Charcoal briquettes release a mix of toxic compounds when they burn, including carbon monoxide, fine particulate matter, and cancer-linked chemicals called polycyclic aromatic hydrocarbons (PAHs). The risks range from acute carbon monoxide poisoning in enclosed spaces to long-term concerns about airborne pollutants and contaminants that settle into grilled food. How dangerous they are depends heavily on where and how often you use them, but the combustion chemistry is genuinely concerning, and briquettes consistently perform worse than both lump charcoal and gas grills in emissions studies.
Carbon Monoxide Is the Most Immediate Threat
The single deadliest risk from charcoal briquettes is carbon monoxide. CO is colorless and odorless, and briquettes produce a lot of it. A study measuring CO output from various charcoal products found that the average 24-hour CO concentration from all samples reached about 37 parts per million, roughly six times higher than the World Health Organization’s air quality guideline of 6.34 ppm for a 24-hour period.1PubMed. Evaluating the properties that affect the quality of the charcoal product, determining the limits of toxic emissions during combustion, and studying their impact on human health That number comes from an open-air or semi-open measurement context. In a closed room, a garage, or a tent, CO levels climb far higher and far faster.
A systematic review of charcoal-briquette-related deaths found that most fatal cases occurred in enclosed or poorly ventilated spaces, with victims showing blood carboxyhemoglobin levels above 30%, a threshold strongly linked to death.2Indonesian Journal of Pharmaceutical Education. Carbon Monoxide as a Toxic Agent in Charcoal Briquette-Related Deaths: A Systematic Literature Review These fatalities include both accidental poisonings (grilling indoors, using briquettes for heat) and intentional deaths. The review concluded that charcoal briquette combustion in confined spaces remains a significant and preventable cause of CO-related mortality. The practical takeaway is straightforward: never burn briquettes indoors, in a garage with the door partway open, inside a tent, or in any space that does not have full outdoor ventilation.
What Burning Briquettes Release Into the Air
Beyond CO, the smoke from charcoal briquettes carries a cocktail of pollutants. A broad review of charcoal combustion emissions identified CO, COâ‚‚, nitrogen oxides, particulate matter, PAHs, volatile organic compounds (VOCs), and trace metals as components of the smoke plume.3Environmental Advances. Charcoal-based products combustion: Emission profiles, health exposure, and mitigation strategies Briquettes tend to be dirtier than lump charcoal on a per-kilogram basis. One study found briquettes had CO emission factors above 250 grams per kilogram of fuel, VOC emissions above 1.5 grams per kilogram, and total suspended particulate emissions above 7.5 grams per kilogram, all higher than lump charcoal.4Air Quality, Atmosphere & Health. Grilling and air pollution: how charcoal quality affects emissions
The particulate matter is especially striking. During the lighting phase alone, charcoal combustion can push PM10 levels (particles small enough to inhale deeply) to 28 to 104 times above background levels. When fatty foods like salmon or sardines hit the grill, those numbers jump even higher, reaching over 130-fold above background in some cases. Nearly all of that particulate, about 99%, falls into the PM2.5 category, meaning the particles are fine enough to penetrate deep into your lungs.5Atmospheric Environment. Outdoor charcoal grilling: Particulate and gas-phase emissions, organic speciation and ecotoxicological assessment
The PAH story is particularly unfavorable for briquettes. Researchers comparing fuel types found that total PAH concentrations in the air around charcoal briquette grills reached about 21.5 micrograms per cubic meter, compared to undetectable levels around gas grills. The daily PAH exposure for a grill operator working with briquettes, adjusted for toxicity equivalence, was roughly 10,000 times higher than it would be working a gas grill.6PubMed. Inhalation Exposure to PM-Bound Polycyclic Aromatic Hydrocarbons Released from Barbecue Grills Powered by Gas, Lump Charcoal, and Charcoal Briquettes Another study calculating incremental lifetime cancer risk found that both lump charcoal and briquette grilling pushed the risk above the threshold generally considered unacceptable, with professional cooks facing the highest calculated exposure.7PubMed. Inhalation risk to PAHs and BTEX during barbecuing: The role of fuel/food type and route of exposure
What Is Actually Inside a Briquette
Part of the reason briquettes emit more pollutants than lump charcoal comes down to what they are made of. Lump charcoal is just carbonized wood. Briquettes, on the other hand, are manufactured products: charcoal fines are bound together with various additives, compressed under pressure, and shaped into uniform blocks. Common binders include starch, flour, lignosulfonate, and sometimes synthetic adhesives like polyvinyl acetate.8Cleaner Engineering and Technology. Mechanochemical and molecular analysis of organic binders in charcoal briquetting for enhanced cold mechanical strength – Section: 3. Results and discussion Beyond binders, briquettes can also contain fillers, mineral matter, and sometimes coal or coke to extend burn time.
