated activity. Candle manufacturers classify their product as a “home fragrance solution.”⁴

When a candle is lit, the wick draws liquid wax upward through capillary action into the combustion zone. The wax vaporizes and undergoes thermal cracking, producing smaller hydrocarbon fragments that combust in the flame envelope. The flame tip reaches temperatures exceeding 1,400°C. Under ideal conditions, complete combustion would yield only carbon dioxide and water vapor. Under the conditions that prevail on every coffee table in America, combustion is not complete.⁵

Incomplete combustion of paraffin wax produces a complex emission profile that includes fine and ultrafine particulate matter, soot (elemental carbon), carbon monoxide, volatile organic compounds including benzene and toluene, semi-volatile organic compounds, aldehydes including formaldehyde and acetaldehyde, and polycyclic aromatic hydrocarbons including naphthalene, acenaphthylene, and fluorene. A 2013 study published in Environmental Science: Processes & Impacts established a standardized emission testing protocol for measuring benzene and formaldehyde emissions from candles, confirming that both carcinogenic compounds are reliably produced during normal candle combustion.⁶

The EPA regulates the combustion of petroleum-derived hydrocarbons in furnaces. It regulates the combustion of petroleum-derived hydrocarbons in boilers. It regulates the combustion of petroleum-derived hydrocarbons in internal combustion engines, industrial process heaters, and waste incinerators. It does not regulate the combustion of petroleum-derived hydrocarbons in glass jars with decorative labels that say “Coastal Breeze” on them.

III. The Particulate Matter Violation

Particulate matter is the most extensively regulated criteria pollutant in the Clean Air Act. The EPA sets National Ambient Air Quality Standards for two size fractions: PM10 (particles with an aerodynamic diameter of 10 micrometers or less) and PM2.5 (particles with an aerodynamic diameter of 2.5 micrometers or less). PM2.5 is the fraction of greater health concern because these particles penetrate deep into the lungs and enter the bloodstream.⁷

On February 7, 2024, the EPA promulgated a revised primary annual PM2.5 National Ambient Air Quality Standard, strengthening it from 12.0 micrograms per cubic meter to 9.0 micrograms per cubic meter. The agency retained the existing 24-hour PM2.5 standard at 35 micrograms per cubic meter. The agency stated that particle pollution “is one of the most dangerous forms of air pollution” and that “an extensive body of science links it to a range of serious and sometimes deadly illnesses.”⁸

The peer-reviewed literature on candle emissions is unambiguous. A 2012 study by Noonan et al. measured indoor PM2.5 concentrations of 70 micrograms per cubic meter during candle burning. Assimakopoulos et al. (2018) documented 36 micrograms per cubic meter. Wyss et al. (2016) reported a mean hourly concentration of 20.3 micrograms per cubic meter. Jedrychowski et al. (2006) measured 48-hour mean personal PM2.5 exposure during candle burning at 45.6 micrograms per cubic meter.⁹

A Norwegian study of indoor combustion sources found that PM2.5 levels were 15 micrograms per cubic meter higher when candles were burned, a statistically significant contribution that persisted after controlling for all other indoor sources including wood stoves, cooking, and cleaning.¹⁰

Under stressed burning conditions—which include an untrimmed wick, a drafty room, or the simultaneous burning of multiple candles, conditions that describe approximately every living room in December—PM2.5 concentrations can reach 2,010 micrograms per cubic meter, as documented in a 2025 study published in Scientific Reports. This is 223 times the annual NAAQS. It is 57 times the 24-hour NAAQS. It is a concentration at which the EPA would evacuate a building if the source were industrial rather than aromatic.¹¹

The agency set the annual standard at 9.0 micrograms per cubic meter to protect, in its own words, “millions of Americans from harmful and costly health impacts, such as heart attacks and premature death.” It has not extended this protection to the Americans who light a candle.

