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Toxic prussic acid is produced after laser removal - study by the Federal Institute for Risk Assessment (BfR) in Germany


For the first time, the BfR (Federal Institute for Risk Assessment) has proven that laser tattoo removal of blue ink produced several dangerous, because toxic, degradation products. Among others, benzene and hydrogen cyanide in high cell-damaging concentrations. Benzene is an aromatic hydrocarbon that is very harmful to the human organism even in small quantities. The strong carcinogenic effect leads to damage of the genetic material. Even a benzene concentration of 2 % in the air we breathe leads to death after 5 - 10 minutes. Hydrocyanic acid or cyanide is a colourless, fast-acting toxic gas that can easily enter the bloodstream through the skin due to its small molecule size. "Given that a dose of five micrograms per millilitre in the blood can be lethal, local concentrations of hydrogen cyanide of 30 micrograms are worrying," Schreiverand her colleagues said. Alarmed by the direct detection of dangerous substances, the BfR will in future increasingly investigate fission products from laser tattoo removal. Below is the commentary of the Bundesverband Tattoo e.V. with further interesting insights on the topic.   Here is the article in German (original language)

Full report on the BfR investigation

Results on tattoo removal research were already published on 5 August 2015 in the journal Scientific Reports (DOI: 10.1038/srep12915 1), which belongs to the Nature Publishing Group. The BfR has also been pointing out possible health risks from tattoos and special removal methods on its website since 2004. An English-language review article on this subject was recently published in the renowned medical journal The Lancet (DOI: 10.1016/S0140-6736 (15) 60215-X). Link to the scientific study (Scientific Report) The skin of our society is becoming more and more colourful - also thanks to a growing acceptance of skin adornments. Everyone should have noticed this by now. But with the increasing spread of tattoos, the need for motif correction or complete removal of unwanted skin stitches is also growing. To date, very little research has been done on different removal methods. Especially when it comes to health safety and possible consequences for those affected. 

Who is actually doing the research in this special area and, above all, what? 

In this case, the Federal Institute for Risk Assessment (BfR) did the research. It is a scientific institute in the portfolio of the Federal Ministry of Food and Agriculture (BMEL) and advises the federal government and the federal states on questions of food, chemical and product safety. The BfR conducts its own research on topics that are closely related to its assessment tasks. In this case, tattooing products, pigments and laser removal methods and very importantly at this point: without competing financial interests. I.e., no matter whether a positive or negative result comes out in the end. The BfR will not conceal anything from us. But also not the smallest finding.

The ruby laser

Research has now been carried out into what happens when the blue pigment phthalocyanine-blue (also copper phthalocyanine or pigment B15:3) is destroyed by laser systems (nanosecond ruby laser, Sinon and Q-switched Nd:YAG laser, Revlite SI), such as those used for dermatological treatment to remove tattoos. Why this particular blue? Well, red pigments have been researched for a long time in various places and this blue pigment with its resistance to light, acids and alkalis is very suitable for tattooing (even though it was not invented for this purpose). It is also the only organic blue pigment currently used in tattoo products on the European market. It is basically low in toxicity, but should still not be inhaled as pigment dust! Since its discovery in 1927, phthalocyanine blue has risen to become the most commonly used blue in printing inks and consumer products. The C/cyan is also found as an example on CMYK printer cartridges. Does this now mean that printing inks are used for tattooing? NO! It means that the basic pigment used is the same and, depending on the area of application, is still further processed!

