Sterilizing Medical Devices Using Ethylene Oxide

 

According to the Centers for Disease Control and Prevention, 48.3 million procedures were performed at hospitals and ambulatory surgery centers in the United States in 2010. Healthcare providers and patient advocates understand that infection prevention requires meticulous sanitation and sterilization of all facilities, equipment, and instruments used in surgery settings. According to the World Health Organization, post-operative infections contribute to patients’ spending extra days in the hospital, at a cost of some $900 million per year. Medical devices that are sterilized to eliminate potentially harmful pathogens and microorganisms are critical to delivering safe and cost-effective patient outcomes.

Medical Device Sterilization

Sterilization is to thoroughly clean and disinfect medical and surgical devices in order to prevent infection by killing any microorganisms (i.e., bacteria, viruses, or fungi) that might otherwise be present in the devices, and that could pose significant risks to patients.

There are a variety of sterilization methodologies in use in the healthcare industry (including, among others, steam under pressure/autoclave, dry heat, ultraviolet radiation, and gas vapors), and the most effective sterilization process in a given situation may depend on the specific type of device subject to sterilization. That is, sterilization of medical and surgical devices works best when proper techniques are used on the appropriate devices.

By way of example, high-temperature steam autoclave is the oldest sterilization technique in the medical equipment industry, and it is extremely safe, but it is not well-suited for instruments that are sensitive to prolonged exposure to heat and/or moisture. For instance, the buildup of water droplets (as a result of high-temperature steam autoclave sterilization) inside device components can corrode materials that should not be exposed to water. Likewise, instruments with plastic or electronic components could become damaged when exposed to high temperatures and steam

Sterilization Using Ethylene Oxide Gas

The use of ethylene oxide gas (EtO) has become a practical alternative to medical device sterilization via steam autoclave.

EtO was first used as a chemical sterilant in the 1950s and, since then, low-temperature EtO gas sterilization has become one of the more commonly used sterilization methods in the healthcare industry.  According to the Ethylene Oxide Sterilization Association, ethylene oxide is used to sterilize over 20 billion medical devices each year in the U.S., representing over 50% of the medical devices and nearly 90% of the surgical kits used by the healthcare industry.

EtO is a preferred sterilization method in large part because, given its low-temperature application, it will not damage medical equipment, complex implantable devices, surgical kits, and other instruments that require sterilization. Ethylene oxide has a wide range of material compatibility; it is suitable for use on materials that cannot tolerate heat, moisture, or abrasive chemicals, such as electronics, plastic, paper, and rubber, and the gas can penetrate small spaces inside the devices, and can even sterilize  medical instruments that have  already been packaged in plastic.

Protecting Employees Working in EtO Device Sterilization Environments

While ethylene oxide sterilization is widely used in sterilizing medical and surgical devices, there are concerns about the potential negative effects on employees working with EtO, since personnel and property are exposed to the possibility of leaks from gas supply lines and storage containers. Long-term exposure to ethylene oxide can irritate the eyes, skin, nose, throat, and lungs, and harm the brain and nervous system, and it has been linked to cancer.

Ethylene oxide is a highly combustible, flammable, and colorless gas that has a sweet, ether-like odor at toxic levels. However, the odor’s presence and strength cannot be relied upon to ensure safety; therefore, absent appropriate monitoring to detect that a leak or an or an accumulation of ethylene oxide has occurred, sterilization employees could face serious health risks from working in enclosed, poorly ventilated areas.

Best practices when working with EtO include, but not limited to, the use of goggles, protective clothing, and the installation of gas monitoring systems. The National Fire Protection Association (NFPA) recommends installing gas detection monitors in all areas where EtO is used. According to the NFPA, the gas monitors should provide audible and visual warnings to indicate when concentrations of ethylene oxide exceed a level of 25% of the lower limit of flammability of ethylene oxide. Furthermore, the gas detection system should automatically shut off the flow of gas and automatically turn on the buildings’ ventilation system.

PureAire Monitors

PureAire Monitoring System's ST-48 Ethylene Oxide (EtO) Combustible Gas Monitor offers continuous gas monitoring at medical sterilization facilities. The monitor is housed in a NEMA 7 explosion proof enclosure specifically designed to prevent an explosion and suitable for Class 1, Divisions 1 & 2, Groups A,B, C, and D.

