Wednesday, November 14, 2018

Method Comparison: Formaldehyde

Formaldehyde has many properties which make it a highly effective sterilizing agent. The earliest reports of its use as a fumigant date back to the 1880s, and it has remained the chemical of choice for laboratory fumigation for decades. Like chlorine dioxide, formaldehyde is a true gas that has excellent distribution and penetration completely filling any area it is injected into. However, to be effective, formaldehyde requires long contact times (on the order of 6-12 hours), and the gas requires a post-exposure neutralization step after the contact time is completed. This neutralization step leaves residuals which must be cleaned after the decontamination.

Formaldehyde usage may be simple and inexpensive, but concerns exist over its toxicity and carcinogenicity. In fact, the European Union has banned its use in certain applications. Formaldehyde is a toxic chemical that is classified as a Group 1 human carcinogen. Largely for these reasons, formaldehyde is being used less and less for decontamination.  Gaseous chlorine dioxide is being chosen by many facilities as a safer and more effective fumigation alternative.

Learn more here from a 2011 study that compared six different microbial fumigation methods with the goal to evaluate the biocidal efficacy of alternatives to formaldehyde.

Friday, November 9, 2018

Can You See CD?

Chlorine dioxide (CD) is a greenish-yellow gas with a chlorine-like odor recognized since the beginning of the 20th century for its disinfecting properties. At every installation and service decontamination that we have done, people are always excited to see the room or chamber filled with the yellow-green gas. The visibility confirms the fact that chlorine dioxide gas gets great distribution. It also provides a safety advantage, as the gas is recognizable inside the space, so it is visually known to be unsafe to enter.

Due to its yellow-green color, chlorine dioxide gas can be measured using a highly accurate uv-vis spectrophotometer.  The photometer shines a light through a sample of chlorine dioxide gas taken from the area being decontaminated and measures how much light was absorbed by the CD Gas.  CD Gas becomes darker in color the higher the concentration becomes, which in turn blocks more of the source light.  The photometer then converts the amount of light absorbed into a numerical value for the CD Gas concentration.  This method of concentration monitoring is highly accurate as it focuses on a specific wavelength of light, and is able to handle fluctuations in concentration rapidly compared to chemical sensors.  Measuring the concentration of gas at a single location within a space is able to accurately provide the true concentration of gas at all locations within the space. 

Learn more about the process and benefits of chlorine dioxide gas decontamination on November 13th or December 11th at our CD 101 webinar.

Friday, November 2, 2018

The Dirty Secret Of Commercial Kitchens Exposed

Guest Post written by Karoline Gore

Around 48 million illnesses and 3,000 deaths are caused every year by food contamination in the United States alone. This is quite alarming as today’s technological advancements and exposure to safe cleaning methods should drop these figures down to the bare minimum. Although sourcing meat and produce from reputable establishments is a start, one of the best places to stop the spreading of harmful bacteria is in a commercial kitchen.

Dirt Traps In Commercial Kitchens

With 50% of foodborne diseases linked to restaurants, it’s important that restaurateurs know which areas are known for causing trouble. Countertops, cutting boards and prep surfaces all need a good clean and it’s important to have designated prep areas for the different types of food. But these are obvious areas that deserve special attention. An area that doesn’t really garner that much attention is the knife block, which is said to carry as much as nine times the bacteria of a bathroom floor. Other areas worth mentioning include floor joints and grouting, loose seals on countertops, and the vegetable storage rack.

Restaurant Patrons Unknowingly Exposed

Although patrons are aware that menus are high carriers for a number of bacteria and germs, another item that reaches the table less than sanitized is a glass, particularly the rim of the glass. While crockery often gets a thorough clean with industrial equipment that uses high heat and steam to sanitize, germs get right back on the glass when staff handle the glasses for serving. Glasses are the sixth most popular place for germs to lurk and if it happens to have a slice of lemon, this figure goes up substantially. Pathogens simply move from one spot to another.

Cold Rooms And Fridges Deserve A Thorough Clean

While rotting produce and meat that’s gone beyond its use-by date are obvious targets when it comes to a good cold room cleanout, these areas require more than just a quick clean. According to The National Sanitation Foundation, there are a number of germs that lurk in these depths, making a deep clean imperative. In the vegetable department, restaurateurs can expect to find salmonella, yeast, listeria, and mold. The meat compartment may contain salmonella, E.coli, yeast, and mold.

Keeping a commercial kitchen clean is imperative for the safety of the staff and patrons. Regular hand wash and disinfectant stations, as well as a good housekeeping regime, should keep bacteria at bay.

