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Work Practice Guidelines For Ethylene Oxide Sterilizers

  DANGER! ETHYLENE OXIDE: CANCER AND REPRODUCTIVE HAZARD Ensure that the sterilizer ventilation system is operational before starting and during operation. Use in-chamber aeration whenever possible. When transferring a sterilizer load to an aerator, follow these precautions: After completing the required purge/aeration cycles, leave the load in the sterilizer for additional cycles as time permits. Verify the functionality of local exhaust ventilation above the sterilizer door. Open the sterilizer door to the notched position 𝑜𝑟2𝑖𝑛𝑐ℎ𝑒𝑠𝑖𝑓𝑛𝑜𝑛𝑜𝑡𝑐ℎ𝑒𝑑𝑝𝑜𝑠𝑖𝑡𝑖𝑜𝑛𝑖𝑠𝑎𝑣𝑎𝑖𝑙𝑎𝑏𝑙𝑒or2inchesifnonotchedpositionisavailable and vacate the area for 15 minutes. Transfer the load swiftly and maintain a distance from the face. In the event of an ethylene oxide leak or emergency, evacuate the area immediately and implement the emergency response plan. DO NOT RE-ENTER WITHOUT A SUPPLIED-AIR RESPIRATOR. Work Practice Guidelines for Ethylene Oxide Sterilizers: Posted Near Ethylene Oxide Supply Cylinders Before replacing cylinders, ensure local exhaust ventilation for the cylinder is operational. When changing cylinders, wear a full faceshield, protective gloves, and other required protective clothing as per OSHA 29𝐶𝐹𝑅1910.104729CFR1910.1047 regulations. Prior to disconnecting the supply line from the cylinder valve, release excess pressure by venting the supply line into the ventilation system. In the event of an ethylene oxide leak or emergency, evacuate the area immediately and follow the emergency response plan. DO NOT RE-ENTER WITHOUT A SUPPLIED-AIR RESPIRATOR. Work Practice Guidelines for Ethylene Oxide Sterilizers: Posted at Mechanical Access Room Entrances CAUTION! This room may contain high concentrations of ethylene oxide. In the event of an ethylene oxide leak or emergency, evacuate the area immediately and initiate the emergency response plan. DO NOT RE-ENTER WITHOUT A SUPPLIED-AIR RESPIRATOR.

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Storage, Handling, And Use Of Ethylene Oxide For Sterilization And Fumigation

California Compressed Gases and Cryogenic Fluids Code -Storage, Handling, and Use of Ethylene Oxide for Sterilization and Fumigation 14.1 GeneralThe storage, handling, and use of ethylene oxide for sterilization and fumigation shall be in accordance with the provisions of Chapters 1 through 7, as applicable. 14.2 Receiving and Unloading Ethylene Oxide Containers 14.2.1 ScopeThis subsection shall apply to the handling of both full and empty ethylene oxide containers at a facility, including the following:Handling of the containers between the truck and the dockInspecting containers at the dockHandling of the containers within the facility 14.2.2 Procedures 14.2.2.1Drums shall not be lifted by placing the forks under the chime rings on the drums. 14.2.2.2Prior to the unloading of ethylene oxide containers, the vehicle engine shall be turned off, the brakes set, and the wheels chocked. 14.2.2.3Smoking or open flames shall not be permitted within 25 ft (7.62 m) of any area where ethylene oxide containers are handled. 14.2.2.4Ethylene oxide cylinders shall be secured to hand trucks or lift trucks during movement. 14.2.2.5Ethylene oxide containers shall be kept upright at all times. 14.2.2.5.1Containers shall not be stacked or rolled. 14.2.2.6Immediately after offloading, ethylene oxide containers shall be inspected and the following checks performed:An examination for evidence of damage to the container or valvesA confirmation that the valves are equipped with valve outlet plugs or capsAn inspection of the container labeling to confirm that each container is labeled as containing ethylene oxide* A leak test of the container, including valves and fuse plugs 14.2.2.6.1Ethylene oxide containers shall not be moved to storage until the inspection is complete. 14.2.2.7In the event that any container fails incoming inspection, the ethylene oxide supplier shall be notified. 14.2.2.7.1If a leaking container is found, the facility procedures for handling ethylene oxide leaks and spills shall be followed. 