PureAire’s EtO Combustible Gas Monitor features an easy to read screen, whichdisplays current gas levels for at-a-glance observation by employees, who derive peace of mind from the monitor’s presence and reliable performance. In the event that ethylene oxide reaches an unsafe level, PureAire’s monitors will set offalarms, complete with horns and flashing lights, alerting personnel to evacuate the area. At the same time, the monitors can be programmed to turn off the flow of gas, and turn on the ventilation system.

Liquid Nitrogen Dosing – Supporting Non-Carbonated Beverage Packaging, One Bottle At A Time

 

To create that perfect glass of wine, refreshing sip of water, or other non-carbonated drinks of choice, beverage producers often turn to liquid nitrogen (LN2).Liquid nitrogen fills an important role in the bottling and canning of non-carbonated beverages.

What is Liquid Nitrogen?

Liquid nitrogen is a cryogenic, liquefied form of nitrogen (N). Nitrogen is an oxygen-depleting gas that is a liquid at temperatures below −195.8° Celsius(−320.4° Fahrenheit).  At those low temperatures, liquid nitrogen is so cold that it immediately freezes. When LN2 is exposed to the air and begins to warm, it vaporizes, changing from its liquid state back to nitrogen gas.

The properties of LN2 are of particular importance to bottlers. Liquid nitrogen is an inert, odorless, and colorless gas that does not react to other substances or add unwanted flavors, odors, or colors to beverages. This ensures that products taste as they should.

Liquid Nitrogen Dosing

Liquid nitrogen dosing is a process by which, after filling the beverage container, and just before sealing it, beverage packagers dispense a precise amount of LN2 into the space (the “headspace”) between the product and the top of the bottle or can. Exposure to ambient air causes the liquid nitrogen to warm, and vaporize into nitrogen, which displaces residual oxygen and pressurizes the container.

Displacing or removing oxygen from beverage containers prevents unwanted oxidation, the presence of which can negatively impact product quality and shorten product shelf-life. Moreover, pressurizing plastic bottles and aluminum cans by introducing liquid nitrogen may improve the structural integrity of the beverage containers, and their improved durability might enable bottlers to use lighter, thinner containers, which could be both economical and environmentally friendly.

Liquid Nitrogen Safety

Liquid nitrogen usage, though important for bottling and packaging, is not without risk.

When liquid nitrogen is exposed to air (including during dosing), it evaporates, changing from a liquid to an oxygen-depleting nitrogen gas. Oxygen deprivation can put employees in real danger if there are leaks from LN2 dosing equipment or on-site gas cylinders. In the event of a liquid nitrogen leak, workers could become disoriented, lose consciousness, or even suffocate from breathing oxygen-deficient air. Since LN2 is both scentless and colorless, workers would, in the absence of appropriate monitoring, have no way of knowing that there has been a liquid nitrogen leak.

However, by utilizing a PureAire oxygen deficiency monitor, personnel can safely track oxygen levels and detect leaks before workers’ health is jeopardized. Best practice calls for oxygen deficiency monitors to be installed anywhere there is a risk of liquid nitrogen gas leaks. Monitors should be placed wherever liquid nitrogen is stored, and in all areas where liquid nitrogen is used. The monitoring equipment should include visual and audible alarms that would be activated in the event of liquid nitrogen leaks and a decrease in oxygen levels.

PureAire Oxygen Deficiency Monitors

PureAire Monitoring Systems’ complete line of Oxygen Deficiency Monitors offers thorough air monitoring, with no time-consuming maintenance or calibration required. A screen displays current oxygen levels for at-a-glance reading by employees, who derive peace of mind from the Monitor’s presence and reliable performance.

In the event of a  liquid nitrogen leak, and a decrease in oxygen to an unsafe level, PureAire’s Monitor will set off an alarm, complete with horns and flashing lights, alerting personnel to evacuate the area.

PureAire’s Monitor will remain accurate at extremely low temperatures. That makes the Monitor ideally suited for facilities using liquid nitrogen, such as bottling and packaging plants. Built with zirconium oxide sensor cells to ensure longevity, PureAire’s Oxygen Monitors can last, trouble-free, for over 10 years under normal operating conditions.