Friday, October 26, 2018

The Fragility of Hydrogen Peroxide Vapor

In April 2018, the Medicines and Healthcare Products Regulatory Agency issued a statement regarding the sterilization of direct and indirect product contact items within isolators*.  Specifically, the organization addressed the use of hydrogen peroxide vapor (VPHP) for the sterilization of direct and indirect parts and process’ overall fragility.  The agency mentioned how VPHP can fail due to very minor occlusions, with even the fatty acids from a fingerprint are able to shield organisms from VPHP.  The position paper built on this by considering that some product contact parts (both direct and indirect) are designed in such a way that makes it difficult for hydrogen peroxide vapor to penetrate them thoroughly.  They conclude that their stance is such that hydrogen peroxide vapor cannot be used to sterilize critical items.  The MHRA then states that their expectation is that contact parts are sterilized using a robust sterilization method that meets the current requirements of Annex 1 of the EU and PIC/X GMPS for the manufacture of sterile medicinal products.  They describe a robust sterilization method as one that “reaches all of the critical surfaces in a consistent and repeatable manner.”

To read the full post,  click here.

To learn more about how chlorine dioxide gas can help accommodate this application, sign up for our upcoming webinars on Isolator Decontamination and Comparing CD Gas vs. Hydrogen Peroxide Vapor taking place over the next few weeks.

*They define indirect product contact parts as those that come into contact with items and components which do contact the product (i.e stoppers). Direct contact parts are those that the product passes through, such as pumps and filling needles.

Thursday, October 18, 2018

Decontamination Services & Applications: Life Science Industry

Chlorine dioxide (CD) gas can be utilized for a multitude of applications in the lab animal and life science industry. It is non-carcinogenic, residue-free, and safer on materials than bleach, ozone, hydrogen peroxide, and common liquid chlorine dioxide solutions. CD is not affected by environmental factors such as temperature, and is not subject to dew-point or condensation issues making it a versatile decontamination agent and allowing it to stay effective in all types of environments, including both ambient and vacuum pressure. Gaseous systems provide the ability to achieve a complete distribution and thorough penetration to each and every surface, including visible and invisible cracks and crevices. Some of the more common industry applications include animal holding rooms, BSL-3 and BSL-4 labs, biological safety cabinets, passthroughs, isolators, air handling units/ductwork, micro labs, and necropsy rooms.

Entire Facility Case Study:
ClorDiSys' chlorine dioxide gas technology allows for a complete decontamination of your facility, with minimal equipment and minimal downtime. A 170,000 ft3 new university research facility was decontaminated upon completion of construction and prior to the commencement of operations. Equipment and supplies were brought into the space as well, so that they would be exposed and decontaminated concurrently. ClorDiSys was able to fumigate the facility and eliminate any organisms present while providing sporicidal kill of Biological Indicators (comprised of 1 million Bacillus atrophaeus spores) to ensure the process was successful. The entire process took two days, one day for setup and one day for decontamination and clean-up.

BSL-3 Lab Case Study:
A BSL-3 influenza laboratory undergoes a yearly decontamination using chlorine dioxide gas during a facility shutdown. All equipment is left within the space during the process, as the gas is safe on materials and will reach all surfaces within the lab. This provided a large time savings as each piece of equipment did not need to be treated individually in an autoclave or other pass-through system. Results are shown through the placement of 40 biological indicators as various locations throughout the lab. Some locations include closed drawers, inside and behind biological safety cabinets, underneath tabletop equipment, as well as easy locations such as floors, ceilings and walls.

To learn more, attend our “Life Science and Pharmaceutical Facility Decontamination Services” webinar on Thursday, October 25th, visit Booth #1903 at the AALAS National Meeting in Baltimore, or visit our website’s Applications page.

Thursday, October 11, 2018

Eradication of Pinworm Eggs with Chlorine Dioxide

Pinworms are common contaminants of laboratory animal facilities. Pinworm infections can have adverse effects on behavior, growth, intestinal physiology, and immunology of experimental rodents, making effective pinworm surveillance and eradication important for many facilities. However, eradication of such infections is complicated by the ova’s ability to aerosolize and remain viable in the environment for lengthy periods. Pinworm eggs are microscopic and have been found on equipment, shelving, in dust, and in ventilation air intake ducts. The University of Tennessee at Knoxville performed a study on chlorine dioxide gas’ effect on pinworm eggs to see if it was a viable option for treating contaminated spaces.