IV. The Hazardous Air Pollutants

Section 112(b) of the Clean Air Act, codified at 42 U.S.C. § 7412(b), lists 187 hazardous air pollutants for which the EPA is required to establish emission standards. Among them are benzene, formaldehyde, toluene, naphthalene, and multiple other polycyclic aromatic hydrocarbons.¹²

Benzene is classified by the International Agency for Research on Cancer as a Group 1 carcinogen, meaning there is sufficient evidence that it causes cancer in humans. The EPA classifies it as a known human carcinogen. The Clean Air Act specifically identifies benzene as a hazardous air pollutant. Candle combustion produces benzene. A study cited by the EPA’s own HERO database documented benzene emissions from scented candles during normal indoor use, with concentrations increasing during combustion and persisting for an hour afterward.¹³

Formaldehyde is classified by IARC as a Group 1 carcinogen. The EPA classifies it as a probable human carcinogen. Candle combustion produces formaldehyde. Measurements confirmed that formaldehyde emissions increased during candle burning, and the same HERO-cited study noted that emissions were attributable to both primary release and secondary atmospheric reactions catalyzed by candle combustion products.¹⁴

Toluene is a hazardous air pollutant under Section 112(b). A 2022 editorial in Pharmacological Research noted that petroleum is the source of 95 percent of the chemicals used in synthetic perfumes and scented candles, and that “candle waxes are still coloured using toluene derivatives and benzidine-based dyes, which have been associated with urothelial cancer development.”¹⁵

Under Section 112, the EPA is required to promulgate National Emission Standards for Hazardous Air Pollutants—known as NESHAP—for “major sources” and “area sources” that emit these substances. A major source is any stationary source that emits 10 tons per year of any single HAP or 25 tons per year of any combination. An area source is any stationary source that is not a major source.¹⁶ The EPA has issued NESHAP for dry cleaners, gasoline dispensing facilities, plating operations, and auto body refinishing shops. These are area sources. A candle is an area source. The EPA has issued NESHAP for zero candles.

V. The Polycyclic Aromatic Hydrocarbons

Polycyclic aromatic hydrocarbons, or PAHs, are a class of organic compounds consisting of two or more fused aromatic rings. Many are carcinogenic. Seven are listed as hazardous air pollutants under Section 112(b). The EPA regulates PAH emissions from coke oven batteries under 40 CFR Part 63, Subpart L. It regulates PAH emissions from aluminum production under Subpart LL. It does not regulate PAH emissions from candles under any subpart.

A 2025 study published in Atmosphere compared particulate emissions from synthetic (paraffin) and natural (soy, beeswax) candles in a residential setting. Synthetic candles produced nearly twice the particle concentrations of natural candles across all measured size fractions, a difference that was statistically significant at p < 0.001. The researchers concluded that “paraffin-based candles are stronger sources of 0.3–10 μm particles under the tested conditions” and that the results were “commonly associated with soot formation and incomplete combustion.”¹⁷

Derudi et al. (2013) measured total PAH emission factors ranging from 26.6 to 152 nanograms per gram of burned candle, with variation attributable to wax composition and oil content. A 2024 study reported total PAH emission factors from scented candles of 17.6 to 72.9 nanograms per gram of wax consumed, with benzo(a)pyrene equivalent factors of 0.097 to 0.596 nanograms per gram.¹⁸

A pillar candle burns at a rate of 4.4 to 7.3 grams per hour, as measured in controlled laboratory conditions by Rasmussen, Wang, et al. (2021).¹⁹ At the midpoint burn rate and midpoint PAH emission factor, a single three-hour candle session produces approximately 800 nanograms of polycyclic aromatic hydrocarbons. This is a small number. Multiply it by the 130 million households that burn candles. Multiply it by the three evenings per week the National Candle Association reports as average usage frequency. The aggregate is no longer small. It has never been measured. It has never been reported. It has never appeared in any emission inventory compiled by the EPA or any state agency.

