A “cart,” short for cartridge, is a small, pre-filled container of cannabis oil or concentrate used with a vape pen. These devices heat the oil, converting it into an inhalable aerosol that delivers a high concentration of tetrahydrocannabinol (THC). The health risks depend heavily on the cartridge’s contents, the device’s hardware quality, and the user’s frequency of use. These factors reveal distinct health concerns, ranging from acute lung injury to long-term neurological impacts.
The Immediate Risk of Illicit Additives and Cutting Agents
The most significant acute danger comes from unregulated or black market carts, where manufacturers use cutting agents (diluents) to increase volume and viscosity for higher profit margins. The most notorious additive is Vitamin E Acetate, a chemical strongly linked to the outbreak of E-cigarette or Vaping Product Use-Associated Lung Injury (EVALI).
When vaporized and inhaled, this fat-soluble oil coats the alveoli, the tiny air sacs in the lungs where gas exchange occurs. This oil interferes with pulmonary surfactant, which prevents the alveoli from collapsing upon exhalation. This disruption can lead to severe pneumonitis and acute respiratory distress.
Other diluents, such as propylene glycol (PG) and polyethylene glycol (PEG), pose risks when heated to vaporization temperatures. Heating these substances can generate toxic byproducts, including carbonyl compounds like formaldehyde and acrolein. These compounds are known irritants that cause inflammation and damage to the respiratory system, dramatically increasing the potential for immediate lung injury.
Potential Harm from Heating Elements and Hardware
Beyond the chemical composition of the oil, the physical components of the cartridge can introduce toxic substances. The heating coil and other metal parts, often made of stainless steel, can leach heavy metals into the cannabis oil. Metals like lead, nickel, chromium, and copper have been detected in the aerosol produced by vape pens.
This leaching process is accelerated by high operating temperatures and the acidic nature of some cannabis concentrates. Contamination can occur even before the first use, as metal nanoparticles migrate into the liquid during manufacturing and storage. When inhaled, these metal particles are delivered directly into the lungs, where they can accumulate and potentially lead to systemic health issues.
The Impact of Concentrated Delivery on the Respiratory System
Even without illicit additives or metal contamination, inhaling highly concentrated cannabis aerosol presents a unique challenge to the respiratory system. Carts contain THC concentrations ranging from 50% up to 95%, which is dramatically higher than the 15% to 25% found in traditional cannabis flower. This high potency means a single inhalation delivers a much greater dose of cannabinoids and other vaporized compounds.
The vaporized oil forms an aerosol of tiny droplets that penetrate deep into the pulmonary tissue. This continuous exposure to concentrated irritants can cause chronic inflammation and changes in the airways. Studies suggest that cannabis vapor may induce gene expression changes in lung cells similar to those caused by cannabis smoke, indicating cellular stress. Furthermore, inhaling oil-based substances carries a theoretical risk of lipoid pneumonia, a condition characterized by fat deposits in the lungs that trigger an inflammatory response.
Dependence and Cognitive Concerns
The high potency and discreet nature of cannabis carts contribute to significant non-respiratory health risks, particularly concerning dependence and cognitive function. The rapid onset of effects from vaping highly concentrated THC increases the likelihood of developing a Cannabis Use Disorder (CUD). This rapid delivery and high concentration make it easier for users to consume more frequent and larger doses, which are primary factors in addiction risk.
The effect of high-potency THC on the developing brain of adolescents is a particular concern, as the brain continues to mature until around age 25. Regular use of highly concentrated cannabis during this period has been linked to potential long-term deficits in cognitive functions like attention, memory, and learning. The ease of use and ability to conceal a vape pen facilitates frequent, high-dose consumption, increasing the risk of negative neurological outcomes.