Landmark study identified vitamin E acetate as the primary toxicant behind the 2019 vaping lung injury outbreak | Research

The takeaway

Vitamin E acetate was found in the lung fluid of 94% of EVALI patients but in none of the healthy comparators, establishing it as the strongest chemical link to the 2019 vaping illness outbreak.

Cannabis consumers, vapers, public health professionals, harm reduction advocates

94% of EVALI patients had vitamin E acetate in their lung fluid; 0% of healthy comparators did

The Backstory

In the summer of 2019, previously healthy teenagers and young adults began showing up in emergency departments across the United States with a terrifying constellation of symptoms: shortness of breath, chest pain, nausea, vomiting, and fever. Chest X-rays showed widespread lung infiltrates — the kind of damage usually seen in severe pneumonia or chemical exposure. But cultures were negative. These patients did not have infections.

Within weeks, they were on ventilators. Within months, they were dying.

By the time the CDC stopped counting in February 2020, the epidemic had hospitalized 2,807 people in all 50 states and killed 68 — many of them in their twenties and thirties. The cause was something no physician had been trained to look for: a lipid thickening agent called vitamin E acetate, used to dilute black-market THC vape cartridges.

The Investigation

Benjamin Blount and a massive team of CDC, FDA, and state health department scientists conducted the study that cracked the case. It was published in the New England Journal of Medicine — the most prestigious medical journal in the world — and it provided the direct evidence linking vitamin E acetate to the lung injury.

Study Design

Finding the Smoking Gun in Lung Fluid

EVALI patients

from 16 states — BAL fluid collected and analyzed

Healthy controls

nonsmokers, vapers, and cigarette smokers from ongoing study

Mass spectrometry

Detection method

isotope dilution — testing for 6 priority toxicant categories

NEJM

Published in

February 20, 2020

Blount et al. (2020), N Engl J Med 382(8):697-705

The methodological choice was critical. Instead of testing the vape products themselves — which would only show what was in the cartridge, not what reached the lungs — the investigators tested bronchoalveolar lavage (BAL) fluid: the liquid washed directly from patients' damaged lungs. This provided direct evidence of what was actually present at the site of injury.

They tested for six priority toxicant categories: vitamin E acetate, plant oils, medium-chain triglyceride (MCT) oil, coconut oil, petroleum distillates, and diluent terpenes.

The Results

94%

of EVALI patients (48 of 51) had vitamin E acetate detected in their bronchoalveolar lavage fluid. Zero of 99 healthy controls had any detectable vitamin E acetate.

No other priority toxicant was found in the case patients — except coconut oil and limonene in one patient each. This was not a cocktail of contaminants. It was one substance, overwhelmingly present in cases and completely absent in controls.

Blount et al. (2020), N Engl J Med

The specificity was remarkable. Vitamin E acetate was present in nearly every EVALI patient and absent in every healthy comparator — including the comparators who vaped nicotine products or smoked cigarettes. The signal was as clear as epidemiological evidence gets.

Key Data Points

The Evidence Linking Vitamin E Acetate to EVALI

Vitamin E acetate in patients

48 of 51 (94%) — detected directly in damaged lung tissue fluid

Vitamin E acetate in controls

0 of 99 (0%) — completely absent in healthy vapers, smokers, and non-smokers

THC product involvement

47 of 50 (94%) patients with available data had detectable THC/metabolites or reported vaping THC products

Nicotine involvement

30 of 47 (64%) also had nicotine or metabolites — many patients used both THC and nicotine products

Other toxicants

None detected in case patients except coconut oil and limonene in 1 patient each

Blount et al. (2020), N Engl J Med

What Is Vitamin E Acetate and Why Was It There?

Biological Mechanism

How a Cosmetic Ingredient Became a Lung Toxin

▼

Proposed mechanism

The cruelty of the mechanism is that vitamin E acetate is genuinely safe in every other context. You can eat it. You can rub it on your skin. It is in thousands of consumer products. But the lungs are not the skin. The alveolar membrane is one cell thick. What is harmless elsewhere is catastrophic when aerosolized and inhaled into the deepest reaches of the respiratory system.