VI. The New Source Performance Standards

Section 111 of the Clean Air Act directs the EPA to establish New Source Performance Standards for categories of stationary sources that “cause, or contribute significantly to, air pollution which may reasonably be anticipated to endanger public health or welfare.” As of 2013, the EPA had promulgated approximately ninety NSPS, codified at 40 CFR Part 60, Subparts A through QQQQ.²⁰

The regulated categories are instructive. Subpart D covers fossil-fuel-fired steam generators. Subpart Da covers electric utility steam generating units. Subpart Db covers industrial-commercial-institutional steam generating units. Subpart Dc covers small industrial-commercial-institutional steam generating units. Subpart E covers incinerators. Subpart Ea covers municipal waste combustors. Subpart Eb covers large municipal waste combustors. Subpart Ec covers hospital/medical/infectious waste incinerators. Subpart CCCC covers commercial and industrial solid waste incineration units.²¹

Every one of these categories involves the combustion of carbon-based fuel in a stationary installation. Every one of them produces particulate matter, carbon monoxide, volatile organic compounds, and, depending on the fuel, hazardous air pollutants. Every one of them is subject to emission limits, monitoring requirements, reporting obligations, and compliance deadlines.

A candle involves the combustion of carbon-based fuel in a stationary installation. It produces particulate matter, carbon monoxide, volatile organic compounds, and hazardous air pollutants. It is subject to nothing.

The EPA has issued NSPS for facilities that burn coal. It has issued NSPS for facilities that burn oil. It has issued NSPS for facilities that burn natural gas. It has issued NSPS for facilities that burn municipal solid waste, hospital waste, commercial waste, industrial waste, and sewage sludge. It has not issued NSPS for facilities that burn paraffin wax infused with synthetic lavender fragrance oil. The omission is not explained in any Federal Register notice. It is not addressed in any rulemaking preamble. It is not the subject of any regulatory determination. The agency simply proceeded as though the combustion of petroleum-derived hydrocarbons in residential settings does not occur.

VII. The Fire Paradox

The federal government is not unaware that candles exist. The National Fire Protection Association, whose standards are incorporated by reference into federal regulations, maintains detailed statistics on candle-related fires. During the five-year period 2014–2018, U.S. fire departments responded to an average of 7,610 home structure fires per year that were started by candles. These fires caused an annual average of 81 civilian deaths, 677 civilian injuries, and $278 million in direct property damage.²²

The Consumer Product Safety Commission regulates candle fire safety under 16 CFR Part 1500 and the Federal Hazardous Substances Act. It has issued mandatory standards for candle flame height and secondary ignition. It maintains an injury database. It conducts recalls. It understands that a candle is a combustion device that presents hazards to human health and safety.

The EPA also understands that combustion devices present hazards to human health and safety. This understanding is the foundation of approximately ninety NSPS, the entire Title V operating permit program, the National Emission Standards for Hazardous Air Pollutants, and the regulatory apparatus that employs thousands of engineers, attorneys, and compliance specialists across ten regional offices.

The CPSC regulates candles because they produce fire. The EPA does not regulate candles because they produce emissions. The fire and the emissions come from the same flame. The two agencies have divided the flame between them and each regulates only its half.

VIII. The Scale of the Noncompliance

The National Candle Association and independent market research report that candles are used in approximately seven out of ten U.S. households. The Census Bureau reports approximately 131.2 million occupied housing units in the United States as of 2023. Seventy percent of 131.2 million is approximately 91.8 million households that burn candles.²³

U.S. retail sales of candles are estimated at approximately $2 billion annually, with more than 350 commercial manufacturers and scores of small craft producers operating across the country. The average consumer purchases four to five candles per year. The majority of consumers burn candles one to three times per week, with half burning one to two candles simultaneously.²⁴

Each of these candle-burning sessions constitutes the operation of a stationary source that emits criteria pollutants and hazardous air pollutants without a New Source Performance Standard, without a National Emission Standard for Hazardous Air Pollutants, without a Title V operating permit, without a state implementation plan provision, and without a single line in any emission inventory.

The EPA’s own plain-language guide to the Clean Air Act, published on its website, defines a stationary source as “a place or object from which pollutants are released and which does not move around” and provides the following examples: “power plants, gas stations, incinerators, houses etc.”²⁵ The agency listed houses. A candle is in a house. The candle is in the house that the agency listed as an example of a stationary source. The agency has regulated neither the house nor the candle.

