If it is not clean it can not be sterilized

In 2003 I wrote a summary interpretation for my colleagues who were questioning a website recommending an instrument processing method that seemed unusual and unsafe. The peculiarity of this method was that tattoo and piercing equipment would be autoclave [moist heat] processed prior to cleaning.

The summary

After researching the Unimax System and exploring the supposed benefits, I propose a safer solution for tattooists [and piercers] would be to use pre-sterilized disposable [equipment, such as] tubes and pre-sterilized needle-bars, eliminating the need for a studio autoclave and the labor expense and risk for cleanup.

This appears on the surface very much a thoughtful and logical approach. The available scientific literature agrees with some of it in principle, particularly the statement though there are flaws based on several dangerous misconceptions. Cleaning contaminated tools is not possible for tattoo and piercing shops [with this method].

The main flaw in the system:

[Your system suggests that] equipment only needs rinsing or wiping off with disinfectant cloth before heat is applied.

  • Rinsing dilutes but does not remove the proteins, particularly after a long or messy procedure.
  • Wiping tools with disinfectant leaves a chemical residue as well as the proteins which is corrosive to instruments and the autoclave itself.
  • Once rinsed or wiped, equipment that is allowed to dry and have heat applied at the end of the work day compounds the difficulty of removing [coagulated] proteins.

Common bench top autoclaves are only capable of sterilizing clean or new equipment that does not have any sort of cavity, porosity, hollow spaces or tubes. A passive, type N gravity displacement sterilizer as shown and described in the Unimax system is not physically capable of cleaning the inner surfaces of the tattoo tubes reliably.

Proteins (heat resistant endotoxins) are cooked on and into scratched surfaces on tools, particularly tubes.

Protein and ink residues inside tattoo tip
Protein and ink residues inside tattoo tube
Protein and ink residues inside tattoo grip

For piercing, the same applies, though new jewelry and equipment all can be sterilized in a type B vacuum or type S positive pressure flush process autoclave, as described in the attached document.

My personal opinion:

[I] don’t bother trying to reuse anything, the evidence has shown that no piercing or tattoo equipment can be reused reliably.

 Rebuttal and discusson

Wes Woods Wrote:

I disagree with the conclusions that tattoo and piercing should dispose of used contaminated equipment instead of re-processing them for re-use.

Ben Carruth, my colleague from Piercing Experience Wrote:

You are certainly free to disagree with these conclusions. However, in order for that disagreement to have weight above and beyond a personal opinion, the argument must be refuted with the degree of care and precision with which it was made, which in this case means logically cogent presentation of principles and contextually appropriate citation of reference and research materials provided by international health agencies, independent researchers, and health regulatory authorities. Specific examples of the inadequacies of the provided counter arguments will be provided in a point for point format.

Wes Wrote:

The premises and the conclusions are parsed below followed by a rebuttal.

Argument # 1

A. Endotoxin destruction, inactivation or removal is the criteria for demonstrating the efficacy (reliability) of a sterilization process.

B. Endotoxins are not removed using gravity displacement sterilizers.

Conclusion: Gravity displacement sterilizers are not reliable.

Rebuttal Argument # 1

The inactivation of the Spore, Stearothermophilus, is the most widely accepted test for the efficacy of autoclave sterilization accepted by the CDC and OSHA not the removal or destruction of endotoxins. Depyrogenation is not a required level for an item to be considered sterile for medical tools and equipment. Argument # 1, Premise A is False, therefore the conclusion is not proved by the argument.

Ben wrote:

This interpretation of the argument is, at best, an unintentional misrepresentation. At no point is Endotoxin presence directly equated with the testing criteria for effective operation. The elimination of Endotoxins is a functional requirement of the terminal decontamination and sterilization process, as active endotoxin presence represents a potentially severe health risk. More importantly, the survival of endotoxin due to inappropriate processing indicates that more durable pathogens are potentially present: pyrogens and prions being of particular concern. [ASTM F748 covers this evaluation process]

Spore testing is the most widely accepted means of determining the efficacy of sterilization equipment to perform within its defined parameters. Spore tests are conducted to make sure that the equipment is operating up to its defined parameters: the removal of endotoxins [prior to sterilization] is a functional component of those parameters.

The issue of primary importance, however, is that which lies beyond the capabilities of the equipment in question. There is not a benchtop steam sterilization system in existence that has been rated for reliable destruction of pathogenic prions or blood-shielded enveloped viral Hepatitis C when used with methods that do not adequately remove soil such as the Unimax system. The capabilities of differing sterilization systems are closely and carefully defined, and it is the responsibility of the practitioner to use the equipment as it was designed to be used. The specific capabilities of a particular device must be assessed by a regulatory authority, such as the [FDA or the] MDA in the UK.

Wes Wrote:

Argument # 2

A.  Bench top autoclaves can only sterilize clean or new equipment.

B.Clean or new equipment means endotoxin free.

