A cartridge is a self-contained unit that holds a substance and delivers it through a device. The term applies across many industries: ink cartridges slot into printers, anesthetic cartridges are used in dental syringes, and ammunition cartridges hold a bullet with its propellant charge. But the most commonly searched type today is the vape cartridge, a small pre-filled container that attaches to a battery-powered device and turns liquid into inhalable vapor. This article focuses primarily on vape cartridges, with a look at other common types.
How Vape Cartridges Work
A vape cartridge is a small, usually transparent tank filled with liquid concentrate. It screws or snaps onto a battery (most commonly using a universal connector called a 510 thread) that powers a tiny heating element inside. When you inhale or press a button, the battery sends electricity to a thin metal filament, which heats the liquid until it turns into an aerosol you breathe in through a metal air tube at the top.
The heating element sits inside a structure of ceramic or fibrous wicking material that absorbs liquid from the tank and feeds it to the filament. This wicking action is critical. When a coil is properly saturated with liquid, it typically operates between 100 and 400°C. A dry coil, one that has run out of liquid or isn’t wicking efficiently, can spike to temperatures as high as 1,000°C. At those extremes, internal materials can char and decompose, producing harmful byproducts.
Different liquids require different heat levels. Thin distillates vaporize well at lower voltages (around 2.2 to 2.8 volts), while thicker oils need more power, typically 3.2 to 3.8 volts. Starting at a low setting and increasing gradually helps prevent burning the coil or degrading the flavor compounds in the liquid.
What’s Inside the Liquid
Nicotine vape cartridges use propylene glycol (PG) and vegetable glycerin (VG) as their base solvents. These two liquids serve as thinning agents that make the nicotine easier to vaporize and carry flavoring compounds. Cannabis cartridges work differently. THC and CBD oils are naturally thick, so manufacturers add various cutting agents to adjust the consistency. Some use medium-chain triglycerides (MCTs), which are coconut-derived oils. Others have used phytol, a compound found naturally in plants.
The cutting agent that drew the most attention was vitamin E acetate. It was added to illicit and counterfeit THC cartridges as a thickening agent because it mimics the look and feel of high-quality cannabis oil while being far cheaper. In 2019, vitamin E acetate was linked to a wave of severe lung injuries known as EVALI (e-cigarette or vaping product use-associated lung injury), which hospitalized thousands of people across the United States. The compound was found in the lung fluid of affected patients, and its use highlighted the risks of unregulated cartridge products.
Materials and Metal Exposure
The internal components of a cartridge are surprisingly complex. Disassembly studies have found filament wires embedded in cylindrical ceramics, wrapped in fibrous insulation, and housed inside rubbery envelopes within metal inserts. Tank walls are made from plastic or glass, and wicks can be made of cotton, silica glass fibers, or nylon. One study identified PTFE (the same polymer used in nonstick cookware) inside a cartridge, a material that can decompose and cause serious illness when heated above roughly 300°C.
Heating these metal components also releases trace metals into the aerosol. Research on cannabis vape aerosols has detected copper, chromium, nickel, manganese, lead, and tin in particle sizes as small as 20 to 300 nanometers. These nano-sized particles can penetrate deep into lung tissue. Concentrations varied by product type, but some cartridges produced nickel levels of 0.25 mg/m³ and chromium levels of 0.12 mg/m³ in the aerosol. Lower-quality or counterfeit cartridges, and those run at excessively high temperatures, tend to release higher concentrations.
Regulation in the U.S.
The FDA regulates the manufacture, import, packaging, labeling, advertising, promotion, sale, and distribution of electronic nicotine delivery systems, and cartridges are explicitly included as regulated components. Any company that makes, modifies, assembles, or imports vape cartridges must comply with manufacturer requirements. In practice, this means nicotine cartridge makers are supposed to submit their products for FDA review before selling them legally.
Cannabis cartridges fall outside FDA jurisdiction because cannabis remains federally illegal. They are instead regulated at the state level, which means quality standards, testing requirements, and labeling rules vary dramatically depending on where you buy them. Products sold outside licensed dispensaries have no regulatory oversight at all, which is how vitamin E acetate and other harmful additives entered the market.
Environmental Waste
Disposable vape cartridges and all-in-one vape devices create a growing waste problem. A material analysis found the median dry weight of a disposable vape is about 50 grams, with the main materials being either plastic (up to 80% of the device by weight) or metal (up to 85%, including the battery). The lithium-ion batteries inside contain copper, cobalt, iron, and nickel, along with trace amounts of gold, barium, mercury, and lead.
Most disposable vapes are not recycled. They end up in general waste, where battery chemicals can leach into soil and water. Polycarbonate plastic makes up most of the casing, and it does not biodegrade in any meaningful timeframe. The sheer volume of single-use devices discarded each year has prompted several countries and municipalities to explore bans or deposit-return schemes for disposable vapes.
Other Types of Cartridges
Dental Anesthetic Cartridges
In dentistry, a cartridge is a small glass cylinder, typically 1.8 or 2.2 milliliters, pre-filled with a local anesthetic solution. It loads into a syringe that the dentist uses for injections before procedures. The most common anesthetic is lidocaine at a 2% concentration, which works out to about 36 to 44 milligrams per cartridge depending on volume. Some cartridges also contain a vasoconstrictor (a chemical that narrows blood vessels at the injection site) to make the numbing effect last longer and reduce bleeding.
Insulin Pen Cartridges
Insulin cartridges are pre-filled cylinders that slot into reusable pen devices, replacing the traditional vial-and-syringe method. Clinical data shows that pen-based cartridge systems improve patient adherence to insulin schedules and reduce episodes of dangerously low blood sugar compared to vials. Patients consistently report preferring pens for their convenience and ease of use, which matters for a medication that many people need to take multiple times per day for the rest of their lives.
Printer and Ammunition Cartridges
Ink and toner cartridges hold the pigment that printers deposit onto paper. Inkjet cartridges contain liquid ink, while laser printer cartridges hold a fine powder called toner. Both are designed to snap into place and be replaced when empty, though refill and recycling programs exist for most major brands. Ammunition cartridges, also called rounds, are self-contained units that hold a projectile, a propellant charge, and a primer that ignites the charge when struck by a firing pin. The term “cartridge” in all these cases carries the same basic idea: a sealed, replaceable container purpose-built for a specific device.