Prior to this study, only ethylene oxide gas and dry heat had been proven to eliminate pinworm eggs.  Ethylene oxide is not used for space fumigation due to its carcinogenic and explosive properties, and it is very difficult to uniformly establish and maintain the high temperatures needed for dry heat (212° F held for 30 minutes) to be effective. In a controlled study, Syphacia spp. ova were affixed to a slide and exposed to a set concentration of chlorine dioxide gas for varying amounts of time. After being exposed to chlorine dioxide gas, the ova were placed in petri dishes, covered with a hatching medium, and incubated at 37° C for six hours. Positive control ova not exposed to chlorine dioxide gas were also processed and incubated.

The parameters to achieve a 6 log level kill of viruses, bacteria, fungi, and spores are normally 1 mg/L chlorine dioxide gas (360 parts per million or ppm) for 2 hours of exposure contact time.  This equates to a 720 ppm-hours (360 ppm x 2 hours) chlorine dioxide gas dosage.  It was found that a dosage twice as long (1440 ppm-hour) was needed in order to eliminate all viable ova from hatching. All ClO2 treatment times significantly decreased the hatching rates of the ova. Below is a table showing the results of the study: 

Exposure time
Chlorine DioxideGas Dosage
% of Syphacia, spp. ova hatched
Treated with CD Gas
Untreated(Positive Control)
1 hour
360 ppm-hour
2 hours
720 ppm-hour
3 hours
1080 ppm-hour
4 hours
1440 ppm-hour

To learn more about gaseous chlorine dioxide's effectiveness against pinworm eggs, visit Booth #1903 at this month's AALAS National Meeting or read the complete Journal of the American Association for Laboratory Animal Science article here.

Tuesday, October 2, 2018

Case Study: Electron Microscope Decontamination

An electron microscope can be used to study dangerous biological organisms. Occasionally, the organism can be sucked into the internals of the microscope making it hazardous to repair with concern for the maintenance technician’s health. To mitigate these concerns, decontaminating the inside components of the microscope can be accomplished using gaseous chlorine dioxide with no adverse effect on the equipment.

The normal sterilization process is automated and consists of 5 steps:
1. Precondition: Raising of humidity to make spores susceptible to gas
2. Condition: Holding of raised humidity level for spore softening
3. Charge: Injection of gas into chamber
4. Exposure: Holding of gas concentration for the set amount of time
5. Aeration: Expulsion of gas and humidity

Some microscope manufacturers add a sixth step which is a pre-purge of the system with nitrogen. If a Pre-Purge step is used, the valves are opened and nitrogen is passed through the system.

In 2009, ClorDiSys was approached by JEOL USA as they set forth to find a suitable decontamination method for their electron microscopes. They wanted a method to decontaminate the interior chambers to protect their service workers from the pathogens being studied within. Identical sets of parts were sent for material testing against chlorine dioxide and hydrogen peroxide vapor. According to “Construction and Organization of a BSL-3 Cryo-Electron Microscopy Laboratory at UTMB” in the December 2012 Journal of Structural Biology, their early attempts to use VHP with JEOL microscopes were not successful because of unacceptable level of corrosion of some parts inside the microscope column. Some showed visible discoloration and corrosion after the level of exposure necessary for a single decontamination cycle. Chlorine dioxide gas has a lower oxidation potential than ozone, peracetic acid, bleach and hydrogen peroxide, making it scientifically less corrosive than those other decontaminating agents. Our chlorine dioxide gas was selected due to its success in the material compatibility trials and is used with the $3 million TEM.

Read more about the process and benefits of using chlorine dioxide for Electron Microscope decontamination in our application note.

Tuesday, September 25, 2018

Case Study: Ductwork Decontamination

Traditional sanitation procedures typically do not include air handling units or their accompanying ductwork. Chlorine dioxide gas is the only residue free fumigation method that can successfully decontaminate ductwork and HVAC systems, including HEPA housings. Being a dry process and a true gas at room temperatures, CD is able to navigate the bends and turns of the ductwork system without condensing and getting "stuck." Typically, ductwork is decontaminated along with the rooms that it handles.  On one occasion, there was only a need to use chlorine dioxide gas to decontaminate the ductwork itself.

