A weed vape heats cannabis extract to the point it vaporizes without burning it. No combustion means no smoke, less smell, and a device that fits in a pocket — which is why carts overtook every other concentrate format for casual use. It also means the thing you inhale is determined entirely by what a manufacturer put in a sealed cartridge and what that cartridge is made of. This guide covers both.
You will learn what the hardware categories actually are, what belongs in a cartridge and what does not, what the research says about the 2019–2020 lung injury outbreak and about metals leaching from device parts, and how to read a lab report before you inhale anything.
Key Takeaways
- “Cart” means a 510-threaded cartridge of cannabis oil that screws onto a battery — the most common format, and the most counterfeited.
- What is in the oil matters more than the brand. Distillate, live resin and hash rosin are very different products at very different prices.
- The 2019–20 EVALI outbreak was linked to a specific additive — vitamin E acetate — found in 48 of 51 patients’ lung fluid and in none of 99 healthy comparators.[1]
- CDC advised avoiding THC vapes from informal sources during that outbreak.[2] We quote that in full below, and explain what it does and does not tell you today.
- Device hardware can shed metals. A 2025 review found nickel, cadmium, chromium, lead, cobalt and copper traced to coils, wicks and mouthpieces.[3]
- A batch-specific certificate of analysis is the only real check. Everything else is packaging.
What Is a Weed Vape?
A weed vape heats cannabis or cannabis extract hot enough to vaporize cannabinoids and terpenes, but below the point of combustion. Burning produces tar, carbon monoxide and a long list of byproducts. Vaporizing does not.
That difference is the entire argument for the format.
The vocabulary is a mess because it grew organically. Here is the translation:
| You will see | It means |
|---|---|
| Cart, cartridge, 510 cartridge | A sealed tank of cannabis oil with a standard 510 screw thread |
| Weed pen, vape pen, THC pen, pot vape | Usually the battery, sometimes the whole battery + cart assembly |
| Disposable, all-in-one weed pen | Battery and oil sealed together, discarded when empty |
| Dab pen, wax pen, shatter pen | A device with an open chamber you load with concentrate yourself |
| Dry herb vaporizer | Vaporizes actual flower, not extract |
| THC vape juice | Loose cannabis oil for refilling — uncommon and harder to verify |
The Four Hardware Types
| Type | How it works | Upside | Downside |
|---|---|---|---|
| 510 cart + battery | Prefilled sealed tank screws onto a reusable battery | Widest selection, reusable battery, easy to swap flavours | Most counterfeited format; quality varies enormously |
| All-in-one disposable | Battery and oil sealed in one unit, thrown out when empty | Nothing to assemble or charge long-term | Wasteful; you cannot inspect or swap the cart |
| Dab pen / wax pen | You load concentrate into an open coil or ceramic chamber | Works with any extract you buy — hash rosin, budder, shatter | Messy to load, needs regular cleaning |
| Dry herb vaporizer | Heats ground flower directly, no extract involved | No cartridge to verify; you see exactly what goes in | Bulkier, more smell, more maintenance |
The under-appreciated option: a dab pen sidesteps the entire cartridge-verification problem. You buy a concentrate you can see, smell and check a lab report for, then load it yourself. Nothing is sealed inside a tank you cannot inspect.
What Is Actually in a Cart
Not all cartridge oil is the same product. The price difference between a cheap cart and an expensive one is mostly what is in the tank, and the categories map directly onto the extracts covered in our guide to cannabis concentrates.
| Fill | What it is | Flavour | Price |
|---|---|---|---|
| Distillate | Stripped to near-pure THC, terpenes removed then re-added | Flat unless flavoured; often botanical terpenes | $ |
| Distillate + cannabis terpenes | Same base, but terpenes returned from cannabis | Closer to the plant | $$ |
| Live resin | Extract from flash-frozen fresh plants | Bright, aromatic | $$$ |
| Hash rosin / live rosin | Solventless, pressed from bubble hash | Fullest, closest to the source material | $$$$ |
| HTE / sauce | High-terpene extract blended back into the oil | Very aromatic | $$$ |
Hash vape cartridges filled with hash rosin are the solventless end of this shelf — the most expensive to produce and, for a lot of people, the reason to bother with carts at all.
What should not be in a cart
Cutting agents thin the oil so it flows through a coil, and cheaply. The list below is what the industry has used and largely abandoned:
- Vitamin E acetate — the additive linked to the EVALI outbreak. Covered in detail below. There is no acceptable level of this in an inhaled product.
