Ultra-V tested by UCLH, exposed as fraud!

Breaking news – in a Journal of Hospital Infection article published August 16th, Prof Wilson of UCLH shows that the Ultra-V UV room disinfection system takes a whopping 1 hour and 19 minutes to achieve even BASIC levels of decontamination, requires multiple re-positioning of the unit during the cycle, does NOT decontaminate shadowed areas, and is particularly ineffective against C. difficile spores. (log 0.1 to log 1.1)

MEANWHILE – Hygiene Solutions claim a 20 minute cycle time, NO re-positioning, and log 4 to 6 efficacy.



Fentiman denied employees PPE, gas detectors.


Gordon’s Story

Gordon Cunningham started working for Hygiene Solutions early in 2013, building and servicing the Deprox machines, as well as operating the system in hospitals across the UK. He noticed that at the end of a decontamination process, the treated rooms often still had a visible white mist in the air, although the Deprox remote control light indicated that the room was safe to enter. He raised his concerns with company directors Rick and Mark Fentiman, but was told that there was nothing to worry about and that the process was entirely safe. Nonetheless, he requested a respirator and a hydrogen peroxide (H2O2) gas monitor (Draeger) to protect himself when using the Deprox, but his request was ignored.

Gordon, a non-smoker who keeps fit by running and triathlons, began to experience a tender sensation in his throat after being exposed to the Deprox residual vapour. These symptoms progressed to an asthma like feeling of a constricted airway and a hoarse cough.

The business owners, Rick and Mark Fentiman insisted that re-entering a treated room was safe, as long as the H2O2 level was below 5.5ppm. (In fact, the safe exposure level is 1ppm)

Gordon then spoke to the chemist who was working on the Deprox project, David Sempere Aracil. David told him that he should not be entering rooms at 5.5ppm.

In June 2014, Gordon was asked to spend 3 days operating the Deprox system at the Luton and Dunstable Hospital. Six months had passed since he requested a respirator but his request had not been responded to. When re-entering the rooms, he would try to cover his mouth and get the windows open as quickly as possible, to minimize his exposure. Gordon noticed one of the technicians had a new Draeger H2O2 meter, and he asked how it was operated. The technician explained how to use the meter, and how to set it so that it would sound an alarm buzzer until the gas concentration had dropped to a safe level. Gordon had done some research, so he knew the safe level was 1ppm. Gordon took the Draeger to Luton with him.

On Monday June 2nd 2014 Gordon had two rooms for Deprox treatment at the Luton and Dunstable Hospital. The first room was the equipment library. He set up a Deprox unit in this room, and 1 ½ hours later the green light on the Deprox remote control lit, indicating that the room was safe to enter. He un-taped the door, and followed the instructions from the technician, used the Draeger to check the gas concentration – it was 7.8ppm. Gordon left the Draeger in the room and taped the door closed again. Further to the technician’s instructions, there will be a continuous alarm tone until the safe level of 1 ppm was reached, the room will then be safe to enter.

Later in the day, some hospital staff wanted access to the library to get some equipment. Gordon explained that it was not safe to enter until the Draeger had indicated a safe level.

Four hours after the process had completed, the room was still inaccessible, as the Draeger was still giving an alarm tone. Gordon was summoned to the office of Camilla, head of Domestic Services. Camilla demanded to know what the problem was in the library, pointing out that in the Hygiene Solutions Deprox literature the “deactivation” cycle is only 90 minutes, and that they never normally had to wait longer than that. Gordon explained about the Draeger, and that the equipment library was not yet a safe environment.

A little later Gordon was summoned to the office again, and told that “Your boss, Mark Fentiman is on the phone, and says you are to take the Draeger out of the library immediately.” Mark Fentiman then phoned Gordon directly and ordered him to remove the Draeger and open up the library to the hospital staff.

Gordon un-taped the door and entered the room. The H2O2 level according to the Draeger was at 4.3ppm, well above the safety limit. Gordon removed the Draeger and opened up the room, telling the hospital staff to wait as long as possible to let the gas disperse.