A microscopy study of 74 commercially available charcoal products from seven countries found a range of contaminants in briquettes, including coal, coke, metal fragments, rust, plastics, glues, and synthetic resins. The majority of the products analyzed failed the European quality standard for charcoal briquettes, which allows less than 1% contaminants. Some products contained up to about 27% impurities, and the amount of contaminants correlated with higher particulate matter and CO/COâ‚‚ emissions during burning.9PubMed. Environmental implications of the quality of charcoal briquettes and lump charcoal used for grilling
Trace metals are another concern. Briquetted products contain substantially higher concentrations of elements like aluminum, arsenic, copper, nickel, and cadmium than lump charcoal, likely because of the additives and secondary materials used in manufacturing. When briquettes burn and leave ash, the concentrations of these metals increase even further as organic material burns away. A study simulating human digestion found that arsenic and copper in briquette ash were among the most bioaccessible metals, meaning they are readily absorbed by the body. The researchers flagged aluminum and arsenic as the trace elements of greatest health concern from barbecuing.10Journal of Hazardous Materials. Concentrations and bioaccessibilities of trace elements in barbecue charcoals
How Grilling Contaminates the Food Itself
The health concern with charcoal grilling is not limited to what you breathe. It also involves what ends up in the food. When meat cooks at high temperatures over an open flame, two classes of potentially harmful compounds form: polycyclic aromatic hydrocarbons (PAHs) and heterocyclic amines (HCAs). PAHs form in two ways. First, fat and juices drip from the meat onto the hot coals and incomplete combustion generates PAH-laden smoke that rises and deposits onto the food.11PubMed Central. The Presence of Polycyclic Aromatis Hydrocarbons (PAHs) in Grilled Beef, Chicken and Fish by Considering Dietary Exposure and Risk Assessment Second, direct pyrolysis of the food’s own nutrients at high temperature creates additional PAHs on the food surface.12Food Chemistry. Effects of meat preheating and wrapping on the levels of polycyclic aromatic hydrocarbons in charcoal-grilled meat
HCAs are produced by the interaction of creatine, sugars, and amino acids in muscle tissue at high cooking temperatures.13Journal of Food Protection. Effects of Cooking Methods and Tea Marinades on the Formation of Heterocyclic Amines and BaP in Grilled Drumsticks Both PAHs and HCAs have been classified as mutagenic and in some cases carcinogenic. The type of fuel matters here too: one study found PAH concentrations in the air above charcoal-briquette grills were over 250 times higher than above gas grills when grilling meat.7PubMed. Inhalation risk to PAHs and BTEX during barbecuing: The role of fuel/food type and route of exposure And while high-temperature charcoal grilling raises both PAH and HCA formation in the food, charcoal type and grilling conditions both play a role.14PubMed. Effect of charcoal types and grilling conditions on formation of heterocyclic aromatic amines (HAs) and polycyclic aromatic hydrocarbons (PAHs) in grilled muscle foods
What Happens to People Exposed Regularly
For someone who grills a few times a summer, the chronic health risks are relatively small. The exposure duration is short, the setting is outdoors, and the dose is limited. But for people who work around charcoal grills daily, the picture changes. A study of grill workers in Vientiane, Laos, found elevated respiratory symptoms among workers, with contributing factors including indoor grilling, more years of grill work, and exposure to intense smoke.15Journal of Air Pollution and Health. Grill workers and air pollution health effects from charcoal combustion in Vientiane capital
Research on charcoal-grill restaurant workers found significantly more wheezing and shortness of breath compared to control subjects. In one study, roughly half of restaurant workers reported wheezing, compared to none among controls.16Frontiers In Public Health. An analysis of occupational exposure to particulate matter and erythrocyte morphological abnormalities among charcoal-grill restaurant workers Work in charcoal production also carries respiratory risk. A study of charcoal workers in Namibia found that those with the highest cumulative dust exposure were roughly twice as likely to report chronic cough and phlegm production, with even higher odds for episodes combining both symptoms.17PubMed Central. Respiratory health effects of occupational exposure to charcoal dust in Namibia
These occupational findings offer a useful lens for the home griller. The effects tracked in workers are dose-dependent: more exposure, more symptoms. A weekend barbecue is orders of magnitude less exposure than eight hours a day beside a grill for years. But the underlying biology is the same. The smoke is irritating and carcinogenic in a dose-dependent way, and standing directly in a thick plume while flipping burgers is not nothing, even outdoors.
Lighter Fluid Adds Its Own Problems
Many people start their briquettes with a squirt of lighter fluid, and the fluid itself brings a separate set of toxicological concerns. Most lighter fluids are composed of C9 to C14 aliphatic hydrocarbons, mainly alkanes and alkenes, with some products containing aromatic constituents up to about 2% of total volume. Safety data sheets classify most of them under a hazard statement meaning they can cause lung damage if swallowed and may be fatal if they enter the airways. Small amounts of volatile C5 and C6 compounds are also typically present as ignition accelerants.18PubMed Central. Environmental Sustainability of Lighter Fluids
In practice, if you let lighter fluid burn off completely before cooking, minimal residue reaches the food. The concern is more about the combustion products added to the smoke plume during the lighting phase, and the environmental load of repeated use. A chimney starter, which uses newspaper or a fire starter cube and convection to ignite charcoal, avoids lighter fluid entirely. Electric starters are another option. Both eliminate the hydrocarbon-solvent component from the equation.