C.  Used tattoo and piercing equipment contain endotoxins.

Conclusion: Used tattoo and piercing equipment cannot be sterilized using a bench-top sterilizer.

Rebuttal Argument # 2

Clean means relatively free of gross contamination that would interfere with the sterilizing process. It is a matter of degree, not an absolute. Clean does not mean the absence of endotoxins. Premise A is false, and premise B is false. Premise C is false unless there is some study that demonstrates that endotoxins are likely to be present. The conclusion is false because sterilization is measured by spore testing not endotoxin indicators.

Ben wrote:

The parsing of Argument #2 would more appropriately be:

A.      Bench top steam sterilization equipment can only [effectively] sterilize clean or new equipment.
B.      Clean equipment is that equipment which is free of protein deposit, bioburden, or any other biological or chemical material which will impede delivery of thermal energy or presents a potential health risk in and of itself.
C.      Used tattoo and piercing equipment has been contaminated with human blood on other potential infectious materials in such a fashion that has been clinically proven to harbor culturable pathogens. A study in the U.K. demonstrated that after processing including a tunnel washer and several hydro sonic processes, a tattoo tube still retained enough active biological material to successfully culture it. Repeated cleansing processes failed to remove this material.

Sterilization equipment is tested to see if it performs according to it’s designed parameters by regular spore testing. These tests do not indicate its ability to perform beyond its designed parameters.

Wes Wrote:

Argument # 3

A.  Bench top autoclaves cannot sterilize the inside of tubes, hollow spaces, porosity nor cavities.

B.  Tattoo tubes have hollow spaces inside of tubes.

Conclusion: Tattoo tubes cannot be sterilized using bench top autoclaves.

Rebuttal to Argument # 3

Steam penetrates and reaches every available area providing massive heat transfer, including cavities, inside tubes and everywhere air reaches. Because the entire object is raised to the sterilizing temperature everything is sterile.  Premise A is false and the conclusion is not proved. The conclusion is false.

Ben Wrote:

This summary represents a misunderstanding of the mechanics of a steam sterilization process. Steam is used as a method of delivering thermal energy to the surfaces to be sterilized. Pressurization of the steam is necessary for it to reach a temperature at which it can effectively sterilize the surfaces. In a passive air displacement process, the pressurization of the chamber passively displaces the air. Anywhere that the air may be trapped (a fissure, hinge, or tube), the air itself is pressurized in such a way that steam does not reliably penetrate it. Dry air does not effectively sterilize surfaces at the same temperature that steam does.

This matter is simply not open for debate: it is a matter of clinical fact and, in many cases, legal regulation. The [En13060] MDA categorization of bench top steam sterilization equipment clearly states that type N equipment (passive air displacement) is not suitable for sterilizing instruments with hinges, tubes or lumens, cracks, fissures, other surface defects, porous surfaces (including gauze), or packaged goods. This exclusion covers near every item used in the tattooing and body piercing field.

Wes Wrote:

Argument # 4

A.  Disposing of used equipment is safer than sterilizing used equipment.

B.  Tattoo and piercing should use the safest method.

Conclusion: Tattoo and Piercing should dispose of all used equipment.

Rebuttal to Argument # 4

If a new and a used item are both sterile they are both as safe. Being “new” does not imply that it is safer. Premise A is false and does not support the conclusion that disposable tools are safer.

Ben Wrote:

Using the equipment and methods commonly used in the reprocessing of tattooing and piercing instruments, a used item will never be sterile again. A passive displacement steam sterilization process won’t sterilize the surface and the protein and biological payload cannot be removed with an adequate degree of certainty. A brief examination of the approach used by the medical community will reveal much: even with multi million dollar sterilization facilities and a large highly educated staff, most instruments that come in contact with human blood are disposed of. Those instruments that are reprocessed are of extremely high cost or are those that do not come into contact with broken skin. Your rebuttal is based on the false premise that instruments CAN be appropriately reprocessed in a cost-effective manner with reliable results. This notion has been repeatedly and consistently defeated in clinical trials and medical research over the last three decades. This is, sad to say, a typical representation of the contemporaneousness of medical knowledge in the body art community: standards that were revised in the 60’s are generally thought to be current knowledge when, of course, they aren’t. Sterilization standards and practices have been thoroughly revised since passive displacement steam sterilization was common in hospital settings, particularly in recent years with increasing awareness of retroviral and prion pathogenic behaviors and endurance.

Wes Wrote:

Thanks for giving me the opportunity to answer these objections.

Ben Wrote:

And thank you for giving me the opportunity to address these common misconceptions about sterilization and basic safety precautions.


  1. Sterilization should be safer for new, uncontaminated, properly cleaned items than reprocessed items.
  2. If reprocessing is employed, it should be done according to evidence based scientific recommendations.


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