Hygiene Solutions told the hospital that Gordon was using equipment that was not calibrated, and that he had not been trained on, and that the gas levels in the room had been completely safe. In fact, the meter was freshly calibrated, and Gordon has copies of the all calibration certificates to prove it.

Other staff members, including Tim Murrell, the Deprox patent holder, witnessed Mark Fentiman’s fury at the news. Tim said he had “never seen someone so angry” as when Mark found out that Gordon had taken a Draeger to Luton.

Gordon lost his job that week. The other staff at Hygiene Solutions were told it was because he used an uncalibrated meter without permission.

Gordon still suffers from respiratory problems as a result of his exposure to the Deprox fog. It may well be that inhaling the combination of hydrogen peroxide and silver nitrate has caused irreversible damage to his trachea and lungs.



Update: http://www.deproxfraud.info achieved 40,000 views as of this afternoon, and now ranks higher on Google than Hygiene Solutions’ own website!

Fentiman’s Toxic Legacy

After two years of misinformation, deceit and outright lies, fake “Cambridge graduate microbiologist” Rick Fentiman has to admit that his Deprox process leaves hospital rooms and equipment contaminated with highly toxic silver nitrate dust. A recent investigation at the University College London NHS Trust revealed the following figures:

  • Silver Nitrate content of Deproxin solution: 10 – 25mg/l
  • Silver Nitrate deposited on room surfaces after a single cycle: 1.5 – 2.5mg/m2

An independent test of the same parameters by Butterworth gave similar results:

  • (Deproxin) Silver expressed as Ag (by Plasma Emission Spectroscopy) 51.0mg/l
  • (Deproxin) Nitrate expressed as NO(by ion chromatography)  35.1mg/l

Surface deposits after single cycle:

  • (Surface) Silver expressed as Ag (by Plasma Emission Spectroscopy) 2.5mg/m2
  • (Surface) Nitrate expressed as NO(by ion chromatography) 1.8mg/m2

Silver nitrate is persistent in the environment, and will build up cumulatively each time a room is processed. The permitted level of silver nitrate dust in the air is vanishingly small. The legal maximum is 0.01mg/m³ –  250 times this amount of the chemical is deposited on each square metre of surface per process! 

This presents a particular danger to hospital staff making up the bed after a Deprox process – laying down the mattress and placing sheets will disturb clouds of the fine dust at very hazardous levels. Staff should certainly be provided with appropriate respiratory equipment for this task, and silver nitrate dust levels should be monitored before readmitting patients. 

Rooms that have become heavily contaminated by multiple processes may need decontaminating by Hazchem professionals.

Silver Nitrate deposits at the Royal Liverpool Hospital


Isolation rooms at the Royal Liverpool University Hospital have become so heavily contaminated with silver nitrate that patients have complained, mistaking the black deposits on the windows for dirt. Director of nursing Lisa Grant admitted that the Hydrogen Peroxide Vapour (HPV) bio-decontamination system leaves a “sterile residue” but was apparently unaware that it is silver nitrate. The photo above was submitted to The Liverpool Echo by a patient who attempted to remove the chemical with a tissue. There is enough silver nitrate on the tissue to cause unpleasant chemical burns to the skin. Even more seriously, the AgNO3 dust levels in the room must have been far in excess of the legal maximum, which is an invisibly small 0.01mg/m³ – that’s 1/100,000th of a gram per cubic metre of air.

Rick Fentiman

Rick Fentiman claims to be a "Cambridge graduate microbiologist"

Fentiman’s UCLH Hoax


A letter published this week by Prof. Wilson of UCLH finally proves how Hygiene Solutions’ (Deprox) director Rick Fentiman cheated both the UCLH and rival HPV system manufacturer Bioquell Plc, in a widely publicized comparative test in 2015. The results of this test apparently demonstrated that the Deprox, vapourising a 5% Hydrogen peroxide solution had identical germicidal efficacy as the Bioquell system vapourising 35% hydrogen peroxide solution.