PureAire Introduces New 0-10ppm Trace Oxygen Analyzer, with Low ppb Accuracy

 

PureAire Monitoring Systems is excited to add its 0-10 parts per million(ppm) Trace Oxygen Analyzer to our full line of Oxygen Deficiency Monitors, Carbon Dioxide Monitors, Toxic Gas Detectors, and LEL Gas Monitors. The new Analyzer measures trace levels of oxygen across a wide variety of applications where precise, ultra-low gas concentration monitoring is critical to ensure safety and product quality.

Our new Trace Oxygen Analyzer provides accurate measurements of trace oxygen levels from 0-10ppm. The Analyzer’s repeatability and accuracy are <± 2% parts per billion (ppb) of the calibrated range. It is well suited for the semiconductor industry, including wafer transfer tools, process chambers, and Organic Light Emitting Diode (OLED) manufacturers, as well as 3D printing, pharmaceutical development, manufacturing, and packaging. PureAire's low ppm and ppb sensors are ideal for any applications where inert gases, including, but not limited to, nitrogen, helium, and argon are used to displace oxygen as part of the oxidation-reduction process.

PureAire’s Trace Oxygen Analyzer is designed for continuous monitoring where inert gases are used to create environments in which there is little to no oxygen present. It has a remote sensor that, with the use of a KF-type vacuum fitting, mounts directly into gloveboxes or process/vacuum chambers, and it allows for monitoring up to 10 feet away from the Analyzer.

The Near Absence of Oxygen Helps Protect Product Integrity in a Variety of Industrial Applications

The presence of oxygen in certain manufacturing processes can negatively affect the integrity of products. For instance:

• Semiconductor manufacturers seek to eliminate oxygen during key processes to protect the quality and reliability of sensitive components. The presence of trace impurities can result in the loss of whole batches of wafers.
• High-purity gas systems, laboratories, and pharmaceutical facilities require sterile, oxygen-free conditions in order to test, manufacture, package, and deliver pure, contaminant-free gases, drugs, and medicines.
• Food packagers and bottlers know that residual oxygen can promote the growth of microorganisms such as mold and other pathogens, potentially leading to foul tastes, off-textures, and shortened shelf-life of food and beverage products and, in certain instances, food-borne illnesses.

PureAire Trace Oxygen Analyzer

PureAire’s Trace Oxygen Analyzer should be used in any location where precise measurements of oxygen levels need to be maintained, and where the presence of oxygen could negatively affect product integrity.

Our Analyzer responds in seconds to changes in oxygen levels, and in the event of an unacceptable deviation in required O2 levels, will set off an alarm, complete with horns and flashing lights, alerting personnel to take corrective action.

PureAire’s durable, non-depleting, long-life zirconium oxide sensor will remain accurate over a wide range of temperature and humidity levels, and it will last for 10+ years in a normal environment without needing to be replaced.

PureAire Introduces New 0-100 ppm Trace Oxygen Analyzer

 

PureAire Monitoring Systems is excited to add its 0-100 parts per million(ppm) Trace Oxygen Analyzer to our full line of Oxygen Deficiency Monitors, Carbon Dioxide Monitors, and Combustible/Toxic Gas Detectors. The new Analyzer measures trace levels of oxygen across a wide variety of applications that require real-time, ultra-low gas concentration monitoring to ensure safety and product quality.

PureAire’s Trace Oxygen Analyzer is designed for continuous monitoring where inert gases are used to create environmentsin which there is little to no oxygen present. It has a remote sensor that, with the use of a KF type vacuum fitting, mounts directly into gloveboxesor process/vacuum chambers, and it allows for monitoring up to 10 feet away from the Analyzer.

Our new Trace Oxygen Analyzer is capable of measuring oxygen levels from 0-100 ppm. It is well suited for the semiconductor industry, including wafer transfer systems, process chambers, and Organic Light Emitting Diode (OLED) manufacturers, as well as 3D printing, welding, pharmaceutical development, manufacturing, and packaging, and for any applications where inert gases, including, but not limited to, nitrogen, helium, and argon are used to displace oxygen.