Central statement of the BfR "Laser treatment produces toxic substances in dangerous concentrations"

The BfR team led by Ines Schreiver (Christoph Hutzler, Peter Laux and Andreas Luch) has now used modern analytical methods to determine the fission products that are formed during ruby and Nd: YAG laser irradiation of the copper-containing pigment phthalocyanine blue. The BfR investigations have shown that these include 1,2-benzenedicarbonitrile, benzonitrile, benzene and hydrogen cyanide HCN. (...) "We were able to show for the first time that laser treatment of a tattoo pigment in aqueous suspension produces substances in concentrations that would be high enough to cause cell damage in the skin," said BfR President Professor Dr. Dr. Andreas Hensel. Possible risks can vary depending on the size of the tattoo, pigment concentration, body site, irradiation dose as well as the wavelength of the laser used. The BfR sees a need for further research and, based on the data presented, will consider possible fission products of dyes in its risk assessment in the future. Consumers should be comprehensively informed about the possible risks of both tattoos and tattoo removal. (...) (Quotes PI-BfR from 13.08.2015)

What has the BfR done to research laser pigment treatment?

The BfR research team has simulated the laser-induced and temperature-dependent breakdown of the pigment phthalocyanine blue. In order to protect humans and animals, the BfR dissolved the blue pigment powder in water in vitro (e.g. in a petri dish or test tube, here it was cuvettes) and fired it with a ruby and a Nd:YAG laser with a total of three different light wavelengths (694nm/ ruby & 1064nm, 532nm/ Nd:YAG), tested it and measured what substances and gases were produced, for example. We can leave the BfR investigations with the Nd:YAGlaser somewhat aside here, since the two light wavelengths (1064nm & 532nm) and the selected laser parameter settings for the treatment of the blue pigment 15:3 were not found to produce any noteworthy reactions by the BfR research team. All volatile degradation products were determined by gas chromatographic (GC) separation followed by mass spectrometric (MS) analysis. As analyses by pyrolysis GC/MS (Py-GC/MS) provided further evidence for the presence of volatile and highly toxic compounds such as hydrogen cyanide (HCN) and benzene, BfR developed a dynamic headspace (DHS) method to thereby exclude any loss of such compounds during preparation and analysis. Using DHS-GC/MS in combination with two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GCxGC-ToF-MS), it was possible to detect the expected compounds very sensitively and specifically. (Quote PI-BfR from 13.08.2015) What does this mean now? I.e. if phthalocyanine blue is shot with a "hot" laser beam of a ruby laser, 1,2-benzenedicarbonitrile, benzonitrile, benzene and cyanic acid/ hydrocyanic acid, among others, can be produced! It is essential to point this out, as the presence of these substances and in these quantities can be harmful to the cells of the body!!!

How dangerous is prussic acid for humans?

What is hydrogen cyanide? Hydrogen cyanide is a colourless to slightly yellowish, flammable, volatile and water-soluble substance that smells like bitter almonds. Highly toxic, it is used, among other things, for pest control and, unfortunately, has also been used against humans on various occasions in history. However, prussic acid is also found in nature. It is found in stone fruits such as apricots, peaches, cherries and bitter almonds. It is also found in bamboo, linseed, manioc, yam and certain varieties of sweet potato. Due to a disturbance of the oxygen transport in the cells, excessive consumption leads to internal suffocation. Brain and heart cells are particularly affected by this cell death. Symptoms of acute prussic acid poisoning are shortness of breath, cramps and unconsciousness. If consumed regularly, it can lead to neurological disorders. Hydrogen cyanide is also produced as a by-product or waste product, e.g. when burning nitrogen-containing polymers/plastics or Esbit (barbecue lighter) and the classic, when smoking tobacco. To remain briefly with the deadly argument of smoking as an example - it is known that in the gaseous phase of a cigarette on average approx. 400-500 (µg) micrograms of hydrogen cyanide are released in the smoke. Since the human body is already protected from the absorption of prussic acid via natural products and in small amounts, the body's own enzyme rhodanase (thiosulphate cyanide tranferase) comes into play and plays a catalysing role in the toxin elimination of such cyanides.

Back to the ruby laser tattoo removal and the BfR study

The result of the BfR study now states that if one transfers the amounts of hydrocyanic acid HCN detected by the BfR (in vitro) to the situation in the human body (in vivo), HCN concentrations of up to 30 (µg) micrograms per millilitre (ml) could arise in certain and well perfused tissue layers through ruby laser treatment. This could lead to possible health risks and cell damage. And as the BfR itself says, especially when extremely large tattoos are irradiated with a ruby laser at once (e.g. > 500 square centimetres).