I published an article in 2016 in which I analyzed the test results as published by Professor Wilson and colleagues in the Journal of Hospital Infection, and concluded that Fentiman had in fact filled the internal tank of the Deprox machine with a 35% solution prior to the test. New data published in the letter proves this claim beyond reasonable doubt.

In Wilson’s original test, neither the aerial concentration of H2O2 vapour , or the concentration of the liquid solutions was  measured.

In response to widespread concern and comment as to the rather surprising results obtained, Wilson recently again obtained the use of a Bioquell and a Deprox system and measured the concentrations of both the liquid and aerial vapour phases throughout their test cycles, as detailed in this week’s letter.

The Deprox was using 5% H2O2 solution, and produced peak vapour concentrations of 29 to 46ppm. The Bioquell machine was using a 35% solution, and produced 450 to 640ppm of vapour.

The maximum aerial concentration of H2O2 that can be generated is limited by the concentration of the original solution. Henry’s law can be used to prove that about 50ppm is the maximum sustained aerial concentration that can be generated from a 5% solution. The figure of 46ppm for Deprox from Wilson’s retest of the machine is thus exactly what would be expected.

In the original comparative test, both the Deprox and the Bioquell systems demonstrated practically identical efficacies of log 5.1 for spores and log 6.3 for vegetative bacteria. A very large number of biological indicators of several species were used over multiple tests, and no significant difference in performance between the two systems was found.

Therefore, inescapably, both systems must have generated the same aerial concentration of H2O2 vapour, and that must have been in the region of 400 to 700ppm. (There are numerous published papers demonstrating a log 6 efficacy for HPV systems using 30-35% H2O2 solutions)

It is physically impossible to generate anything close to these levels of vapour by evaporating or aerosolizing a 5% solution. Quite apart from Henry’s law, the volume of water that would have to be evaporated along with the H2O2 would quickly push the relative humidity to saturation, and prevent further evaporation from taking place.

Therefore, in the original comparative tests as published in the Journal of Hospital Infection, the Deprox was NOT running on a 5% H2O2 solution as claimed, but on a 35% solution, the same as the Bioquell system.

How then was this deception accomplished?

There are some aspects of the way in which the original UCLH tests were conducted that  are very suggestive:

At the time of the tests, Hygiene Solutions had a contract with UCLH, and had 4 Deprox machines permanently on site, which were operated daily by Hygiene Solutions employees. UCLH had a definite rule that the equipment was not to be operated by their staff – hence no UCLH staff were trained in the use of the equipment.

The paper states:  “The HPS1 unit was operated by a trained engineer (Bioquell), while the HPS2 module was operated by hospital staff following training by a dedicated member of the issuing manufacturer (i.e. Hygiene Solutions).”

I have two independent witnesses that the two Deprox machines were used in the trial were not the machines already on site, but were specially prepared at the Kings Lynn depot, with all new piezo discs and calatytic deactivation media. The machines were driven up to UCLH personally by Rick Fentiman, who stayed for the duration of the tests then drove the machines back to Lynn. Apparently no other Hygiene Solutions staff were involved. The “dedicated member” therefore was Rick Fentiman, and he instructed and supervised some unidentified member of the “hospital staff” in the operation of the equipment “on the spot”.

The paper says: “However, during this study, both parties provided storage of equipment and hydrogen peroxide stock solutions off-site.” In the case of the Deprox units, this was  the large van in which they were transported. Clearly then there would have been opportunity for Mr Fentiman to have filled the internal storage tank of the test machines with a 35% solution and disposed of or diluted any residual fluid after the test, without either his own employees or the UCLH staff being aware of the substitution.

It is pertinent that (unknown to the UCLH) the Deprox has a substantial internal storage tank, of about 8 litres capacity.


Illustration from the Deprox patent.