The Near Absence of Oxygen Helps Protect Product Integrity in a Variety of Industrial Applications

The presence of oxygen in certain manufacturing processes can negatively affect the integrity of products. For instance:

• Semiconductor manufacturers seek to eliminate oxygen during key processes to protect the quality and reliability of sensitive components.
• High-purity gas systems, laboratories, and pharmaceutical facilities require sterile, oxygen-free conditions in order to test, manufacture, package, and deliver pure, contaminant-free gases, drugs, and medicines.
• Food packagers and bottlers know that residual oxygen can promote the growth of microorganisms such as mold and other pathogens, potentially leading to foul tastes, off-textures, and shortened shelf-life of food and beverage products and, in certain instances, food-borne illnesses.

PureAire Trace Oxygen Analyzer

PureAire’s Trace Oxygen Analyzer should be used in any location where precise measurements of oxygen levels need to be maintained, and where the presence of oxygen could negatively affect product integrity.

Our Analyzer responds in seconds to changes in oxygen levels, and in the event of an unacceptable deviation in required O2levels,will set off an alarm, complete with horns and flashing lights, alerting personnel to take corrective action.

PureAire’s durable, non-depleting, long-life zirconium oxide sensor will remain accurate over a wide range of temperature and humidity levels, and it will last for 10+ years in a normal environment without needing to be replaced.

PureAire Introduces New Dual Oxygen/Carbon Dioxide Monitor

 PureAire Monitoring Systems is excited to introduce its new Dual Oxygen/Carbon Dioxide Monitor, an important addition to our full line of Oxygen Deficiency Monitors, Carbon Dioxide Monitors, and Combustible/Toxic Gas Detectors.  Our new Monitor is designed for continuous monitoring of oxygen and carbon dioxide levels  across a wide variety of applications, including cryogenic facilities, breweries, food processing plants, cannabis grow rooms, pharmaceutical manufacturing operations, laboratories, hospitals, and universities.

Our Dual Monitor can sample O₂/CO₂ levels from up to 100 feet away and is ideal for facilities that use inert gases, including, but not limited to, nitrogen, helium, and argon. Its NEMA 4X/IP66 dust-tight and water-tight enclosure will protect the Monitor against dust, water, and damage from ice formation.

PureAire’s new Dual O₂/CO₂ Monitor continually measures oxygen levels from 0-25%, and carbon dioxide levels from 0-50,000 parts per million (ppm), with both O₂ and CO₂ measurements readily visible on the Monitor’s easy-to-read backlit displays. Depending on our customers’ specific requirements, the Monitor can be linked to a programmable logic controller (PLC), a multi-channel controller, or tied into building systems themselves.

The new O₂/CO₂ Monitor features dual built-in LED visual alarms, two alarm level set-points for both O₂ and CO₂, as well as two relays for each monitored gas. The Monitor responds in seconds to changes in oxygen and carbon dioxide levels, and it will remain accurate over a wide range of temperature and humidity levels.

PureAire’s Dual Oxygen/Carbon Dioxide Monitor offers thorough air monitoring, with no time-consuming maintenance or calibration required. Built with durable, non-depleting, zirconium oxide sensor cells, and non-dispersive, infrared (NDIR) sensor cells to ensure longevity, PureAire’s Dual O₂/CO₂ Monitor can last, trouble-free, for 10+ years in normal working conditions.

Thermal Vacuum Chambers: A Must Have for Space Exploration

 

On October 4, 1957, the Soviet Union launched the first artificial satellite into space, thus ushering in the Space Age. Since then, over 8,000 satellites have been launchedfrom more than 50 countries. According to Jonathan McDowell, an astronomer at the Harvard-Smithsonian Center for Astrophysics, at the end of 2021 there were around 5,000 active satellites in orbit.

In addition to all of those satellites, space is currently home to a number of other pieces of equipment, including two space stations, the Hubbell and James WebbSpace Telescopes,as well as robotic equipment, including six motorized robotic vehicles(or rovers) currently on Mars.

Once launched, equipment is expensive to replace and difficult to repair if it gets lost or damaged.  In order to ensure reliability, safety, and that satellites, spacecraft, and related components will operate as intended, nearly all equipment destined for the final frontierundergo intensive testing, prior to launch, in environmentsthat replicate the conditions actually found in space.

Space is a harsh environment, and every component will be subjected to conditions unlike anything found on Earth,including microgravity, extreme hot and cold temperature cycling, ultra-vacuum atmosphere, and high-energy radiation.