IX. The Regulatory Asymmetry

Consider the regulatory treatment of two combustion devices operating simultaneously in a single American home on a winter evening.

In the basement, a natural gas furnace rated at 100,000 BTU burns methane through a controlled burner assembly. This device is subject to DOE efficiency standards under 42 U.S.C. § 6295, NSPS requirements if it exceeds applicable thresholds, and state and local permitting under delegated Clean Air Act authority. Its manufacturer must certify compliance with emission limits. Its installer must verify proper venting. Its combustion products are routed through a flue to the exterior of the building and disperse into the ambient air, where they are monitored by state and federal ambient air quality networks.

On the dining room table, a paraffin candle burns petroleum-derived hydrocarbon wax through an uncontrolled wick. This device is subject to no DOE efficiency standard, no NSPS, and no state or local air quality permit. Its manufacturer must certify nothing about its emissions. Its installer—the person who placed it on the table—has no licensing requirement. Its combustion products are not routed to the exterior. They are released directly into the breathing zone of the home’s occupants at concentrations that peer-reviewed studies have documented at two to eight times the National Ambient Air Quality Standard for PM2.5, a standard the EPA established specifically because particle pollution causes “heart attacks and premature death.”²⁶

The furnace combustion products go outside, where they are diluted by the atmosphere and monitored by regulatory networks. The candle combustion products stay inside, where they are concentrated by the building envelope and monitored by nobody. The more dangerous exposure pathway is the unregulated one.

X. Conclusion

The evidence requires no interpretive leap. Section 111(a)(3) of the Clean Air Act defines a stationary source as any installation which emits or may emit any air pollutant. A candle is an installation. It emits air pollutants. The peer-reviewed literature documents those emissions with quantitative precision: PM2.5 at 36 to 70 micrograms per cubic meter under normal burning conditions, benzene and formaldehyde as confirmed carcinogenic byproducts of incomplete hydrocarbon combustion, polycyclic aromatic hydrocarbons at emission factors the EPA regulates when they originate from coke ovens but ignores when they originate from a three-wick soy-blend jar candle labeled “Autumn Harvest.”

The National Ambient Air Quality Standard for PM2.5, strengthened in February 2024 to 9.0 micrograms per cubic meter, is exceeded by a factor of four to eight during ordinary candle use and by a factor of two hundred during stressed burning conditions. The agency that set this standard has not acknowledged that the most common residential combustion source in America routinely exceeds it.

The EPA has issued approximately ninety New Source Performance Standards for categories of stationary sources. It has regulated the combustion of petroleum in refineries, in boilers, in generators, in incinerators, and in engines. It has not regulated the combustion of petroleum in the device Americans use most frequently to burn petroleum indoors. Seven out of ten households do it. They do it one to three times per week. They do it with the windows closed and the furnace running and the building envelope sealed to the specifications of the Department of Energy’s own weatherization standards.

The Consumer Product Safety Commission understood that a candle is a combustion device and regulated it for fire risk. The EPA has not understood—or has understood and declined to act upon the understanding—that the same combustion device is also an emission source.

The flame does not distinguish between its hazards. It produces heat and it produces emissions in the same exothermic reaction. One federal agency regulates the heat. Another federal agency regulates emissions from every other combustion source in the country. Between them, the emission from the candle falls through a regulatory gap that is approximately one inch wide and four thousand degrees hot.

Ninety-two million households light candles in the United States. Each one operates an unpermitted stationary combustion source that emits criteria pollutants and hazardous air pollutants into the breathing zone of its occupants. The aggregate has never been inventoried. The cumulative health impact has never been assessed. The regulatory framework has never been applied.

The Clean Air Act was enacted to protect public health from air pollution. Candles produce air pollution. The Act covers stationary sources. Candles are stationary sources. The Act requires the EPA to issue standards for source categories that endanger public health. Candles endanger public health. The chain of statutory logic contains no break, no ambiguity, and no exception.

The candle industry sells two billion dollars of unregulated combustion devices per year. The EPA has issued zero rules, zero guidance documents, zero regulatory determinations, and zero notices of proposed rulemaking. It has not even asked the question.

We are asking it now.

Ergo.