The evaporation unit draws from the bottom of this tank, and the 2 litre Deproxin refill bottles trickle feed in to the top of the tank. I assume that for the sake of authenticity, a genuine Deproxin refill was inserted in to the top of the machine for the tests, hence even if Prof Wilson had tested the concentration of the fluid, he would have found it to be as stated. As concentrated H2O2 solution is substantially denser than water, a trickle of dilute solution in to the top of the tank would have no significant effect over the course of a few cycles of the machine.


Deprox salesman Tom Lister stalls when faced with a direct question about the UCLH tests. The machines had been filled with a 35% hydrogen peroxide solution, where UCLH were told it was a 5% solution. Tom knows this, and his guilty conscience shows very clearly in his body language and facial expressions. Rather than answer he says “Where did you say you were from?” although I had just told him, and was wearing a badge with the answer in large type!


Wilson exposes Deprox fraud!

Deprox Hygiene Solutions

In a letter published today in the Journal of Hospital Infection, Professor Peter Wilson and colleagues report on their retesting of the Deprox (Hygiene Solutions Ltd) HPV decontamination system. The retesting was in response to concerns widely raised that the earlier tests of the system, which purported to give a log 6 efficacy, were the result of the manufacturer misrepresenting the concentration and/or constituents of the Deproxin solution.

In brief, the retest reveals the following:

  • The efficacy of the system, when using the correct 5% H2O2 solution, is around log 4 – similar to other, much less expensive fogging systems on the market. Hygiene Solutions Ltd will now be taxed to explain why on the initial test by Prof. Wilson, a log 6 efficacy was found. This 100 fold drop in efficacy comes between the first test series, in which the solution concentration was not checked, and the second series in which the concentration was independently measured. It seems highly likely that in the initial test series, the Deprox was running on a 30% H2O2 solution, rather than a 5% H2O2 solution as claimed.
  • The aerial H2O2 concentration on re-entering the room at the end of the cycle was 3.3ppm which is in excess of both short term and long term H2O2 exposure health limits. This is in spite of a hasty retrofit of catalysts to the whole Deprox fleet, and the manufacturer’s claim that their system monitored the H2O2 levels, and would only allow re-entry when the level was below the 1ppm safety standard.
  • Deproxin is confirmed to contain 10-20ppm silver nitrate, and this is indeed deposited on surfaces in the room, and may well be a contributor to the efficacy achieved. Hygiene Solutions informed the HSE over a year ago that Deproxin does not contain silver nitrate. This has now been exposed as untrue – and raises the question as to whether it is currently legal to sell or use the Deprox system.
  • Poor efficacy results for two more sheltered locations is attributed to inhomogeneous vapour distribution, due to inadequate circulation of the vapour. This raises serious doubts as to Hygiene Solutions’ claims that the Deprox will decontaminate “inside small crevices and complex equipment”

It is very much to the credit of Professor Wilson and colleagues that they have thoroughly retested the system in response to widespread concerns. It is sad that commercial interests would abuse the trust and confidence of highly qualified academics in this way by misrepresenting the basic test parameters.

For those without access to the Journal of Hospital Infection, I have reproduced the letter below, and a PDF is downloadable here.


In response to the letter from Dr Singh commenting on our paper.[1], [2]

The objective of our study was to evaluate the reductions in environmental contamination during in-use operation of two commercially-available hydrogen peroxide whole-room disinfection systems.2 Both manufacturers agreed test parameters prior to the trial to ensure methodology followed manufacturer instructions. Our findings suggested similar efficacy of the two systems against both surface contamination and biological indicators of common pathogens. Inocula used on the indicators far exceeded the likely levels seen in the environment.

Additional studies were performed as part of the original work using the same methodology with four strains each of MRSA, Klebsiella pneumoniae, Clostridium difficile spores and Acinetobacter baumannii. Three HPV decontamination cycles were evaluated for each system. Of 305/320 samples, >4-log10 reduction was achieved.