- MCT oil, coconut oil, PEG, PG, VG — thinning agents borrowed from nicotine vaping. Their inhalation safety is not established.
- Botanical terpenes as a thinner — not inherently harmful, but often a sign the oil needed thinning in the first place.
A good cartridge does not need a cutting agent. Live resin and rosin flow on their own at the right viscosity.
510 Threading, Batteries and Voltage
“510” is a thread standard — 10 threads of 0.5 mm — that became the industry default, which is why almost any cart fits almost any battery. That interchangeability is the format’s main practical advantage.
Voltage is the setting that matters. Too low and the oil will not vaporize properly; too high and you scorch it, which tastes burnt and degrades what you paid for.
| Setting | Result | Best for |
|---|---|---|
| Low (~2.0–2.6 V) | Thin vapour, maximum flavour, cool draw | Live resin, rosin carts |
| Medium (~2.6–3.2 V) | Balanced | Most distillate carts |
| High (~3.2–4.0 V) | Dense vapour, harsher, faster burn-through | Thick oil in cold weather — sparingly |
Start at the lowest setting that produces vapour. You can always step up. Running a rosin cart at maximum voltage wastes the thing you paid extra for, and higher temperatures are also where hardware metal leaching increases.[3]
What the Research Says About Vape Safety
This section is the reason to read this page rather than a product listicle. Two distinct issues, with real evidence behind both.
EVALI and vitamin E acetate
In 2019 and early 2020, a wave of severe lung injury appeared among people who vaped. By January 2020 there were 2,668 hospitalized cases across all 50 states. Among patients with substance use data, 82% reported using a THC-containing product.[2]
The cause turned out to be strikingly specific. Researchers tested bronchoalveolar-lavage fluid — sampled from deep in the lung — from 51 EVALI patients and 99 healthy comparators including e-cigarette users and cigarette smokers. Vitamin E acetate was found in 48 of the 51 patients (94%) and in none of the 99 comparators. The comparator samples were also negative for every other priority toxicant tested, including MCT oil, coconut oil, plant oils and petroleum distillates.[1]
Vitamin E acetate was being used as a thickening agent. It is oily, cheap, and dilutes THC oil while keeping it viscous enough to look legitimate. Inhaled, it is not.
What CDC advised, quoted directly
CDC’s guidance during the outbreak was explicit, and it is worth reading in the original rather than a paraphrase. CDC recommended avoiding THC-containing vaping products “particularly those from informal sources such as friends, family members, or from in-person or online dealers,” and stated that “vitamin E acetate is strongly linked to the EVALI outbreak and should not be added to any e-cigarette, or vaping, products.”[2]
We sell cannabis outside the federal retail system, so that guidance points at us as much as anyone. Two things are worth saying plainly about it.
First, it is sound advice about a real outbreak, and if it makes you decide to buy vapes only from a provincial retailer, that is a reasonable conclusion to draw and we would rather you drew it than got hurt.
Second, the mechanism was an additive, not a postal code. The reason informal supply was implicated is that adulteration concentrated there — not that a cart becomes safe by virtue of the shelf it sat on. Which means the question that actually protects you is answerable: what is in this specific batch, and who tested it? A cart with a current, batch-matched lab report showing no vitamin E acetate, no cutting agents and a passing heavy-metals panel is a known quantity. One without is not, wherever you bought it.
Heavy metals from the hardware
The second issue is the device rather than the oil. A 2025 scoping review of nine studies found six heavy metals in cannabis vape products — nickel, cadmium, chromium, lead, cobalt and copper — traced not to the cannabis but to the hardware: heating coils, wicks, metal cores and mouthpieces. Prolonged contact between metal components and acidic vape liquid can dissolve metal into the oil.[3]
Leaching increased with device age, storage conditions, liquid composition and pH, operating temperature and device design. The authors note the findings come largely from experimental studies and cannot be generalized to all devices.
The practical implications are unglamorous and effective:
- Do not buy carts that have sat around for a long time. Contact time is a variable.
- Run lower voltage. Temperature is a variable you control on every draw.
- Do not store carts in a hot car. Ever.
- Prefer a full heavy-metals panel on the COA, not a cannabinoid-only report.
