5.1. Safety Data Required for the Assessment of Substances

Data on Physico-Chemical Properties:

• basic physico-chemical properties according to Regulation (EC) 1907/2006
• the manufacturer must ensure the purity of all ingredients (heavy metals, amines, PAH, etc.) in the final product;
• if substances are manufactured or with pre-mixed chemicals, all ingredients and additives of these have to be listed as well.

Toxicological Data:

For each ingredient, all available toxicological data have to be provided (e.g. by public safety dossiers, REACH registration dossiers published on the website of the European Chemical Agency (ECHA), scientific literature or other). The minimal toxicological requirements for tattoo ink ingredients must therefore be seen in addition to the requirements set out in paragraph 3.1 and 3.2. If any toxicological property is known for which threshold concentrations (Minimal Effect Levels, or similar) exist, it shall not be used in a concentration able to harm the health during their application as tattoo / PMU ink. A guidance document for assessment of safe us in tattoo ink with the appropriate safety factors and read-across from other routes of exposure shall be provided by the authorities.

Since the majority of substances in tattoo inks are known from other fields of industrial, medical or cosmetical applications, a vast amount of data is already available. Since tattooing and permanent make-up is a voluntary exposure, this does not justify additional animal testing. The minimal requirement for all of these substances are:

• irritation and corrosion in vitro (skin, mucous membranes);
• sensitization in vitro, including pre-treatment with UVA (AOP);
• phototoxicity (for substances absorbing light between 400-800 nm, e.g. pigments);
• investigation of light stability
• bacterial and mammalian genotoxicity in vitro 

Toxicological data for safety assessment should be obtained from test methods using guidelines whenever they exist (for example, Organisation for Economic Co-operation and Development OECD, European Union).

5.2. List of Restricted Substances

Table 1 [taken from ECHA restriction proposal, March 2019, if not declared otherwise]:

Substance name (EC#; CAS#): Proposed concentration limit

Mercury (231-106-7; 7439-97-6): 0.2 mg/kg

Nickel (231-111-4;7440-02-0): 10 mg/kg

Tin (231-141-8;7440-31-5): 50 mg/kg

Antimony (231-146-5; 7440-36-0): 200 mg/kg

Arsenic (231-148-6; 7440-38-2): techn. achievable: 0.6 ppm (0.008 mg/kg in the original REACH proposal)

Barium, soluble (231-49-1; 7440-39-3): 8 400 mg/kg

Cadmium (231-152-8; 7440-43-9): 0.2 mg/kg

Chromium(VI) (231-157-5; 7440-47-3): 0.2 mg/kg

Cobalt (231-158-0; 7440-48-4): 25 mg/kg

Copper, soluble (231-159-6; 7440-50-8): 250 mg/kg

Zinc, soluble (231-175-3; 7440-66-6 2): 300 mg/kg

Lead (231-100-4; 7439-92-1): techn. achievable: 2 ppm (0.7 mg/kg in the original REACH proposal)

Selenium (231-957-4; 7782-49-2): 2 mg/kg

Methanol (200-659-6; 67-56-1): 10.9% w/w

Free primary aromatic amines (with toxic properties defined under paragraph 4.2): 5 mg/kg (each substance)

Polycyclic-aromatic hydrocarbons (PAH)(With toxic properties defined under paragraph 4.2): 0.5 mg/kg (each substance)

2-methyl-p-phenylenediamine (202-442-1; 95-70-5): 5 mg/kg

p-Phenylenediamine (PPD, 203-404-7; 106-50-3): 5 mg/kg

Sulphanilic acid (204-482-5; 121-57-3): 5 mg/kg

Bis(2-ethylhexyl)phthalate (DEHP, 204-211-0; 117-81-7): 700 mg/kg

Dibutyl phthalate (DBP, 201-557-4, 84-74-2, 93952-11-5): 90 mg/kg

5.3. List of Substances Known to Be Present in Tattoo Inks

Pigments

The choice of pigment is also a choice of the raw material for ink production. Manufactures should follow procedures of good manufacturing practice (GMP) which include the quality control in terms of purity of their raw materials. Pigments with food, cosmetic or pharmacological purity should be preferred.

Table 2: Pigments fulfilling minimal toxicological requirements [exemplary entries, need assessment]

Carbon Black, ultrapure (C.I. 77266)

Titanium dioxide, rutil (C.I. 77891)

Pigment Blue 15 (C.I. 74160)

Give your suggestions for safe pigments here.

Preservatives

Only preservatives which are not fulfilling the hazard criteria in 3.2 and 4.1 shall be used in tattoo inks.

Give your suggestions for safe preservatives here.

Other Ingredients

Only binders, solvents, humectants, extenders and surfactants and other auxiliary ingredients which are not fulfilling the hazard criteria in 3.2 and 4.1 shall be used in tattoo inks.

Give your suggestions for safe ingredients here.

[list of binders, solvents, humectants, externders, surfactants, etc.]

Known Impurities of Tattoo Inks

This non-exhaustive list may help manufactures in terms of quality control of their products and lists common impurities found in finished ink products.

[list of metals & other substances]

5.4 Methods

Release of Aromatic Amines [Details of the method procedure shall be discussed in a later phase]

In addition to the quantification of free aromatic amines, a semi-quantification of the release of aromatic amines can be used to identify the use of forbidden pigments, e.g. that cleave aromatic amines which are classified as CMR.

Release of PAH [Details of the method procedure shall be discussed in a later phase]

Since carbon black is strongly adsorbs PAH on their surface, they are limited in bioavailability and at the same time difficult to design a method for full quantification. Hence, a harmonized method using strong solvents and microwave extraction methods seems reasonable to give a maximum bioavailable PAH content.

Release of Elements [Details of the method procedure shall be discussed in a later phase]

Elements like copper and barium are part of pigments / extenders where the elements are stable bound in the structure. Hence, the maximum allowed concentration is limited to their release.

Methods to Assess the Sterility of Tattoo Inks

[is there a need to harmonize these methods? Bacterial growth methods? qPCR?]