Key Points:
- Researchers discovered that the contents of many tattoo inks are not listed in full in their ingredient labels.
- Some of the ingredients in tattoo ink can degrade over time into known carcinogens.
- Even though the tattoo industry is monitored at the local level, there is currently no federal oversight to ensure the safety of tattoo inks.
Ötzi the Iceman, a 4,000-year-old mummy discovered in Europe, is the oldest known example of a tattooed human body. Since then, tattoos have been used the world over for both ceremonial and decorative purposes. Despite their popularity, however, very little is known about the composition of inks used in tattoos nowadays.
Regulatory bodies in the United States do not govern the production of tattoo inks. This motivated a group of researchers from Binghamton University to study the ingredients of inks used by artists. They discovered discrepancies between the ingredients and their labels, and the presence of potentially hazardous components. A presentation of the team’s study was given at the fall meeting of the American Chemical Society (ACS).
Throughout the course of their investigation, the researchers learned that tattoo artists actually knew little about the composition of tattoo inks. Furthermore, they discovered no oversight at the federal level regarding the manufacturing of such inks. This might be a cause for concern, because the dyes used in tattoo inks are also used in the production of industrial goods not meant for human applications.
The researchers analyzed the chemicals used in the dyes and in the solutions that transfer the dyes to the dermal layer of human skin. Using Raman spectroscopy, nuclear magnetic resonance spectroscopy and electron microscopy, the team discovered chemicals that were not represented on some of the inks’ ingredient labels. In one instance, they found a sample containing ethanol, a commonly used ink solvent. The solvent, however, was not included as one of the ingredients.
“Every time we looked at one of the inks, we found something that gave me pause,” said John Swierk, one of the lead researchers. “For example, 23 of 56 different inks analyzed to date suggest an azo-containing dye is present.”
Although many azo pigments do not cause health concerns when they are chemically intact, bacteria or ultraviolet light can degrade them into another nitrogen-based compound that is a potential carcinogen.
Additionally, about half of the inks analyzed contain particles smaller than 100 nm.
“That’s a concerning size range,” said Swierk. “Particles of this size can get through the cell membrane and potentially cause harm.”