Comment of the German Federal Association Tattoo e.V. on the BfR investigation

Assessment of the laser used

It is good that finally someone is doing it who is independent of industry or private financiers. Unfortunately, the ruby laser selected by the BfR is technically and from our own point of view not quite up to date in laser medical technology. Ruby lasers are now only rarely and very sporadically used to remove tattoos, but they can certainly still be found in one or two practices. For good reason: the ruby laser is really well suited for a wide variety of indications and lesions of the skin! In addition, however, the question arises for us, among other things, with which energy densities were actually worked, at which light pulse speed. According to the publication of the BfR study results in Scientific Reports, 3 laser shots with the ruby laser (Sinon®) with the parameters 5 joules/ qcm were fired at the blue pigment with a laser spot size of 5 mm and the wavelength 694nm. The choice of spot size and energy density has a massive influence on the penetration of the laser beam into the natural skin. What remains unconsidered is the light pulse speed, which the laser manufacturer Sinon® specifies for its ruby laser as 20ns/nanoseconds. This is further than beyond the current state of the art and, in our view, is more likely to cook the pigment instead of shattering it. The BfR study speaks of the breakage of the pigment particles by an induced steam-carbon reaction due to temperatures of up to 1000 degrees Celsius. We call it burning. Modern nanosecond lasers work under 8ns and picosecond lasers (i.e. even faster) are on the rise.

Hydrogen cyanide is produced by laser bombardment and 800 degrees Celsius

Question on this: Do the resulting cleavage products of the treated pigment change when photomechanical/photoacoustic laser systems are used? It would be important to know whether the BfR investigation involved single shots or whether the 3 shots were fired in direct succession. As a rule, the Q-switched pulse velocity often changes to the disadvantage in a direct shot sequence. In addition, it is noticeable in the measurement diagrams that measurable relevant factors with regard tohydrogen cyanide HCN only occur at temperatures above 800 degrees Celsius. That is, when the pigment B15:3 carbonises. The light temperatures are massively influenced by the laser pulse properties. We urge you to bear this in mind! The BfR also explicitly points this out in the associated article.

Nobody knows exactly how dangerous the respective pigment colours are with which laser

Another consideration is why the pigment 15:3 reacted so badly to the light wavelengths of the Nd:YAG laser (Revlite SI), but blue tattoos can be treated with it in the real world: There is, as already described above, a difference between pigment 15:3 and a resulting TATTOO medium. The latter is, among other things, further processed in order to be used for tattooing. Depending on the size of the pigment, the carrier materials used and the admixtures, some variants of the tattoo medium react to the laser impulse of the Nd:YAG and can be shattered for colourdegradation. We are not yet able to answer the actual reason for this.       How much pigment was actually shot at once? The measurements were made with amounts of 0.2 - 2.5 mg, but on which surface? According to the literature, up to 9mg of pigment per cm2 of skin is recorded on average as a tattoo. Within this square centimetre there are other substances that can influence the laser pulse. In addition, tattoo pigments agglomerate in the skin and are certainly not always uniformly distributed. In succession to the removal treatment, the laser beam must penetrate deeper and deeper into the skin in order to hit tattoo pigments. So it also depends on the skin thickness, skin type and body part. The laser spot size of 5mm chosen by the BfR is already quite large and in professional practice is only chosen for the 3rd, 4th, 5th treatment repetition. The laser spot size influences the penetration depth of the laser beam into the skin. Conclusion: 5 mm laser spot size, 5 joules/sq cm energy density at 20 ns laser pulse is, in our view, already very negatively result-oriented selected. To explain it a little more metaphorically: It is like turning an iron to full temperature, putting it on a silk shirt for 10 minutes and being surprised that there is fire damage.

