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UK’s Regulatory Agency turns a Blind Eye to Ethylene Oxide on Test Swabs

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Responding to a request under the Freedom of Information Act mid-last year, the Medicines and Healthcare products Regulatory Agency (“MHRA”) – the organisation responsible for regulating medicines, medical devices and blood components for transfusion in the UK – demonstrated little interest in the use of ethylene oxide to sterilise test swabs being used en masse and repeatedly by the UK population.

There are three common methods of sterilising medical devices such as test swabs: two methods of radiation (“R”) and ethylene oxide (“EO”).  In May 2021, in response to a request made under the Freedom of Information Act (“FoI”), the MHRA showed poor knowledge and little interest in taking responsibility for the amount of EO residue that may be transferred to people when taking Covid tests.

EO is used as a sterilising agent for medical supplies and foods, as a fumigant and as an insecticide. Exposure to this substance is highly irritating to the eyes, skin and respiratory tract, induces nausea and vomiting and causes central nervous system depression. Ethylene oxide is mutagenic in humans and chronic exposure is associated with an increased risk of leukaemia, stomach cancer, pancreatic cancer and non-Hodgkin lymphoma.

ISO 10993-7:2008 ‘Biological evaluation of medical devices — Part 7: Ethylene oxide sterilization residuals’ states that EO is known to exhibit a number of biological effects which include irritation, organ damage, mutagenicity and carcinogenicity in humans and animals, and reproductive effects in animals and that exposure to EO residues should be minimised.

Purple Lion Project: All About the Nasal Swab, 18 May 2021 (8 mins)

If the video above is removed from YouTube, you can view it HERE.

The International Organisation for Standardisation browsing platform states “only informative sections of standards are publicly available” for ISO 10993-7:2008. Tolerable contact limits (“TCLs”) and exposure limits are given in sections and annexes of the ISO which have not been made publicly available – TCLs are the concentration limits to avoid potential irritant effects of EO residues on EO-sterilised medical devices.  So, we searched other websites to get an indication of what the TCLs and exposure limits are.

In the year 2000 a directory of medical device suppliers, QMed, published an article which stated that “to address the cumulative effects of multiple use (more than 100 times in a lifetime) or of neonatal use of devices in the limited-exposure category,” residue limits for the “prolonged category” should be applied –  2mg per day for the first 30 days and no more than 0.1 mg EO be delivered to the patient from day 31. But noted the 0.1mg limit from day 31 “will likely change in the revision of ISO 10993-7.”

Steris, an Irish-domiciled medical equipment company specialising in sterilisation, states on their website that according to ISO 10993-7:2008/(R) 2012: “limited” use of a device is less than 24 hours; “prolonged” use is 24 hours to 30 days; and, “permanent” use is more than 30 days.  And, the EO exposure limit for: “limited” use is 4mg in 24 hours; “prolonged” use 60mg over 30 days (2mg per day); and “permanent” use 2.5mg over a lifetime.

FullFact, which is likely still Facebook/Google funded and who – as Facebook recently admitted of their “fact checkers” – are merely giving their opinion, wrote an article to dismiss a claim circulating on social media that the packaging of lateral flow tests from the NHS was deliberately changed to remove reference to EO – which it admits was the case but in their opinion was to avoid confusion as to which parts of the test kit were sterilised with EO rather than as an act of deliberate deception.

Although FullFact’s article is attempting to downplay the dangers of EO it is worth reading, if you can ignore their obvious corporate bias, as it contains links to a number of interesting points about EO.  One such link is a response from the Welsh Government to a FoI request.  The Welsh Government stated that “manufacturers have confirmed that 1-2μg/g of ethylene oxide is used in the swabs.”

Let’s assume a test swab weighs 1 gram.  It is likely a swab weighs half this but there are number of broad assumptions and guesses that follow that more than compensate for this.  That would mean each swab contains 0.5-1 microgram of EO.  Steris states the TCL is 10μg/cm2.  So, it would seem the EO in swabs are below the concentration for any potential irritant effects in the nose or throat for any single testing event.  In other words, we would not notice an irritation to the swabs when they are in contact with, for example, our skin, nose or mouth.

However, regarding residues of EO the test swab leaves behind it may be more difficult to establish and will require laboratory testing or research to be carried out.  In the absence of scientific research being conducted we will attempt to reason out if this is something, justifiably, the MHRA should be investigating.

Let’s consider a school age child, say 11 years old, who should be exposed to a maximum of 2.5 milligrams of EO in their lifetime, say another 70 years based on the average life expectancy in the UK.  For simplicity’s sake we will ignore any other sources of EO exposure, such as medical interventions or hospital visits etc – which of course is unreasonable – and assume Covid test swabs are the only EO exposure the child will experience during their lifetime.