Thermal Vacuum Chambers

One key aspect of the testing includes the use of thermal vacuum chambers (TVC) to replicate the ultra-cold temperatures and the airless vacuum of space.  The extreme cold and absence of air pressure in TVCs will help identify flaws or weaknesses in the equipment tested.

Thermal vacuum chambershave been used for a number of years by the aerospace industry. In fact, Thermal Vacuum Chamber A, located at NASA’s Johnson Space Center in Houston, was used to test both the Apollo spacecraft before their historic missionsto space and, following upgrades, the James Webb Telescope prior to its launch in 2021.

Once equipment to be tested is placed inside the TVC, the air is evacuated. When the air, and accompanyingair pressure,areremoved, gas trapped in materials is released, and outgassing begins to occur. The released gases, and other impuritiesinside the chamber, will begin to evaporate and may condenseon the equipment,potentially making it less accurate or even unusable.

To reduce the temperature inside the chamber, and to remove lingering gases and impurities from the chamber, TVCs typically utilize cryopumps. These pumps, located at the bottom of the chambersuse cryogenic gases, such as liquid nitrogen (LN₂) or helium (He), to super-chill the air and the surfaces of the cryopump tobetween -208 Celsius and -261 Celsius.  As the air in the chamber passes over the surfaces, gases such as oxygen, nitrogen, helium, and hydrogen instantly freeze to the surfaces of the cryopump and are, effectively, removed from the chamber.

Oxygen Deprivation Risks When Using Cryogenic Gases

Clearly, liquid nitrogen and helium play a vital role in the development and testing of equipment used in space exploration. However, there are risks associated with use of LN₂ and He. Liquid nitrogen and helium are oxygen-depleting gases that are both odorless and colorless. As such, absent appropriate gas monitoring equipment, personnel working near thermal vacuum chambers would likely be unable to detect LN₂ or He leaks, and an accompanying decrease in oxygen.

According to the Occupational Safety and Health Administration (OSHA), an environment in which oxygen levels fall below 19.5 percent is considered an oxygen-deficient atmosphere and should be treated as immediately dangerous to health or life. When there is not enough oxygen in the air, persons working in the affected area may become disoriented, lose consciousness, or even suffocate due to the lack of sufficient oxygen.

PureAire Oxygen Monitors

PureAire Monitoring Systems’ Oxygen Deficiency Monitor offers thorough air monitoring, with no time-consuming maintenance or calibration required. Best practice calls for oxygen monitors to be installed anywhere there is a risk of gas leaks—i.e., wherever cryogenic gases, including liquid nitrogenand helium, are stored, and in all locations where these gases are used.

A screen displays current oxygen levels, for at-a-glance reading by employees, who derive peace of mind from the Monitor’s presence and reliable performance.

Built with zirconium oxide sensor cells, to ensure longevity, the Monitor can last, trouble-free, for 10+ years in normal working conditions.

In the event of a liquid nitrogen or helium gas leak,where oxygen decreases to unsafe levels, PureAire’s Monitor will set off an alarm, complete with horns and flashing lights, alerting personnel to take corrective action.

For over 20 years, PureAire Monitoring Systems has been an industry leader in manufacturing long-lasting, accurate, and reliable Oxygen Deficiency Monitors. We have dedicated ourselves to ensuring the safety and satisfaction of our clients, many of which have very sophisticated operating requirements. We are proud to note that NASA’s SOFIA-Stratospheric Observatory for Infrared Astronomy–a Boeing 747SP aircraft modified to carry a 2.7 meter (106 inch) reflecting telescope–carries onboard a PureAire Oxygen Deficiency Monitor.

Monitoring Off-Gasses to Guard Against Thermal Runaway Risk with Li-Ion Batteries

 

Lithium-Ion Batteries

Rechargeable lithium-ion (“li-ion”) batteries (comprised of cells in which lithium ions move from a negative electrode through an electrolyte to a positive electrode during discharge—and the other way around when charging) were first described conceptually in the 1970s.

Following initial prototype development in the 1980s, li-ion batteries became commercially viable in subsequent decades, and they are now commonly used in a variety of portable consumer electronic devices, including cell phones, laptops, and tablets.