14.3 Storage of Ethylene Oxide 14.3.1 General 14.3.1.1Ethylene oxide containers shall be kept upright at all times. 14.3.1.2Ethylene oxide containers shall not be stacked. 14.3.2 Indoor Storage 14.3.2.1 Storage Within Sterilization Buildings 14.3.2.1.1*The maximum quantity of ethylene oxide stored in a sterilization building shall be 10,000 lb (4536 kg). 14.3.2.1.2The construction of all such sterilization buildings shall comply with Section 14.11. 14.3.2.1.3Rooms within sterilization buildings shall be classified for purposes of ignition source control in accordance with 14.7.1.1. 14.3.2.1.4Heated indoor storage areas shall be arranged so that stored cylinders or other containers cannot be spot heated or heated above 125°F (51.7°C). 14.3.3 Storage Outside of Buildings 14.3.3.1 Location of Storage Outside of BuildingsStorage outside of buildings shall be located in accordance with 7.10.2 and 7.10.3. 14.3.3.2 Outdoor Storage Areas 14.3.3.2.1Outdoor storage areas shall have a minimum of 25 percent of the perimeter open to the atmosphere. 14.3.3.2.2This open space shall be permitted to incorporate chain link fence, lattice construction, open block, or similar materials for the full height and width of the opening. 14.3.3.2.3Storage areas shall be kept clear of dry vegetation and combustible materials for a minimum distance of 15 ft (4.6 m). 14.3.3.2.4Cylinders stored outside shall not be placed on the ground (earth) or on surfaces where water can accumulate. 14.3.3.2.5Storage areas shall be provided with physical protection from vehicle damage. 14.3.3.2.6*Storage areas shall be permitted to be covered with canopies of noncombustible construction. 14.4 Piping Systems 14.4.1 Scope 14.4.1.1This section shall apply to ethylene oxide piping systems, including pipe, tubing, flanges, gaskets, valves, fittings, flexible connectors, and to the pressure-containing parts of other components, such as expansion joints and strainers, and devices used to mix, separate, distribute, meter, and control the flow of ethylene oxide. 14.4.1.2This section shall not apply to scrubber and vent systems. 14.4.1.3 Cleaning and Purging of Gas Piping SystemsCleaning and purging of piping systems shall be in accordance with 7.1.18. 14.4.2 Materials for Piping, Valves, and Fittings 14.4.2.1 Materials 14.4.2.1.1All metallic materials used shall be as specified in ASME B31.3, Process Piping. 14.4.2.1.2The requirements of the hazardous materials section shall apply. 14.4.2.1.3The following restrictions shall also apply:All metallic materials used shall have a minimum melting point greater than 1500°F (815.6°C).No furnace butt-welded steel product shall be used. 14.4.2.2* Joining Methods 14.4.2.2.1Joints shall be made gastight and shall be welded, flanged, brazed, or threaded. 14.4.2.2.2Joints shall be welded where located in concealed spaces within buildings. 14.4.2.2.3The requirements in 14.4.2.2.3.1 through 14.4.2.2.3.4 shall apply. 14.4.2.2.3.1 Welding (A)All welding processes and procedures shall be in conformance with ASME B31.3, Process Piping. (B)The Oxy-Fuel Gas Welding (OFW) procedure shall not be used on any component or system fabricated to this code. 14.4.2.2.3.2 Brazing (A)All brazing processes and procedures shall be in strict conformance with ASME B31.3, Process Piping. (B)All braze alloys shall have a minimum melting point of 1000°F (537.8°C). (C)The failure of the braze joint in the event of a fire exposure shall not in any way result in the release of additional fuel that can accelerate or spread the existing fire. 14.4.2.2.3.3 Soldering (A)Soldering shall not be used for pressure containment or structural purposes. (B)Soldering for hermetic or environmental sealing purposes as part of a mechanical sealing system shall be permitted. (C)The failure of any soldering application in the event of a fire shall not allow a release of fuel that can accelerate or spread the existing fire. 14.4.2.2.3.4 ThreadingThreaded joints shall be made with a thread sealant or lubricant compatible with ethylene oxide. 