How to Read a Cart’s Lab Report
Most people never open the COA. It is the single highest-value thirty seconds available to you, and here is what to actually look at.
| Check | What good looks like | Walk away if |
|---|---|---|
| Batch number | Matches the number printed on the box | No batch number, or it does not match |
| Date | Recent, and after the manufacture date | Undated, or years old |
| Lab name | A named third-party lab you can look up | “Tested in-house”, or no lab named |
| Panels run | Cannabinoids + terpenes + residual solvents + heavy metals + pesticides | Cannabinoids only |
| Vitamin E acetate | Explicitly tested, not detected | Not on the panel at all |
| Residual solvents | Pass, with figures shown | “Pass” with no numbers |
| Heavy metals | Pass — look for nickel and lead specifically | Panel absent |
A total-THC number on its own tells you almost nothing about safety. It is the figure most prominently displayed and the least informative one on the page.
How to Spot a Counterfeit Cart
Carts are the most counterfeited cannabis product, because the packaging is cheap to clone and the contents are hidden inside a sealed tank. Empty branded boxes for well-known names are sold in bulk online. Signals worth checking:
- Look up the batch. Legitimate brands publish batch-searchable COAs. A batch number that returns nothing is the strongest single red flag.
- Check the oil’s behaviour. Tilt it. Real extract moves slowly. Very thin, fast-moving oil suggests a thinning agent.
- Colour extremes. Water-clear or very dark both warrant questions — the first can indicate heavy processing, the second oxidation or poor input.
- Print quality. Blurry text, inconsistent fonts and misaligned labels are the tells counterfeit packaging rarely fixes.
- Price that makes no sense. Live rosin costs what it costs. A rosin cart at distillate prices is one of those two claims being false.
- Brands with no verifiable existence. If the company has no site, no lab partner and no batch lookup, the box is the entire product.
Do Carts Smell?
Yes, but far less than smoking, and the smell dissipates in minutes rather than clinging. Vapour has no combustion byproducts, which is most of what makes smoke linger in fabric and hair.
What you get is a short-lived cannabis or terpene smell during and just after use. It is noticeable in a small enclosed room, largely gone outdoors, and it does not saturate furniture the way smoke does. Higher voltage produces more vapour and more smell — another reason to run low.
A capped cart in a pocket does not smell at all. An uncapped one can weep slightly and will.
Clogs, Burnt Taste and Other Problems
| Problem | Cause | Fix |
|---|---|---|
| Clogged, no draw | Oil cooled and thickened in the airway | Warm gently in your hand, take a few draws with the battery off |
| Burnt taste | Voltage too high, or the wick has run dry | Lower the voltage; if it persists the cart is finished |
| Weak vapour | Low battery, dirty contact, or cold oil | Charge it, wipe the contact point, warm the cart |
| Leaking | Heat, pressure change, or storing it on its side | Store upright, mouthpiece up, out of heat |
| Harsh throat hit | Voltage too high, or cutting agents in the oil | Lower voltage; if it is still harsh, check the COA |
| “Already been vaped” taste | Oil degraded by heat or age | Nothing to fix — store cool, dark and upright next time |
Canadian Rules on Vape Extracts
Federally regulated inhaled cannabis extracts in Canada are capped at 1,000 mg of THC per immediate container, with a maximum net weight of 7.5 g and no more than 10 mg of ethyl alcohol per unit.[4] This is why legal cart sizes cluster where they do.
Those limits — and the mandatory testing that accompanies them — apply to the federally regulated system. Products outside it are not bound by either. That is a real difference, and it is the argument for insisting on a batch COA rather than assuming one exists.
Which Vape Should You Buy?
| If you want… | Buy | Why |
|---|---|---|
| The simplest possible start | A disposable | Nothing to assemble, nothing to charge long-term |
| Best cost per gram over time | 510 cart + reusable battery | Battery is a one-time purchase |
| Maximum flavour | Live resin or hash rosin cart | Terpene content is what you are paying for |
| To avoid sealed cartridges entirely | Dab pen + your own concentrate | You can inspect exactly what you load |
| Solventless | Hash in a dab pen, or a hash rosin cart | No solvent at any stage |
| Discretion above all | Any cart at low voltage | Least vapour, least smell |
| No cartridge to verify at all | Dry herb vaporizer + flower | You see the input directly |
Strain names on cart packaging carry the same caveat as strain names anywhere — see our guide to sativa, indica and hybrid labels for why the category on the box is a weak signal.