The Timeline of a Public Health Crisis

Research Timeline

The EVALI Outbreak

April 2019

August 2019

September 2019

November 2019

February 2020

March 2020

Historical research record

The Tragedy of Prohibition

EVALI was not a failure of cannabis. It was a failure of cannabis policy.

Vitamin E acetate was never used in legal, regulated THC vape products. State-licensed cannabis manufacturers are required to test their products and have no economic incentive to dilute them — their products are tested, labeled, and traceable. The adulteration occurred exclusively in the black market, where unregulated producers cut THC oil with a cheap thickener to maximize profit with no quality oversight.

Myth vs. Reality

✕Myth

Vaping cannabis is inherently dangerous because of EVALI

✓Reality

EVALI was caused by vitamin E acetate, a specific adulterant found almost exclusively in black-market THC vape cartridges. Legal, tested cannabis vape products were not implicated. The lesson is not that cannabis vaping is dangerous — it is that unregulated cannabis markets are dangerous. Every death from EVALI was a death caused by prohibition's unintended consequences.

The Evidence

Blount et al. (2020): 94% of EVALI patients used THC products, and vitamin E acetate was the identified toxicant

This framing is not pro-cannabis advocacy. It is the direct conclusion of the public health evidence. The CDC's own investigation found that the outbreak was driven by illicit products in an unregulated market. States with legal cannabis markets saw lower rates of EVALI. The epidemic disproportionately affected communities where legal access was unavailable and black-market products filled the gap.

What People Get Wrong

The collateral damage from EVALI extended far beyond the direct victims. The initial public health messaging — "stop vaping" without distinction between THC and nicotine products — caused panic among nicotine vapers who were using a regulated harm reduction tool to quit cigarettes. Some returned to smoking, arguably increasing their long-term health risk. The confusion persists: surveys show that many Americans still believe that all vaping is equally dangerous, conflating black-market THC cartridges with FDA-regulated nicotine products.

For cannabis users, the lasting lesson is simpler: know what is in your vape. If you cannot verify the source, the testing, and the contents, you are gambling with your lungs. Our vape safety guide covers how to identify regulated products and what to avoid.

Is vaping cannabis safe now?

Legal, lab-tested cannabis vape products from regulated dispensaries were not implicated in EVALI. The risk came from black-market cartridges containing vitamin E acetate. If you use cannabis vapes, buy only from licensed sources where products are tested and labeled. Avoid any cartridge purchased from an unlicensed source, regardless of packaging.

What were the symptoms of EVALI?

Shortness of breath, chest pain, cough, nausea, vomiting, diarrhea, abdominal pain, fever, chills, and weight loss. Symptoms typically developed over days to weeks. Severe cases progressed to respiratory failure requiring mechanical ventilation. The presentation mimicked severe pneumonia but did not respond to antibiotics.

Could EVALI happen again?

Yes. Black-market THC vape cartridges continue to circulate, and there is no guarantee that vitamin E acetate or other adulterants have been completely eliminated. As long as unregulated cannabis markets exist, the risk of contaminated products remains. Legalization with proper testing requirements is the most effective prevention strategy.

Were nicotine vapes also dangerous?

The EVALI outbreak was overwhelmingly associated with THC-containing products (94% of cases). Some patients also used nicotine products, but vitamin E acetate was not found in commercially available nicotine vapes. The initial conflation of THC and nicotine vaping in public messaging was a significant public health communication failure.