14.4.3* Preparation for Dismantling of Piping 14.4.3.1Piping and valves that have been used to transport ethylene oxide to or from a sterilizer to the emission control or release point shall be drained and purged in accordance with 7.1.18 prior to dismantling. 14.4.3.2The piping shall be purged free of flammable concentrations of ethylene oxide prior to cutting or welding on the lines. 14.4.3.3The piping shall be inspected for evidence of polymers prior to cutting or welding. 14.4.3.4If found, all polymers shall be removed prior to cutting or welding. 14.4.4 Valves 14.4.4.1Valves shall be designed for a minimum operating gauge pressure of 150 psi (1030 kPa). 14.4.4.2All materials used, including valve seat discs, packing, seals, and diaphragms, shall be in accordance with 14.4.2. 14.4.5 TestingPressure piping systems shall be tested in accordance with ASME B31.3, Process Piping, prior to use. 14.4.6* IdentificationEthylene oxide lines shall be identified. 14.5 Gas Dispensing Areas 14.5.1 GeneralIn addition to the requirements in Section 14.3, the requirements in 14.5.1.1 through 14.5.1.3 shall apply to areas where ethylene oxide is dispensed from containers. 14.5.1.1Ethylene oxide storage shall be permitted in dispensing areas. 14.5.1.2*Indoor dispensing areas shall be equipped with a continuous gas detection system that provides an alarm when ethylene oxide levels exceed 25 percent of the LFL (7500 ppm). 14.5.1.3*Exhaust ventilation shall be installed in all indoor dispensing areas used for ethylene oxide. 14.5.1.4Exhaust ventilation shall comply with the following:Mechanical ventilation shall be operated continuously at a rate of not less than 1 scf/min•ft2 (0.3 Nm3/min•m2) of floor area of dispensing area.Exhaust ventilation shall not be recirculated within a room or building unless under the following conditions:Where the air is treated to reduce the ethylene oxide concentration to below that which represents a hazard, recirculation shall be permitted.Controls shall be provided to ensure the performance of the treatment and recirculation system.The ventilation system shall be designed to prevent accumulation of ethylene oxide anywhere in the dispensing area. 14.5.2 Ethylene Oxide Containers 14.5.2.1No more than two ethylene oxide containers shall be connected to each sterilizer. 14.5.2.2Before connections are made, containers shall be grounded. 14.5.2.3The ethylene oxide supply line shall have a reverse flow prevention device to prevent contamination of the supply container where automatic switchover of containers is used. 14.5.2.4Each ethylene oxide piping system from the containers to the process chamber shall have two remotely operated shutoff valves in the flow stream. 14.5.2.4.1The valve required in 14.5.2.4 closest to the container shall be located 5 ft (1.5 m) or less from the container. 14.5.2.4.2The valves shall be operable from the sterilizer control room or other location outside the dispensing area. 14.5.2.5Any supply piping containing liquid ethylene oxide that can be isolated shall be equipped with a pressure relief device. 14.5.3 Nitrogen System 14.5.3.1Nitrogen used for head space pressurization shall be no less than 99.0 percent nitrogen and shall contain no impurities that are chemically incompatible with ethylene oxide. 14.5.3.2A reverse flow prevention device shall be provided to prevent ethylene oxide from entering the nitrogen supply system. 14.5.3.3A particulate filter shall be provided to prevent rust from being introduced into an ethylene oxide container. 14.5.3.4Refillable containers shall be pressurized with nitrogen to a gauge pressure of 50 psi (345 kPa) prior to disconnection and shipment to the supplier. 14.5.4 Vaporizer 14.5.4.1 Liquid Flow Control Valve 14.5.4.1.1A valve shall be provided to control liquid flow to the vaporizer. 14.5.4.1.2This valve shall be permitted to be one of the valves required in 14.5.2.4. 14.5.4.2* Temperature Recording Device 14.5.4.2.1An indicating or recording device shall be provided at the control panel to demonstrate that the ethylene oxide temperature is within the range of 60°F (16°C) to 200°F (93.3°C). 14.5.4.2.2An alarm shall be provided for out-of-range conditions. 