The exhaust ductwork in the BSL-2 and BSL-3 research laboratory of a major pharmaceutical company needed to be replaced. Since the ductwork was used to exhaust biological safety cabinets (BSCs) for testing on HIV and Hepatitis C, special precautions would be required prior to its renovation. The company decided that a fumigation style decontamination should be performed, and chlorine dioxide gas was chosen due to its ability to reach all surfaces and distribute throughout the entire length of ductwork without condensing or leaving a residue. The laboratory was located on the third floor of the building and consisted of a four-room BSL-2 area and a smaller, two-room BSL-3 area. There was a total of fourteen BSCs with exhaust ductwork that required decontamination and two ceiling exhausts. One chlorine dioxide gas generator was set up, and gas injection tubing was run to one BSC in the BSL-2 area and to one BSC in the BLS-3 area. The gas was then pulled through the exhaust system on the fifth floor and down to the distribution system and then into each BSC. A total of fifteen Bacillus atrophaeus biological indicators (BIs) were placed in each BSC and the two room exhaust vents to validate the decontamination. The results of the cycle yielded a greater than 720 ppm-hr decontamination time, which is more than adequate to provide a 6-log sporicidal reduction. All biological indicators were negative after the seven-day incubation period allowing the renovation crew to work in a safe environment without having to wear personal protective equipment (PPE).

To read this case study in its entirety, click here.

Wednesday, September 19, 2018

Follow Your Nose: CD's Best Safety Feature

While all decontaminating agents are by nature dangerous, chlorine dioxide (CD) gas has many traits which make it the safest method available. The best safety feature with CD is that it is self-alerting.  Chlorine dioxide gas has a discernible odor at safe levels, allowing you time to shut down the system and address the situation safely if it is smelled. Other agents, such as Ethylene Oxide (EtO) and Vapor Phase Hydrogen Peroxide (VPHP), cannot be sensed until you are exposed to extremely high concentrations.  This dangerous trait is why natural gas is given a sulfur-like odor additive, to act as an alert. VPHP users (and surrounding colleagues) become aware of a harmful exposure only when coughing and choking occurs, therefore a reliance on external sensors to prevent adverse health effects is more necessary.  With CD, this need for external equipment is not as strong because of its odor.  CD has an odor threshold at or below the 8-hour Time Weighted Average (TWA), so the user is self-alerted to exposure at a low level and the reliance on external sensors is not as imperative as it is with VPHP.  This makes CD safer for both the user, and any surrounding personnel who may be working nearby.

Visit our Safety page to learn more important differences between chlorine dioxide and hydrogen peroxide.

Tuesday, September 11, 2018

Is Chlorine Dioxide Carcinogenic?

A major factor in choosing a decontamination method is safety. All decontamination agents are dangerous as this is their function. However, gaseous chlorine dioxide can be used more safely than other fumigation methods due to its chemical properties and safety profile. One example of this is that chlorine dioxide gas is not a carcinogen. Formaldehyde is “known to be a human carcinogen” as described by the US National Toxicology Program. Formaldehyde was once a widely used method for decontamination, but its classification as a carcinogen has limited its use and caused it to be banned by some health agencies. The ACGIH designates vapor phase hydrogen peroxide (VPHP) as an A3, Confirmed Animal Carcinogen with Unknown Relevance to Humans. Chlorine dioxide gas is not considered to be carcinogenic, with no health organization listing CD as a carcinogen of any kind. In fact, it is used to treat fruits, vegetables, poultry, and other food products. Chlorine dioxide has also been used in the treatment of drinking water since the 1920’s both domestically and internationally.

Do you have safety concerns about the use of chlorine dioxide for decontamination? Attend our CD Gas 101 webinar on September 18th to ask questions and learn more.

Friday, September 7, 2018

Biological Safety Cabinet (BSC) Decontamination

The Class III Biological Safety Cabinet (BSC) is a gas-tight enclosure designed for work with highly infectious microbiological agents and for the conduct of hazardous operations and provides maximum protection for the environment and the worker.  A Class III BSC is typically decontaminated on a periodic basis and always before filter change out and repairs. Formaldehyde and chlorine dioxide gas are the only approved decontamination methods by NSF International. However, chlorine dioxide gas provides a much quicker cycle time than formaldehyde, is not a carcinogen, and does not leave a residue.