Li-ion batteries also provide power for a broad array of automotive, aerospace, and commercial energy applications, such as electric vehicles (i.e., cars, trucks, buses, and trains), drones and satellites, and battery energy storage systems (or “BESS”, which enable power system operators and utilities to store energy—including that generated from renewable power sources—for later discharge and distribution as demand necessitates).

Analysts expect that the global size of the lithium-ion battery market will grow from some $40 billion in 2021 to over $115 billion by 2030, as users increasingly appreciate li-ion batteries for their rechargeability, large storage capacity, slow loss of charge when not in use, and high power to weight ratio.

However, those involved with li-ion battery production and usage must live with the inherent safety hazards involved with these batteries, as their electrolytes are flammable by nature, which can, at high temperatures, lead to fires and explosions.

Thermal Runaway Can Impact Lithium-ion Battery Safety

In 2019, a battery failure at an Arizona BESS facility operated by the Arizona Public Service (“APS”) utility resulted in an explosion that caused serious injuries to a number of firefighters. The APS site housed over 10,000 lithium-ion battery cells in 27 battery racks within a relatively small battery storage enclosure.

Authorities believe that the explosion, which they attributed to a chain reaction process knows as “thermal runaway”, was initiated by a failure in just one li-ion battery cell, which leaked explosive gas which, in turn, combusted as soon as the firefighters, responding to an alarm and reports of gas clouds emanating from the structure, opened the door and let oxygen into the storage enclosure.

Described simply, thermal runaway is an exothermic reaction in which li-ion battery cell temperatures rise rapidly in an uncontrollable self-exacerbating fashion. As cell temperatures rise, flammable and/or toxic gasses are vented (that is, “off-gassed”) from the battery.

While the gasses may not ignite immediately, the risk for a potential gas explosion remains. Ultimately, pressure from the buildup of gas can cause the cell to rupture and release toxic or explosive gasses (most commonly, carbon dioxide, carbon monoxide, fluorine, hydrogen, and methane, though there may be others).

An after-incident report commissioned by APS and released in 2020 listed a number of incidents from 2006-2017 involving thermal runaway events in lithium-ion batteries, including one on a tugboat in 2012 and another on a Boeing 787 in 2013.

There have been other such events as well including, memorably, a 2017 fire and explosion in Houston, TX on a train car that was transporting lithium-ion batteries to a recycling facility. The explosion broke windows in nearby buildings and, reportedly, sent a chemical stench throughout downtown Houston.

Off-Gas Monitoring Can Reduce the Risk of Thermal Runaway

Lithium-ion battery off-gassing, and subsequent thermal runaway, can occur due to manufacturing defects, mechanical damage or failures, overvoltage, excessive heat, or improper handling or storage.

Unfortunately, without reliable gas detectors in place, there is no sure way to know, until it is too late (i.e., when thermal runaway has actually started), that battery cells have in fact begun to off-gas.

To detect off-gasses, and protect against thermal runaway, best practices call for manufacturers, researchers, facility operators, storers, transporters, and others working with li-ion batteries to install high-quality gas detection monitors.

The gas detectors should continuously monitor all relevant areas and, if off-gas concentrations are detected, activate alarms and turn on ventilation systems.

PureAire Monitoring Systems

PureAire Monitoring Systems’ ST-48 Gas Detector tracks levels of toxic and/or combustible off-gasses including, but not limited to, carbon dioxide, carbon monoxide, fluorine, hydrogen, and methane. 

The ST-48 is housed in a NEMA 7 explosion-proof enclosure suitable for Class 1, Divisions 1 and 2, Groups A, B, C, and D, making it ideal for locations (including li-ion storage facilities and electric vehicle manufacturing plants) where toxic and/or combustible gasses may accumulate.

PureAire’s ST-48 Gas Detector offers continuous readings of toxic and/or combustible gasses and features an easy-to-read screen, which displays current gas levels, in either parts per million (ppm) or lower explosive limit (LEL), for at-a-glance observation.

In the event of an accumulation of off-gasses to an unsafe level, the Detector will set off an alarm, complete with horns and flashing lights, alerting personnel to evacuate the area and contact appropriate first responders.

Importantly, the PureAire Gas Detector can be programmed to tie into ventilation systems when off-gas levels reach a user-selectable ppm or LEL, so that the gasses can be flushed before human life is jeopardized.