14.5.5 Liquid Ethylene Oxide PipingEthylene oxide shall not be piped outside the confines of the process area. 14.6 Operations 14.6.1 Operating Procedures Manual 14.6.1.1Each facility shall prepare and maintain an operating procedures manual covering facility start-up, operation, and shutdown. 14.6.1.2Operating procedures manuals shall include procedures for the safe operation of the facility under normal and nonroutine operation conditions. 14.6.1.3Operating procedures manuals shall be accessible to facility operators at all times. 14.6.1.4Operating procedures manuals shall include operator actions to be taken if toxic or flammable concentrations of ethylene oxide are detected in the facility. 14.6.1.5Operating procedures manuals shall include procedures for purging and inerting equipment and piping. 14.6.1.6Operating procedures manuals shall include procedures for addressing leakage and spills of ethylene oxide. 14.6.2* Sterilizer Operation 14.6.2.1* PurgingThe vessel shall be purged to reduce the ethylene oxide concentration to less than 25 percent of the LFL prior to opening the chamber door. 14.6.2.2* Postcycle VentilationA nonrecirculating ventilation system or equivalent means shall be provided to prevent ethylene oxide accumulation due to product outgassing prior to and during unloading of the sterilizer. 14.6.2.3 Cycle Abort 14.6.2.3.1Ethylene oxide sterilizers shall be equipped with a manually initiated cycle abort feature accessible to the operator. 14.6.2.3.2This cycle abort feature also shall be operable from outside the sterilizer area. 14.6.2.3.3A key-locked device shall not be permitted. 14.6.2.3.4The cycle abort operation shall allow for the controlled removal of flammable concentrations of ethylene oxide from the sterilizer. 14.6.3 Area Monitoring for Ethylene OxideEthylene oxide sterilizer areas shall be monitored continuously for ethylene oxide concentrations. 14.6.3.1The gas detection system shall provide an audible and visual warning signal to indicate when concentrations of ethylene oxide reach a level of 25 percent of the LFL of ethylene oxide. 14.6.3.2*The gas detection system shall automatically shut off the supply at the ethylene oxide containers when the concentration of ethylene oxide exceeds 25 percent of the lower limit of flammability. 14.6.4 Emergency Stop 14.6.4.1An emergency stop device shall be provided to halt all operating equipment, including valves, rotating equipment, and heating apparatus on the sterilizer and gas dispensing equipment. 14.6.4.2The emergency stop shall be activated by a manually initiated feature accessible in the control room or at the control panel. 14.7 Electrical Installation 14.7.1 Area Electrical Classification 14.7.1.1The sterilizer room, gas dispensing room, ethylene oxide container storage area, aeration rooms, and emission control area shall be classified as a Class I, Division 2, Group B area in accordance with NFPA 70, unless under the conditions of 14.7.1.1.1. 14.7.1.1.1Aeration rooms shall be permitted to be unclassified electrically where it is demonstrated that flammable concentrations of ethylene oxide cannot occur during all normal and nonroutine operating conditions, including power failure. 14.7.1.2The interior of the sterilization vessel shall be classified Class I, Division 1, Group B. 14.7.2* Static Electricity ControlAll piping shall be bonded to an earth ground. 14.7.3 Grounding RequirementsAll equipment shall be grounded in accordance with NFPA 70, Article 250. 14.8 Sterilizer Construction 14.8.1* VesselSterilizers operating at gauge pressure of 15 psi (100 kPa) or higher shall be designed, built, and stamped in accordance with the ASME Boiler and Pressure Vessel Code, Section VIII. 14.8.2 Rotating EquipmentRotating equipment exposed to flammable concentrations of ethylene oxide shall be designed to prevent sparking and localized overheating of surfaces during normal and nonroutine operation. 14.8.3 Pressure Relief DeviceA pressure relief device, set to open at the sterilizer's design pressure, shall be installed on each sterilizer. 14.8.3.1Pressure relief devices shall be inspected annually for corrosion or accumulation of material (such as polymer buildup) that could prevent operation. 