The Tufts New England Regional Biosafety Laboratory (RBL) is dedicated to the study of existing and emerging infectious diseases, toxin mediated diseases, and medical countermeasures important to biodefense. The facility’s two main decontamination choices are vapor-phase hydrogen peroxide (VPHP) and chlorine dioxide (CD) gas. Both agents are known to be efficacious, and both are sterilants. VPHP has been used longer, and many papers have been published on the process. Some issues of concern were that VPHP condenses and, when it does, the droplets become more aggressive or concentrated. Because of the increased concentrations, it has been documented to damage painted surfaces, epoxy surfaces, and electronics. Additionally, VPHP vapors have been shown to have limited distribution and penetration abilities. CD easily penetrates and distributes into all spaces. It covers an entire room, penetrates deeply into equipment, and gets into the hard-to-reach places. Setup is simple and requires very few extras (only 1 or 2 fans and a portable humidifier). Based on the needs to decontaminate this RBL, CD gas was the best choice as it provided complete decontamination of all surfaces within the spaces and inside the Class III BSC.

The Class III BSC can be decontaminated as part of the room (by opening the gull wing door), or it can be decontaminated on its own through use of the built-in connectors. The components needed are RH probe, mix box (which contains a humidity generator), blower motor, DC/AC controller, pressure relief scrubber, and the Minidox generator. The CD gas concentration is monitored via a gas sample port. This hose is connected to the Minidox, which then, on the basis of real-time readings, activated the gas injection system as needed. The scrubber removes any CD gas during this process. A standard cycle of 5 mg/L for 30 minutes of exposure is often used for Class III BSCs. However, due to the nature of this particular facility’s work, the cycle time was extended to 45 to 60 minutes. All biological indicators (BIs) were repeatedly killed, and no issues of corrosion were evident. All components continue to remain free of any imperfections. Due to that, chlorine dioxide gas is now the method of choice for the decontamination of Class III BSCs.

To read more about Tufts New England Regional Biosafety Laboratory’s utilization of chlorine dioxide gas for both BSC and room decontamination, click here. 

Wednesday, August 29, 2018

The Myth of Corrosion

Chlorine dioxide (CD) is an oxidizer, as is hydrogen peroxide, ozone, bleach, and many other decontaminating agents. However, CD gas is the gentlest on materials among those options, due to its lower oxidation potential. A higher oxidation potential means it is a stronger oxidizer and more corrosive. As shown in Table 1, chlorine dioxide has an oxidation potential of 0.95V, which is lower than other commonly used oxidizing biocides. CD is not as aggressive an oxidizer (oxidation potential data) as chlorine, ozone, peracetic acid, peroxide, or bleach — and it should be non-corrosive to common materials of construction.

Table 1: Oxidation Potential of Common Biocides

While scientifically less corrosive, chlorine dioxide gas has a bad reputation due to the link with chlorine as well as the other chlorine dioxide products that lack the purity that our process uses. Other methods of generating chlorine dioxide mix an acid and a base which forms a chlorine dioxide solution which is then off-gassed to fumigate a space.  That generation method produces two acidic components, acidified sodium chlorite and chlorous acid, alongside chlorine dioxide which makes these methods more corrosive. Our method of generating pure chlorine dioxide gas is accomplished by passing a low concentration chlorine gas through a proprietary sodium chlorite cartridge to convert the chlorine gas into pure chlorine dioxide gas. This allows our process to be safe when decontaminating stainless steel, galvanized metals, anodized aluminum, epoxy surfaces, electronics, and the most common materials of construction. Typically, if water will not corrode an item, neither will our CD.

To learn more about material compatibility, click here. If you have a specific item of concern, send us some samples. We offer free material testing* to give confidence that chlorine dioxide gas will be safe on your equipment, products, components, tools, etc.

*Testing is free for small items or batches. For large items or extended testing, please call (908) 236-4100. Shipping not included.

Wednesday, August 22, 2018

Decontamination Chambers

A Decontamination Chamber is designed for use in any laboratory, pharmaceutical, manufacturing, research or surgical setting. It provides a rapid and highly effective method to sterilize computers, electronics, medical devices, instruments, and components at ambient temperatures. It also provides a cost-effective method to decontaminate parts, supplies, and equipment entering a “sterile” or “clean” facility without the need for a large, expensive, energy consuming sterilizer. It allows the removal of items from a dirty or BSL level area to a clean area without the concern for cross contamination.

Chlorine dioxide gas is a highly effective EPA-registered sterilant. It is a true gas which naturally fills the space it is contained within, no matter the shape or amount of items within. CD gas has more consistent kill and quicker cycles than Vapor Phase Hydrogen Peroxide (VPHP). Decontamination time can be under 1.5 hours for a 150 ft3 chamber. The chlorine dioxide process is easy to validate due to the repeatable cycle, tight process control, and highly accurate sterilant monitoring system.  A run record is produced that contains process parameters.

