By Ken Fry, Founder & CEO, Terps USA

SHORT ANSWER

The EVALI investigation produced a strong finding, but not the absolute one often repeated afterward. CDC found vitamin E acetate strongly linked to the outbreak, particularly in THC-containing products from informal sources. At the same time, CDC repeatedly said the evidence was not sufficient to rule out contributions from other chemicals in some cases.

What the lung-fluid evidence showed

In a study of bronchoalveolar-lavage fluid from 51 EVALI patients across 16 states, vitamin E acetate was identified in 48 of 51 case patients and not in the healthy comparison group. That made vitamin E acetate the strongest chemical signal identified in the investigation.

What CDC did not say

CDC did not conclude that one ingredient explained every case. Its published guidance continued to state that other chemicals of concern could not be ruled out and that more than one cause might have contributed. That distinction matters when the outbreak is used to defend or condemn unrelated ingredients.

Why “explicitly cleared” is too strong

The absence of an ingredient from the leading causal hypothesis is not the same as proving that ingredient played no role in any case. PG, VG and PEG should be evaluated on their own toxicology and exposure evidence rather than declared guilty by association with EVALI — or declared universally safe because vitamin E acetate became the leading explanation.

The lesson EVALI actually supports

Ingredient identity matters. Product source matters. Formulation matters. And when a public-health investigation says one substance is strongly linked while other contributors cannot be ruled out, both parts of that conclusion belong in the conversation.

FAQ

What did CDC conclude about vitamin E acetate and EVALI?

CDC concluded that vitamin E acetate was strongly linked to the EVALI outbreak. It was detected in lung-fluid samples from geographically diverse patients and was not detected in healthy comparison participants in a major bronchoalveolar-lavage study.

Did CDC prove that vitamin E acetate caused every EVALI case?

No. CDC repeatedly stated that the evidence was not sufficient to rule out contributions from other chemicals of concern and that more than one cause could have been involved.

Did CDC explicitly clear PG, VG or PEG as causes of EVALI?

No. The investigation strongly implicated vitamin E acetate, but CDC did not issue a blanket finding that PG, VG or PEG had been proven incapable of contributing to any EVALI case. Claims that those ingredients were “explicitly cleared” go beyond CDC’s published conclusion.

Sources

1. Fry, K. (2026). “The Science of Safety: Debunking the Myths Surrounding Propylene Glycol and Polyethylene Glycol in Vaping Applications.” Terps USA Research. DOI: 10.5281/zenodo.21005414

2. Blount, B. C., et al. (2020). Vitamin E Acetate in Bronchoalveolar-Lavage Fluid Associated with EVALI. New England Journal of Medicine, 382, 697–705.

3. Centers for Disease Control and Prevention. (2020). Update: Characteristics of a Nationwide Outbreak of E-cigarette, or Vaping, Product Use–Associated Lung Injury — United States, August 2019–January 2020. MMWR, 69.

This article is for informational and industry education purposes only. Terps USA products do not contain THC or CBD. These statements have not been evaluated by the FDA. Readers are encouraged to consult the cited primary sources directly.