 The lethal concentration 2 mg/ kg body weight

The lethal (fatal) dose of hydrocyanic acid HCN in most animal species is around 2mg (concentrated) per kilogram of body weight (2000 µg HCN per 1,000,000 µg body weight) or a 50 ppm (0.005%) concentration in the air. So what does an HCN concentration of up to 30 (µg) micrograms per millilitre (1 ml or 0.001litre) from the BfR test result mean? Okay, not good - it can lead to cell damage - we understood that too! The BfR has topoint this out and we do!  As a tip: professional laserologists should not treat 500 sq. cm large colourful tattoos in only one session. Today, blue tattoo pigments are usually treated with an alexandrite laser, but high-energy and fast Nd:YAG lasers can also shatter certain types of blue tattoo pigments. Research, such as by the BfR, is still pending on this. And one more question at this point: If we understood correctly, the BfR directly researched the pigment B15:3 using the ruby laser treatment!? How big were the pigments actually? We didn't find anything about this in the article on the study!? Why wasn't it better to use a blue tattoo medium in which the pigment was further processed, i.e. more real conditions? The pigment B15:3 will probably never be found alone in the skin. Carriers are used in the production of tattooing products. In our opinion, this is not taken into account. (Of course - in order to remain independent of tattoo product manufacturers as a federal institute in the investigation. But in our opinion this is unnecessary, since someone also built the ruby laser). Judging by the news headlines of the past few days, many people are jumping at the BfR result of the nanosecond ruby laser treatment for tattoo removal of phthalocyanine blue, which is supposedly risky and a health hazard.  From our point of view: basically top and research is always good - especially if you talk about it!!! Laser tattoo removal is not a recreational sport, but a cosmetic-aesthetic intervention in the personal body of a tattoo wearer. We hope that one or the other tattooed person or future tattoo wearer will give more thought to their motif and tattoo means than seemed to be the case so far. We hope that this topic will raise awareness a little. We have often read that "tattoo removal is not without risk". It's true!!! Just like tattooing is too! That's why we advise everyone to go to a tattoo studio and see a tattoo professional, to get extensive advice and to think about your own choice of motif in advance. Then maybe we won't get to know each other! Above all, this "youth sin" will not happen and the tattoo will keep its promise: for eternity! Think before you ink! FSK21!

Support your local tattoo hero:

If you want to support the guild of professional tattoo artists, you should visit the website of the Bundesverband-Tattoo e.V. and become a member. It costs the customer nothing and is not a subscription - but supports the tattoo professionals immensely with every single vote. The D.O.T. e.V. and ProTattoo e.V.should also become your cornerstones if you want to get professionally decorated. A lot of information helps a lot!  If you have any questions, please feel free to contact us at any time via info@doctattooentfernung.com or 030-80105999. Source Article Quotes Schreiver, I. et al. The formation of highly toxic prussic acid on ruby laser irradiation of tattoo pigment phthalocyanine blue. Sci. Rep. 5 , 12915; doi: 10.1038 / srep12915 (2015). Source information:

1. Federal Institute for Risk Assessment (BfR), Institute for Chemical and Product Safety, Max-Dohrn-Straße 8-10, 10589 Berlin, Germany.

Ines Schreiver, Christoph Hutzler, Peter Laux & Andreas Luch

2. Evangelisch-Elisabeth-Krankenhaus, Clinic for Laser Medicine, Lützowstraße 24-26, 10785 Berlin, Germany

Hans-Peter Berlin CH, IS, PL and AL developed the study. IS and HPB performed the experiments. IS, CH, PL and AL critically reviewed the data and wrote the manuscript. CH and AL supervised the entire study, including planning, execution and interpretation of the instrumental analysis and in vitro experiments. Conflict of interest The authors declare no competing financial interests. Science Tattoo Removal Laser/Technology

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11 November 2022 in Background information

Position of the authorities on cosmetic tattoo removal (SKINIAL) in the individual countries.

Adventurous rumors keep circulating about this. We are in contact with the authorities in all the countries mentioned and explain the partly different points of view.   Unlike medical products, cosmetic