Vitamin E Acetate in Bronchoalveolar-Lavage Fluid Associated with EVALI

Blount BC, Karwowski MP, Shields PG, et al. (2020) · New England Journal of Medicine

PubMed DOI

Related Research

Key studies in this area

Vitamin E Acetate in BAL Fluid Associated with EVALI

Blount et al. (2020)

What the researchers found

Vitamin E acetate was detected in bronchoalveolar lavage fluid from 48 of 51 EVALI patients (94%) across 16 states but was absent in all 99 healthy comparators. Among case patients with available data, 94% had detectable THC or its metabolites in lung fluid or reported vaping THC products in the 90 days before symptom onset.

Why it matters

This NEJM study provided the strongest direct evidence linking vitamin E acetate to the EVALI outbreak, helping public health authorities identify the cause and issue targeted warnings about illicit THC vaping products.

The numbers in context

48 of 51 (94%) EVALI patients had vitamin E acetate in lung fluid. 47 of 50 (94%) had THC or metabolites in lung fluid or reported vaping THC. 30 of 47 (64%) also had nicotine or metabolites. Zero healthy comparators had vitamin E acetate.

How the study worked

BAL fluids from 51 EVALI patients in 16 states and 99 healthy participants were analyzed using isotope dilution mass spectrometry for vitamin E acetate, plant oils, medium-chain triglyceride oil, coconut oil, petroleum distillates, and diluent terpenes.

What this study cannot tell us

Convenience sample; no BAL fluid was available from all patients; cannot completely rule out other contributing toxicants; the study identifies association, not definitive causation.

How to read the evidence

Large multi-state case-control study published in the New England Journal of Medicine with strong analytical chemistry methods.

When this study was published

Published in 2020.

The bigger picture

The EVALI outbreak, which sickened thousands and killed dozens in 2019, was ultimately traced to vitamin E acetate used as a cutting agent primarily in illicit THC vape cartridges, not in regulated cannabis or nicotine vaping products.

Questions still open

What concentration of vitamin E acetate triggers lung injury? Could other cutting agents in illicit vape products also cause harm at lower rates?

Common questions

Was vitamin E acetate found in legal vaping products?

The study focused on patient lung fluid rather than product testing, but the EVALI outbreak was overwhelmingly linked to illicit THC vape cartridges. Vitamin E acetate was used as a cutting agent to dilute THC oil in black-market products.

Does this mean nicotine vaping is safe?

This study specifically investigated the EVALI outbreak, which was primarily associated with illicit THC vaping products containing vitamin E acetate. It does not address the long-term safety of nicotine vaping products.

Read the original research

Vitamin E Acetate in Bronchoalveolar-Lavage Fluid Associated with EVALI.

The New England journal of medicine, 382(8), 697-705

View on PubMed ↗Publisher’s paper ↗

Citation

Blount, Benjamin C; Karwowski, Mateusz P; Shields, Peter G; Morel-Espinosa, Maria; Valentin-Blasini, Liza; Gardner, Michael; Braselton, Martha; Brosius, Christina R; Caron, Kevin T; Chambers, David; Corstvet, Joseph; Cowan, Elizabeth; De Jesús, Víctor R; Espinosa, Paul; Fernandez, Carolina; Holder, Cory; Kuklenyik, Zsuzsanna; Kusovschi, Jennifer D; Newman, Cody; Reis, Gregory B; Rees, Jon; Reese, Chris; Silva, Lalith; Seyler, Tiffany; Song, Min-Ae; Sosnoff, Connie; Spitzer, Carleen R; Tevis, Denise; Wang, Lanqing; Watson, Cliff; Wewers, Mark D; Xia, Baoyun; Heitkemper, Douglas T; Ghinai, Isaac; Layden, Jennifer; Briss, Peter; King, Brian A; Delaney, Lisa J; Jones, Christopher M; Baldwin, Grant T; Patel, Anita; Meaney-Delman, Dana; Rose, Dale; Krishnasamy, Vikram; Barr, John R; Thomas, Jerry; Pirkle, James L. (2020). Vitamin E Acetate in Bronchoalveolar-Lavage Fluid Associated with EVALI.. The New England journal of medicine, 382(8), 697-705. https://doi.org/10.1056/NEJMoa1916433