14.8.3.2The point of discharge of the pressure relief device shall not be located in an area where potential ignition sources exist or where ethylene oxide vapors could re-enter the building. 14.8.3.3Shutoff valves shall not be installed in relief device discharge piping. 14.9 Disposal and Emissions 14.9.1* ScopeThis section shall apply to the disposal and emission of ethylene oxide from sterilization buildings. 14.9.2 Wet ScrubbersWhere a wet scrubber is used, the following requirements shall apply:Wet scrubbing systems shall be designed so that scrubber solution cannot enter ethylene oxide vent or process lines.Sources of pure ethylene oxide liquid shall be prevented from being fed directly to scrubber systems designed only for ethylene oxide gas treatment. 14.9.3 Flare StacksWhere a flare stack is used, the following requirements shall apply:Flame arresters shall be installed to prevent flame flashback into the sterilizer.Flare stack failure shall initiate a shutdown of the flare stack feed and an audible alarm. 14.9.4 Catalytic ConverterWhere a catalytic converter is used, it shall be designed to shut down or be bypassed if the temperature exceeds the maximum temperature determined by the catalyst supplier. 14.9.5* Oxidizing Emission Control Devices 14.9.5.1 General 14.9.5.1.1All interlocks and safeguards shall be in place before sterilization begins. 14.9.5.1.2Sterilization products that sit idle in the sterilization or aeration room shall be periodically washed or vented. 14.9.5.1.3Confined spaces shall be vented to the outside after power loss. 14.9.5.1.4Regular preventive maintenance shall be performed. 14.9.5.2 Sterilizers Equipped With Back-Vent Systems Connected to Emission Control Devices 14.9.5.2.1Sterilizers equipped with a back-vent system connected to an oxidizing emission control device shall be in accordance with 14.9.5.2.1. 14.9.5.2.1.1*Engineering controls shall be provided to ensure that residual ethylene oxide concentration at the entrance to the oxidizing emission control device does not exceed 25 percent of the LFL (0.75 percent by volume). (A)The sterilization chamber shall be equipped with gas detection to monitor the concentration of ethylene oxide within the sterilization chamber. (B)A safety interlock shall be provided to prevent the backvent system from opening if the concentration of ethylene oxide in the sterilization chamber exceeds the predetermined limits required by the operating procedures specified in 14.6.1.1. (C)*Exhaust duct systems used to convey ethylene oxide vapors shall be in accordance with the mechanical code. 14.9.5.3Piping used to convey ethylene oxide to the sterilization process shall not be purged to an oxidizing emission control device. 14.10 Maintenance 14.10.1 General RequirementsA written program shall be developed for the following maintenance activities:Confined space entryPurging of equipment and pipingWelding (hot work) permit systemLockout/tagoutPreventive maintenance for key equipment 14.10.2 Maintenance ManualsManuals shall be accessible to facility operators and maintenance personnel at all times. 14.11 Construction 14.11.1 Scope 14.11.1.1This section covers the construction, ventilation, and heating of structures that house ethylene oxide storage, dispensing, and use. 14.11.1.2These structures shall be used exclusively for ethylene oxide storage, dispensing, and use and for the housing of other materials having similar hazards, or they shall be permitted to be rooms attached to or located within buildings used for other purposes. 14.11.2 Separate Structures or Buildings 14.11.2.1 Construction of Structures or BuildingsSeparate structures or buildings shall be one story in height and shall have walls, floors, ceilings, and roofs constructed of noncombustible or limited-combustible materials. 14.11.2.1.1Exterior walls, ceilings, and roofs shall be constructed in one of the following ways:Of lightweight material designed for explosion venting* Of heavy construction, such as solid brick masonry, concrete block, or reinforced concrete construction, provided there are explosion venting windows or panels in the walls or roofs 14.11.2.1.2The floor of such structures or buildings shall not be located below ground level. 