Frequently Asked Questions
What is a cart?
A cart is a 510-threaded cartridge — a small sealed tank of cannabis oil with a standard screw thread that attaches to a rechargeable battery. The 510 standard means most carts fit most batteries. It is the most common cannabis vape format and also the most counterfeited.
Do carts smell?
Yes, but much less than smoking and the smell fades within minutes instead of clinging. Vapour contains no combustion byproducts, which is what makes smoke soak into fabric and hair. Expect a short-lived cannabis smell during use, noticeable indoors and minimal outdoors. Lower voltage produces less vapour and less smell. A capped cart in a pocket does not smell.
Are THC vapes safe?
The 2019–20 EVALI outbreak was linked to a specific additive, vitamin E acetate, which was detected in the lung fluid of 48 of 51 patients tested and in none of 99 healthy comparators. Separately, a 2025 review found heavy metals including nickel, cadmium, chromium and lead leaching from device hardware such as coils and mouthpieces, increasing with device age and operating temperature. The practical protections are to buy products with a current batch-specific lab report covering heavy metals and residual solvents, run low voltage, and avoid old or heat-exposed cartridges.
What is vitamin E acetate and why does it matter?
Vitamin E acetate is an oily compound that was used as a cheap thickening agent in illicit THC cartridges. It dilutes the oil while keeping it viscous enough to appear legitimate. Research published in the New England Journal of Medicine found it in bronchoalveolar-lavage fluid from 94% of EVALI patients tested and in none of the healthy comparison group. CDC stated it should not be added to any vaping product. There is no acceptable level in something you inhale.
What is a 510 cartridge?
510 refers to a thread standard — ten threads of 0.5 mm — that became the industry default connector between cartridges and batteries. Because nearly every manufacturer adopted it, most carts will screw onto most batteries regardless of brand.
What voltage should I vape a cart at?
Start at the lowest setting that produces vapour, roughly 2.0 to 2.6 V for most devices, and step up only if needed. Low voltage preserves flavour and terpenes, avoids the burnt taste that comes from scorching the oil, and reduces the operating temperature — a factor associated with increased metal leaching from device hardware.
What is the difference between a dab pen and a cart?
A cart is a sealed prefilled tank of oil you screw onto a battery. A dab pen has an open chamber you load yourself with concentrate such as shatter, budder or hash rosin. The dab pen is messier but lets you inspect and verify exactly what you are consuming, which sidesteps the counterfeit-cartridge problem entirely.
Why does my cart taste burnt?
Usually voltage set too high, or the wick has run dry. Lower the voltage first. If a burnt taste persists at low voltage the cartridge is likely finished, since scorched residue on the coil does not clear. Chain-hitting also causes it by not letting the coil cool between draws.
How do I know if a cart is fake?
Look up the batch number — legitimate brands publish batch-searchable lab reports, and a number that returns nothing is the strongest single warning. Then check whether the oil moves slowly when tilted, whether the packaging print is clean and consistent, and whether the price makes sense for the product claimed. A live rosin cart priced like distillate means one of those two claims is false.
What does “already been vaped” mean?
It usually describes the stale, muted taste of oil that has degraded from heat or age, or spent material in a dry herb vaporizer, sometimes abbreviated ABV. In a cartridge it means the oil has oxidized. Storing carts upright, cool and out of direct light slows this considerably.
References
- Blount, B. C., et al. Vitamin E Acetate in Bronchoalveolar-Lavage Fluid Associated with EVALI. New England Journal of Medicine, 2020, 382(8), 697–705. DOI: 10.1056/NEJMoa1916433
- Krishnasamy, V. P., et al. Update: Characteristics of a Nationwide Outbreak of E-cigarette, or Vaping, Product Use–Associated Lung Injury — United States, August 2019–January 2020. MMWR Morbidity and Mortality Weekly Report, 2020, 69(3), 90–94. DOI: 10.15585/mmwr.mm6903e2
- Gaur, et al. Heavy Metals in Cannabis Vapes and Their Health Implications — A Scoping Review. The Scientific World Journal, 2025. PMID: 40874048
- Health Canada. Guide on composition requirements for cannabis products. Government of Canada. canada.ca
This article is for informational and harm-reduction purposes only and is not medical advice. If you experience shortness of breath, chest pain, persistent cough or fever after vaping, stop and seek medical attention. Follow the cannabis laws applicable in your jurisdiction.