And let’s assume each test swab inserted in the child’s nose or throat leaves a residue of 0.25 micrograms of EO, in other words half of the lower estimate of what is on the packaged swab is transferred as a residue.  Assuming a swab of both the nose and throat is taken that would mean 0.5 micrograms EO residue for each Covid test the child takes. 

Assuming the safe level of EO exposure over a lifetime is at 2.5 milligrams is correct, this would equate to 5,000 tests (2.5/0.0005).  If Covid tests were taken at an even rate throughout the remainder of the child’s life, 70 years, this would be only 71 Covid tests per year or just over one per week.

How many tests has your child had over the last two years?

“Limited contact” level set by the manufacturer – why is the MHRA not setting the level of contact that translates as “limited” and, ultimately, safe?

Additionally, earlier in their response MHRA said “the manufacturer is responsible for testing the amount of ethylene oxide left on the device after sterilisation to ensure that the residue left is below the allowable limit.” 

Nowhere in their response did MHRA indicate what safe exposure levels they had set, that the MHRA were aware of what the ISO limits were and that the MHRA conducts tests to confirm what the manufacturer claims as the amount of EO left on their device is in fact the case.

Does it feel as if the MHRA is taking responsibility when it comes to regulating medical devices and safeguarding the public’s health? No, it feels as if the MHRA is simply shuffling papers.  Its response does not instil confidence that it’s taking its duties seriously, duties which the public – not the manufacturing or pharmaceutical companies – pays them to perform for the sake of the public’s health.

In the video below Hugo talks about polyethylene glycol (“PEG”) found in Covid injections and EO in Covid test kits.

Hugo Talks: Ethylene Oxide Part 2, 20 April 2021 (4 mins)

Further resources:

UK’s Regulatory Agency turns a Blind Eye to Ethylene Oxide on Test Swabs
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5 months ago

‘..Let’s look at some of the basic Science Facts on testing:

  1. A nasal swab test is a PCR test
  2. PCR tests are for rapid DNA replication
  3. Coronavirus does not contain DNA, only RNA
  4. A PCR test cannot replicate RNA and therefore cannot detect coronaviruses

So, what are they really testing and what are people testing positive for?
In our view, there NO SCIENTIFIC basis to use a nasal PCR swab to test for COVID19. …’ (Principa Scientific International)

For animals’ genetic testing to put the swab between one side inside their mouth and that side’ row of teeth and move gently is enough. So why we exactly instructed to rub our tonsils and almost our brain with it?

Do the test at home, average microscopes are rather cheap 30-100. Spit in a small bowl, move the swab gently in your saliva for the time required, don’t even rub the glass, then have a look of the remaining stuff in the bowl…. Those fallen rigid looking white threads easily can pierce the soft flesh and stuck. Why this cruel, dangerous method is needed? Anyone can explain?

‘…Johns Hopkins researchers take inspiration from parasitic work for medicine delivery“Theragrippers” are tiny, shape-changing machines that deliver medicine efficiently to the GI tract… ” ‘ – or any other tract?

5 months ago

[…]–lockdown-:b […]

5 months ago

[…]–lockdown-:b […]

Paul Cardin
Paul Cardin
5 months ago

I’ve enquired extensively on this important subject since May 2021, been fobbed off, and witnessed successive failures from my local public health director, my local MP, Angela Eagle, Gavin Williamson and Lord Bethell who speaks on Social Care in the House of Lords. My concern is a potential cumulative build-up of ethylene oxide inside children’s body tissue and bloodstreams.

These officials have assured me that levels of EO are within acceptable limits, however, on checking the relevant British and international safety standards – ISO 10993-7 – Lateral Flow Antigen test kits are not featured. Further to this, before these kits were ever placed into the public realm, government-appointed scientists working at Porton Down ran them through tests which were rushed, cursorily done, functional, and nowhere was the key area of public safety explored or analysed. The following blog post and others contained within go into much greater detail:

Last edited 5 months ago by Wirral In It Together
Paul Cardin
Paul Cardin
Reply to  Rhoda Wilson
4 months ago

Hi Rhoda,

I’ve only just caught up with your reply 21 days later. Yes, thanks for the offer. I would like to write the article and be named. I’ll send an email to with my email so you can get in touch,



5 months ago

[…] UK’s Regulatory Agency turns a Blind Eye to Ethylene Oxide on Test Swabs […]

Paul Cardin
Paul Cardin
5 months ago

Have just searched the relevant International Standard ISO 10993-7 here:

Microsoft Word – C034213e.doc (

…and found nothing for the following keyword searches:

lateral flow

3 months ago

[…] 1h26min43s : Présence d’oxyde d’éthylène dans les écouvillons des tests PCR : […]