Aerial concentrations of hydrogen peroxide and relative humidity were monitored continuously during a further 6 cycles of both systems using a sensor (C-16 Portasens II Gas Detector; Analytical Technology Inc., Collegeville, PA, USA). In addition, horizontal surfaces in the near-patient vicinity were swabbed and analysed to detect fallout of silver and nitrate at the end of HPV decontamination cycles (n=3). Surfaces were swabbed and analysed for silver by titration (Silver Test Kit, DTK Water, Wellingborough, UK) and nitrate using Quantofix semi-quantitative test strips (Macherey-Nagel, Düren, Germany).

For the Deprox (Hygiene Solutions, King’s Lynn, UK) system, peak aerial values of 29-46 ppm hydrogen peroxide were achieved with similar bacteriological efficacy as other cycles. The mean level at the end of the cycles was 3.3ppm for 41.8% (30.8-58.1%) mean relative humidity at start of cycles. Silver and nitrate were detected on surfaces at 1.5-2.5mg/m2 following cycles with the Deprox system.

For the Bioquell Q10 system with the R10 aeration unit (Bioquell, Andover, UK), the peak aerial levels of hydrogen peroxide were 450-640ppm. The mean level at the end of the cycles was 0.0ppm with starting mean relative humidity 42.5% (34.5-49.7%). No silver or nitrate was detected on surfaces following cycles with the Bioquell Q10 system.

The aqueous concentration of hydrogen peroxide in a Hygiene Solutions cartridge (Deprox) tested on one occasion at the point of insertion into the machine was 5%. Nitrate was detected in the aqueous solution at 10-25mg/L. The aqueous hydrogen peroxide concentration in the Bioquell Q10 cartridge (Bioquell HPV-AQ) was 35% and no silver or nitrate was detected.

Dr Singh suggests C. difficile spores (but not the other organisms) persisted underneath the bed and on the window frame after decontamination using the Deprox system. The persistence of spores may have been minimised during the Bioquell Q10 cycles by the inclusion of an oscillating fan to facilitate aerial distribution and aid breakdown of hydrogen peroxide vapour.

As Dr Singh suggests, settling of active silver onto biological indicator coupons during a cycle of aerial HPV decontamination may have contributed to the bactericidal/sporicidal activity of the Deprox system. However further studies would be required to elucidate its role.

Profiteers playing with fire..

Deprox PBCC

(OK, it’s off topic, but this is another deeply disturbing example of profits being put ahead of safety, and commercial exploitation of weak or inadequate government  regulation)

Dr Ecosse

Fairview Architectural, a Unispec brand whose UK distributor is Valcan Ltd, posted a news item bragging that they secured the contract to replace the burnt out polyethylene core cladding responsible for a terrifying 2014 tower fire in the Lacrosse Apartments in Melbourne, Australia.


Incredibly, in spite of this first hand experience of the danger of polyethylene cored panels, the same company supplied their polyethylene core Vitrabond panels to the Evenlode and Windrush residential tower blocks in Oxford UK, through its UK office, Valcan Ltd. – and bragged about that too!


According to a recent article in The Telegraph, the polyethylene core burns like petrol:


Now, according to the Oxford News;

“FEAR and bewilderment has gripped families in Blackbird Leys following the revelation that the estate’s two towers are covered in cladding deemed a fire risk.
On Monday it emerged that samples sent by Oxford City Council to the Building Research Establishment had failed fire safety tests and will now be replaced.
It follows more than 12 months of refurbishment work on Windrush and Evenlode Towers as part on an ongoing £20m project to improve Oxford’s tower blocks, in which the cladding itself had cost £1.4m to install.”


However every cloud (of smoke) has a silver lining. Architectural cladding manufacturers have never had such a profitable year in prospect! Tens of millions of pounds worth of polyethylene core facades will have to be ripped off and replaced by fire resistant versions across the UK – BY THE SAME COMPANIES THAT SUPPLIED THE SUBSTANDARD MATERIAL IN THE FIRST PLACE.
Let’s hope that Oxford City Council ensures that the supplier responsible for this expensive disaster doesn’t get to profit from it for a second time.