14.11.2.1.3Any space beneath the floor shall be of solid fill, or the perimeter of the space shall be entirely unenclosed. 14.11.2.2* Structure or Building VentilationThe structure or building shall be provided with general ventilation through the use of air supply inlets and exhaust outlets. 14.11.2.2.1These inlets and outlets shall be arranged to provide movement of well-mixed air throughout the space. 14.11.2.2.2Air circulation shall be at least 1 scf/ft2 (0.3 Nm3/m2) of floor area and shall be permitted to be provided by natural or mechanical means. 14.11.2.3 Structure or Building HeatingHeating shall be by electrical appliances listed for Class I, Group B, Division 2 locations in accordance with NFPA 70 or shall be by means of steam or hot water radiation or other heating transfer medium with the heat source located in one of the following locations:Outside the buildingIn a separate room with a 2-hour fire resistance rating pressurized relative to the remainder of the building 14.11.2.4 Sterilization RoomsThe sterilization room shall be provided with Protection Level 2 and Protection Level 4 controls as specified by the building code. 14.11.2.4.1Sterilizing rooms with quantities of hazardous materials, including ethylene oxide, in quantities less than the MAQ per control area as established by the building code shall not be required to have Protection Level 2 and Protection Level 4 controls. 14.11.2.5* Explosion ControlExplosion control shall be provided in accordance with Section 6.10. 14.11.2.5.1When explosion venting is provided, interior walls and other walls of the sterilization room not designed as explosion venting shall be designed to withstand an overpressure of at least 100 psf (4.8 kPa). 14.12 Fire Protection 14.12.1 SprinklersFacilities using ethylene oxide shall be protected by an automatic sprinkler system in accordance with Section 6.11. 14.12.1.1 Ethylene Oxide Storage AreasEthylene oxide storage areas shall be equipped with a deluge system in accordance with NFPA 16.

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Design Requirements For Ethylene Oxide (ETO) Sterilization Areas

Air Changes, Exhaust Requirements, and Ventilation Requirements for ETO Sterilization Equipment Room The ETO sterilization equipment room must have a minimum number of air changes per hour as per Table 4-A and must maintain a negative air balance. All air from the ETO sterilizer equipment room must be exhausted to the outside using a dedicated system or another approved method. The exhaust fan for the dedicated system must be located at the discharge point of the system and identified as the ETO Equipment Room Exhaust. The discharge point must be at least 25 feet (7620 mm) away from any outside intake, operable window, or personnel passage. Aeration units must be ventilated through a non-recirculating dedicated ventilation exhaust system. When the drain is not located in the ETO sterilizer equipment room, ventilation is required by a capture box. Exhaust during cylinder change is required by installing a hood that is part of a dedicated ventilation exhaust system, positioned no more than 1 foot (305 mm) above or behind the point where the change of cylinders takes place. The ventilation of the sterilizer relief valve is required through a pipe connected to the outlet of the relief valve exhausted directly to the outdoors at a point high enough to be away from passersby, and not near any windows that open, nor near any air-conditioning or ventilation air intakes. The system must be designed to capture the ETO when the door is opened following the completion of the sterilization process. A hood or canopy closed on each end should be installed over the sterilization door, connected to a dedicated exhaust ventilation system. Installation of gas line hand valves at the connection to the supply cylinders is required to minimize leakage during cylinder change. An audible and visual alarm system must be installed to alert sterilizer operating personnel if the air flow falls below the design cubic feet per minute (L/s).