Practical Ways to Reduce Your Exposure
If you grill with briquettes and do not plan to switch to gas, there are evidence-based steps that meaningfully lower the toxic load.
- Use a drip tray: One of the biggest PAH sources is fat dripping onto hot coals and flaring back up as contaminated smoke. A study comparing grilling methods found that the highest PAH levels in chicken came from charcoal grilling without a tray, while the use of a tray or indirect heat substantially lowered contamination.19PubMed Central. Effects of Different Marinades and Types of Grills on Polycyclic Aromatic Hydrocarbon Content in Grilled Chicken Breast Tenderloins
- Marinate your meat: The same study found that certain marinades acted as barriers against PAH absorption, likely because phenolic compounds in marinades scavenge free radicals involved in PAH formation.19PubMed Central. Effects of Different Marinades and Types of Grills on Polycyclic Aromatic Hydrocarbon Content in Grilled Chicken Breast Tenderloins
- Use higher-carbonization charcoal: Research has shown that charcoal prepared using higher carbonization temperatures produces less PAH-laden smoke during grilling. Preheating briquettes before cooking (letting them ash over fully rather than grilling over still-flaming coals) also reduces PAH transfer.20PubMed. Reduction of the polycyclic aromatic hydrocarbon (PAH) content of charcoal smoke during grilling by charcoal preparation using high carbonisation and a preheating step
- Stay upwind: Inhalation exposure depends on your position relative to the smoke plume. Standing directly downwind, breathing smoke for an extended cook, is a very different exposure than standing upwind and stepping in briefly to flip food.
- Skip the lighter fluid: A chimney starter eliminates the hydrocarbon accelerant from the smoke entirely.
- Choose leaner cuts: Fattier foods generate far more particulate matter. The PM spike from grilling sardines or salmon was many times larger than from leaner meats in emissions testing.5Atmospheric Environment. Outdoor charcoal grilling: Particulate and gas-phase emissions, organic speciation and ecotoxicological assessment
None of these steps eliminate the risk entirely. They reduce it. If you grill a handful of times per year, the residual risk after taking these precautions is probably negligible for your long-term health. If you grill weekly or work near a grill daily, the cumulative benefit of combining several of these measures is more meaningful.
What to Do With the Ash
Most people dump briquette ash in the trash or scatter it in the yard without a second thought, but the ash is not inert. When briquettes burn, the organic material combusts and trace metals concentrate in what remains. A study of wood briquette ash found that heavy metal concentrations were significantly higher after combustion than in the original fuel, making some ash samples unsuitable for agricultural use.21PubMed. Quantification of heavy metal(oid)s in wood briquettes and residual ash Research on household ash disposal in communities relying on solid fuels found that ash dumped on private land or surrounding areas contained extremely elevated heavy metal levels, with some samples showing lead concentrations nearly 50 times higher than national soil quality standards.22Advances in Engineering Research. Unseen Threats: Soil Pollution from Household Ash in Nalaikh’s Ger Districts
Charcoal briquette ash is particularly concerning because, as noted earlier, briquettes start with higher concentrations of metals and additives than lump charcoal does. The combustion process concentrates those metals further. Scattering briquette ash in your garden, compost pile, or near a vegetable bed is a poor idea. The safest disposal method is to let ash cool completely, bag it, and put it in household waste. If you use lump hardwood charcoal with no additives, the ash is cleaner and sometimes used as a mild soil amendment, but even then, moderation is wise because of natural metal accumulation during burning.
Briquettes Versus Lump Charcoal Versus Gas
Across nearly every measure that matters for health, briquettes come in last among common grilling fuels. They emit more CO, more VOCs, and more particulate per kilogram than lump charcoal.4Air Quality, Atmosphere & Health. Grilling and air pollution: how charcoal quality affects emissions They produce higher airborne PAH concentrations than lump charcoal, and dramatically higher concentrations than gas grills.6PubMed. Inhalation Exposure to PM-Bound Polycyclic Aromatic Hydrocarbons Released from Barbecue Grills Powered by Gas, Lump Charcoal, and Charcoal Briquettes Their ash carries more trace metals.10Journal of Hazardous Materials. Concentrations and bioaccessibilities of trace elements in barbecue charcoals And many commercial briquettes contain contaminants that fall outside quality standards.9PubMed. Environmental implications of the quality of charcoal briquettes and lump charcoal used for grilling
That said, the gap between briquettes and lump charcoal is much smaller than the gap between either solid fuel and gas. Both charcoal types push PAH-related cancer risk above commonly cited safety thresholds for professional grill operators, while gas stays far below.7PubMed. Inhalation risk to PAHs and BTEX during barbecuing: The role of fuel/food type and route of exposure If you are choosing strictly on health grounds, gas is the clear winner. If you want the flavor profile of charcoal, lump charcoal with no additives is a step up from briquettes. And if you are going to use briquettes regardless, the mitigation steps above, particularly full preheating, drip management, and wind positioning, compress the difference meaningfully.