PHOTO COURTESY OF Skule™

They’re a familiar September sight on St. George campus: newly-minted engineering students with their skin stained a bright purple.

Large vats of violet dye and crowds of eager first-year students ready to submerge themselves are common to frosh orientation events at engineering faculties across Canada. The origin and meaning of the tradition are shrouded in mystery, but the infusion of the chemical gentian violet to a dyeing solution has become iconic.

The custom has now come under scrutiny due to a Health Canada warning, which associates the ingestion of gentian violet with an increased risk of cancer.

Warning stemmed from investigation by United Nations

The warning was issued on June 12, but gentian violet’s toxicity has been studied for some time. The seeds of what would become Health Canada’s advisory were sown in 2013 in a report written by the Joint Expert Committee on Food Additives (JECFA).

The JECFA is composed of medical experts from the Food and Agriculture Organization (FAO) and the World Health Organization (WHO). Both are organs of the United Nations.

Although the report was the first JECFA evaluation of gentian violet, the publication was more akin to a literature review than an experimental study. The investigators searched the databases Medline, CABI, Agricola, and Toxnet for studies on the toxicity of gentian violet.

Health Canada also provided its own collation and review of data on the chemical. The team reviewed papers dated as far back as 1980.

Gentian violet is typically used as a component of veterinary disinfectants, and the majority of the JECFA report concerns how much gentian violet residue could be found in the remains of food-producing animals. However, an important finding was that gentian violet can bind to and alter DNA.

The researchers also noted chemical similarities of the dye to malachite green, another chemical already acknowledged as carcinogenic. Accordingly, the expert committee resolved that there could not be an acceptable daily intake of gentian violet for humans.

International representatives debate over wording of advisory

Following the report’s publication, the JEFCA’s results were forwarded to the Codex Committee on Veterinary Drugs in Food (CCRVDF). The CCRVDF is a subsidiary of the Codex Alimentarius Commission, another joint FAO-WHO organization that oversees food-related advisories worldwide. The next convening of the CCRVDF came in 2015, two years after the JECFA’s determination.

Various national delegations to the CCRVDF agreed that a Risk Management Recommendation (RMR) needed to be applied to gentian violet, but they disputed over its precise wording.

Throughout three sessions, spanning from 2015–2018, the Commission debated the inclusion of a sentence specifically condemning the use of the chemical on food-producing animals.

Ultimately, in an April 2018 report, the committee decided to exclude the precise condemnation to “allow member countries to choose appropriate risk management approaches to prevent residues of Gentian Violet in food.”

This RMR was then sent for approval to the entire Codex Alimentarius Commission, which it received in July 2018.

Where does Health Canada come in?

Upon receiving notice of the RMR, Health Canada initiated its own review process to confirm the findings. This involved the analysis of Canadian reports of illness associated with gentian violet before comparing local findings to international reports.

After nearly a year of study, researchers decided that although there were no cases of gentian violet being linked to cancer in humans, the reports of carcinogenicity in animals were enough to warrant a warning.

The department then worked with manufacturers to remove from circulation the single human non-prescription medication and nine veterinary medications available in Canada that list gentian violet as an ingredient.

Three licensed medical devices continue to use gentian violet as part of a sterile dressing. However, Health Canada has assessed that they do not pose a risk to human health due to the short exposure time of gentian violet to patients.

Risk of applying gentian violet to skin is unclear

It is important to note that the entire process of investigation into gentian violet has been focused on toxicity if ingested, which is typically not a component of engineering orientation activities. Health Canada acknowledged this focus in its safety review on the substance, explicitly stating that the result of applying gentian violet to the skin is “unknown.” 

“Generally, the amount of a chemical that can get absorbed through the skin is small, but this is chemical-dependent, and I’m not sure anyone has ever looked to see whether gentian violet gets into the systemic circulation after topical application,” wrote Dr. Denis Grant, a professor in the Department of Pharmacology & Toxicology, to The Varsity.

“Some chemicals can cause skin cancer if they’re topically applied. All in all, given the theoretical plausibility and limited demonstrated evidence for a cancer link, in my opinion it would be prudent to avoid bathing in the stuff.”

Where will the engineering tradition go from here?

While the risks of using gentian violet are now evident, the dyeing tradition is seen as an integral component of engineering student culture that should be maintained.

“The Toike really loves the purple dye tradition!” wrote Joanna Melnyk, Editor-in-Chief of the Toike Oike, to The Varsity. The Toike Oike is a humour publication managed by U of T’s Engineering Society for the purpose of commenting on aspects of engineering culture. 

Melnyk continued, “We feel really cool with our sword(s), wooden sticks, and red wagon, looking like a gang of people with a strange skin condition wielding potentially dangerous items!”

While the tradition is planned to continue this September, the Engineering Society is dedicated to providing a safe F!rosh to all first-year engineering students.

“Although the health concerns with gentian violet pertain to quantities and uses different from our own, we will not be using this dye for Orientation Week,” wrote Ben Mucsi, Chair of the Engineering Society’s Orientation Committee, to The Varsity. “At this point, we have studied a broad range of alternatives and we want to make sure that we are thorough and careful in our decision-making.”

“We are being very diligent in evaluation of our options to ensure that we provide the safest and most enjoyable experience during Orientation Week,” he continued. “Our goal is to ensure that all incoming students have the option to safely participate in our long-standing tradition, and my team, in collaboration with the Engineering Society leadership, have been working hard throughout the summer to try to make that happen!”

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