For many applications, a Decontamination Chamber can effectively replace a bulk autoclave inside a facility. Decontamination Chambers can save energy and money compared to bulk autoclaves in terms of steam usage, water usage, electricity usage, maintenance costs, replacement costs, cost of capital equipment, and footprint. Chlorine dioxide gas is capable of decontaminating electronics, racks, cages, HEPA filters, plastics, and the outsides of bedding and feed bags.  Autoclaves are still the best suited to decontaminate dense organic materials such as bedding and feed. As many facilities have multiple autoclaves, the easiest decision might be to implement both an autoclave and a decon chamber to fulfill all of your facility’s needs. The equipment is available in a variety of sizes including a dual door option. We also fully integrate with BetterBuilt, Lynx, Tecniplast, Girton, Schyler, Buxton Scientific, and other manufacturers.

To learn more, visit our product page or request a decontamination chamber quote.

Wednesday, August 15, 2018

Inactivation of Beta-Lactams

Beta-lactam antibiotics are, by definition, a class of antibiotics which contain a beta-lactam ring in their structure. They are split into various groups depending upon their base structure, with the main groups being penicillins, carbapenems, cephalosporins, and monobactams. Allergic reactions to beta-lactams can be life-threatening. Due to the large number of individuals allergic, the pharmaceutical industry explored a method for their inactivation.   This research was performed such that a contaminated area could be treated and re-used for the future production of non-beta-lactam compounds. This would allow companies to “recycle” beta-lactam facilities instead of demolishing them upon the completion of production.

Testing was conducted using chlorine dioxide gas at various concentrations and exposure times in an effort to achieve the pharmaceutical manufacturer’s required 3-log (99.9%) reduction of eight different beta-lactams on various surfaces. Nine inactivation cycles were tested, with five passing the acceptance criteria beneath U.S. Food and Drug Administration (FDA)-required 0.03 ppm residue detection level. Successful inactivation cycles which achieved a 3-log reduction of all eight beta-lactam compounds all had cumulative exposures of over 7,240 ppm-hours. Further studies validated this dosage for providing a 3-log reduction of all eight beta-lactams tested.

In 2008, a leading pharmaceutical company was looking to renovate a 33-room facility, that had been used for the production of an Imipenem-based product, into a new training facility. Because positive samples for beta-lactams were found in multiple rooms and inside the ductwork, the entire production facility along with its HVAC was to be treated. Chlorine dioxide gas was injected into 24 locations and sampled from 12 locations to ensure fast and thorough distribution.  To ensure that gas was getting into the HVAC system, the recirculation blower was bumped throughout the process. Upon completion, the area was swabbed by the pharmaceutical company. All swabs came back negative proving that no beta-lactams remained, making the treatment a success.  Since that initial facility treatment in 2008, chlorine dioxide gas has been used for this specific application at a number of other facilities worldwide.

To learn more, click here.

Wednesday, August 8, 2018

How Does Chlorine Dioxide React with Water?

In most cases, before a decontamination occurs, the environment undergoes a wet cleaning to remove dirt and organic material.  This residual water can present a challenge for some decontamination methods.  One example being Vapor Phase Hydrogen Peroxide (VPHP) because it dilutes and breaks down in water.  So for that method to be effective, the area must be completely dry before use.  Depending on the application, drying the environment can be a lengthy process which adds a prohibitive amount of time to the cycle.

Chlorine dioxide (CD) gas is water soluble, allowing it to maintain its sterilization efficacy within water.  Unlike chlorine, CD gas does not form hydrochloric acid and maintains a neutral pH. In wet environments, chlorine dioxide can decontaminate any remaining water as well as the surfaces beneath.  This eliminates the need to wait until the environment is completely dry before decontamination occurs, in turn, decreasing the overall downtime.

One application where this has a real world effect is within decontamination chambers.  The use of decontamination chambers is becoming more prevalent within research facilities and clean rooms.  Within vivaria where space is extremely valuable, these chambers are sometimes included as part of a dual-use rack washer/decontamination chamber unit.  Within this application, if the system is run as a rack washer, the amount of water at the bottom of the chamber afterwards can take hours to completely dry out.  Being CD gas is not affected by water, it can be used within a dual-use chamber immediately after a wash cycle.  This can save your facility hours of time and allow the savings in facility footprint to become a viable option.  It also allows a contaminated facility the ability to become completely decontaminated as there’s no worry for residual water rendering the process ineffective.

Method Comparison: Formaldehyde

Formaldehyde has many properties which make it a highly effective sterilizing agent. The earliest reports of its use as a fumigant date back...