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What Medical Devices Can Be Sterilized With Ethylene Oxide?

What Medical Devices Can be Sterilized with Ethylene Oxide? Ethylene oxide (EO or ETO) is a gas commonly used to sterilize medical devices and products chemically. Due to its low-temperature conditions, ethylene oxide sterilization is well suited for medical devices with embedded electronics and medical devices that cannot withstand steam (autoclave) sterilization. Ethylene oxide is also used to sterilize the personal protective equipment and drapes used by doctors and healthcare workers. Medical device types that are sterilized with ethylene oxide range from external wound dressings to implantable stents. Other devices include heart valves, vessel closure devices, catheters, and guidewires. Products combining devices, drugs, and biologics within a single item may also be sterilized using ethylene oxide. How Does the United States Food and Drug Administration (FDA) Define Sterile? Under the strictest definition of sterility, an item or product is sterile when there is the complete absence of viable microorganisms (bacteria, yeasts, viruses, and molds). For regulatory purposes, sterility is defined by acceptance criteria based on calculated contamination probability. An acceptable level of contamination risk for most items is the probability of a single contaminated product out of a million manufactured products. However, sterility criteria may be more stringent or lax depending upon the intended use of the medical device or product. What are Ethylene Oxide and Sterilization by Ethylene Oxide? Ethylene oxide is a potent and highly penetrating alkylating agent. These characteristics make it an extremely effective sterilizing agent. However, at certain levels, ethylene oxide is also capable of causing cancer. Sterilization by ethylene oxide kills microorganisms through exposure to ethylene oxide gas under vacuum and humidity. EO is used either as one hundred percent EO or in combination with carbon dioxide. How Common is Ethylene Oxide Sterilization? Approximately 20 billion medical devices are sterilized with ethylene oxide each year, accounting for about half of sterilized medical supplies in the United States. What Items Cannot be Sterilized with Ethylene Oxide, or are Ethylene Oxide Resistant? Ethylene oxide is not recommended for medical devices with embedded batteries due to the vacuum used during sterilization. Ethylene oxide sterilization is not recommended for materials sensitive to temperatures ranging from 30°C to 60°C or for medical devices made with materials that are sensitive to humidity. Polymers that are resistant to ethylene oxide sterilization are polyolefin resins such as polypropylene (PP), high-density polyethylene (HDPE), and low-density polyethylene (LDPE). What are the Problems with Sterilization by Ethylene Oxide? The primary issue with using ethylene oxide for sterilization is its absorption into certain materials and its reaction with water or other material components to form toxic residual compounds (ethylene oxide, ethylene glycol, and ethylene chlorohydrin). These residual compounds are hazardous both to people and to the environment. Ethylene glycol is formed from the reaction between ethylene oxide and water, while ethylene chlorohydrin is formed from the interaction of ethylene oxide and chloride compounds. Products sterilized with ethylene oxide must meet strict ethylene oxide residual limits to ensure patient safety during medical device and product use. Current ISO 10993-7 ethylene oxide residual limits can be found here.

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Ethylene Oxide Sterilization For Medical Devices

Ethylene Oxide Sterilization for Medical Devices Sterilization is the process of removing, killing, or deactivating all forms of life, including microorganisms or microbes that have the potential to reproduce. Sterile products that undergo sterilization are often chemically or heat sterilized after being placed in their final packaging. The chemical or heat sterilization process after final product packaging is known as terminal sterilization. What is Ethylene Oxide and Sterilization by Ethylene Oxide? Ethylene oxide (EO) is a gas commonly used to sterilize medical devices and products chemically. Ethylene oxide is a potent and highly penetrating alkylating agent, making it an extremely effective sterilizing agent. However, at certain levels, ethylene oxide is also capable of causing cancer. Sterilization by ethylene oxide kills microorganisms through exposure to ethylene oxide gas under vacuum and humidity. EO is used either as 100% EO or in combination with carbon dioxide. What Items Can be Sterilized by Ethylene Oxide? Standard devices and materials sterilized with ethylene oxide are plastic materials (such as plastic devices), gowning materials, heat-labile equipment, and powders. Materials that can be moist heat sterilized can also be sterilized via ethylene oxide. However, if all materials in your device or product are easily sterilized via moist heat, moist heat is the cheaper and easier sterilization option. How is Sterilization by Ethylene Oxide Performed? A typical ethylene oxide sterilization cycle involves loading items into an ethylene oxide sterilization chamber, applying a vacuum, filling the chamber to the desired relative humidity, adding an appropriate concentration of EO gas, and allowing items to rest in the EO gas under vacuum and humidity for the desired exposure time. Afterward, the gas is slowly and safely evacuated from the EO sterilization chamber, and the sterilized items are given ample aeration time to support EO off-gassing. The exposure time for most EO sterilizations is relatively long (around 6 hours), and the gas aeration period is also lengthy, up to 24 hours or more. Factors That Affect EO Sterilization and Lethality Several factors affect EO sterilization and lethality, including gas concentration (ranges from 400 to 1200 milligrams per liter), temperature (most EO cycles range from 50◦C to 60◦C), relative humidity (traditionally ranges from 35% to 80% relative humidity), and exposure time (varies based on materials used, gas concentration, temperature, and relative humidity). Ethylene oxide sterilization is a powerful and reliable solution for ensuring that medical devices and equipment are safe for use by healthcare professionals and patients. However, it's important to understand the risks and limitations associated with this method of sterilization. If you have any questions or concerns, please don't hesitate to contact us.

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Tolerable Exposure Limits For Ethylene Oxide Sterilized Medical Devices

What Are Ethylene Oxide (EtO) Residuals? The primary issue with using ethylene oxide for sterilization is its absorption into certain materials and its reaction with water or other material components to form toxic residual compounds. Ethylene oxide residuals are: Ethylene oxide (EO or EtO) Ethylene chlorohydrin (ECH) Ethylene glycol (EG) Ethylene oxide (EO or EtO) is a commonly used sterilization agent in the medical device industry. However, the sterilization process can leave behind residual compounds that are hazardous to people and the environment. These compounds include ethylene chlorohydrin (ECH), ethylene glycol (EG), and ethylene oxide itself. Residual Compounds Ethylene glycol is formed from the reaction between ethylene oxide and water, while ethylene chlorohydrin is formed from the interaction of ethylene oxide and chloride compounds. What is Ethylene Oxide Residual Testing and Why is it Needed? Ethylene oxide residuals are toxic and carcinogenic to humans at certain levels. Therefore, products sterilized with ethylene oxide must meet strict ethylene oxide residual limits to ensure patient safety during medical device and product use. Current ISO 10993-7 EtO residual limits can be found here. The limits are given for EtO and ECH. Products within the EtO and ECH limits also fall within EG limits. Devices undergoing ethylene oxide (EO) sterilization can fall into more than one EtO limit exposure category based on the duration of contact a medical device has with a patient. Importance of Ethylene Oxide Residual Testing Ethylene oxide residual testing is essential to ensure that medical devices and products are safe for patient use and meet regulatory requirements. Which Products Require Ethylene Oxide Residuals Testing? Any items sterilized using ethylene oxide that come in physical contact with a patient require EtO residuals testing. If your device or product isn't in physical contact with the patient, there is no need to perform EtO residual testing.

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