On a fact-finding mission?
Ethylene oxide sterilization is a big topic to put your arms around – we know, we’ve done it! Below are some great studies and reference materials to get you started. Your quest for knowledge on the topic may also take you to Why EO, Our Technology and News.
All studies conducted by Andersen Scientific, the contract sterilization and laboratory arm of Andersen. In many cases, researchers created unrealistically unfavorable circumstances to see what would happen in the very worst-case scenario. Studies below often reference OSHA’s short-term exposure limit (STEL). For ethylene oxide, the OSHA STEL is 5 ppm. Please click on the Download link to see the full study.
Anprolene Door Left Open
In this worst-case scenario study an Anprolene AN74i was operated with its door left open in a room without air circulation and with higher-than-normal amounts of gas. Air was tested less than 10 inches from the liner bag. The study showed it took 75 minutes to reach the OSHA short-term exposure limit (STEL). Researchers concluded there is no immediate danger of operator exposure if the AN74i sterilizer door is not closed upon beginning a cycle.
Anprolene Purge Probe Efficacy
This study documents the effectiveness of the purge probe in aerating the contents of the liner bag at the end of a sterilization cycle. Within 45 minutes of the start of the 2-hour purge cycle, the EO samples decreased from approximately 40,000 ppm to 4 ppm – a reduction of 99.9%, and a measurement below the OSHA STEL (5 ppm). It can be concluded that by the end of the 2-hour purge cycle, the EO levels will be well below 4 ppm.
Anprolene Pump Failure
In this worst-case scenario study an Anprolene AN74i was operated in a room without air circulation and with a simulated ventilation pump failure when gas concentration was highest. Air samples were taken when the pump “failed” and 40 min later. At both points, gas concentrations were well below OSHA STEL. Researchers concluded operators are not at risk of EO exposure should the vent pump fail during a AN74i cycle, even at times of peak concentration.
Anprolene Compromised Bag
In this study an Anprolene AN74i was operated in a room without air circulation, with a 1 inch cut in the liner bag. Air was sampled at the operator’s breathing zone, within 4 feet of the cabinet. EO levels were well below OSHA STEL. This study shows if the sterilization bag is compromised, the operator is not at risk for EO exposure.
Anprolene Operator Exposure
In this worst-case study an Anprolene AN74i was operated in a room without air circulation and more than the standard amount of gas. Two different methods of measuring personal exposure were used following the manufacturers guidelines. Both methods returned results well below the OSHA short-term exposure limit (STEL).
Accidental Ampoule Activation
In this worst-case scenario study an ampoule was broken and air tested 18 inches away. It took 11 minutes before the OSHA short-term exposure limit (STEL) was reached. The study shows there is no immediate danger to an operator from an accidental activation of a gas ampoule outside of a sterilization liner bag.
EOGas 4 Efficacy
In this study the EOGas 4 produced a negative BI 100% of the time at 90 minutes into the cycle. The EOGas 4 achieved a 6-log reduction over the 90 minutes, so standard practice is to assume it will achieve the SAL of 10-6 over the full three-hour exposure cycle required for terminally sterilized medical devices.
EOGas 4 Operator Exposure
In this worst-case scenario study the EOGas 4 was operated in a room without air circulation. In one scenario, post-cycle, the items were given additional aeration time in the lab. In another scenario, they were removed from the lab. In both cases, air samples stayed well below OSHA STEL.
EOGas 4 Residuals
Post-cycle, EO residuals in common medical device materials were measured (latex, paper, silicone, nitrile, hard PVC, polypropylene, polycarbonate, stainless steel and glass). All tested materials were at least twenty-eight (28) times below the ISO residual limits for limited exposure medical devices.
EOGas 3 Lumen Length
This study shows that the EOGas 333 sterilizer’s standard 16-hour cycle can be used effectively to sterilize 60 inch stainless steel lumens in diameters from 1 mm to 5 mm with one end closed. For lumens that are open at both ends, the effective lumen length may be doubled to 120 inches.
EOGas 3 Operator Exposure
In this study the EOGas 310 and EOGas 333, both equipped with Andersen emissions abators, emitted significantly less than OSHA’s short-term exposure limit (STEL) and time weighted average (TWA) limits – even when the larger unit was opened when gas concentration would be at the highest.
Laptop Function Study
In this study a laptop was sterilized with more gas than normal in an Anprolene AN74i and an EOGas 333 sterilizer. In both cases, the cycle passed on a dosimeter, the BI was negative and, after 24-hour aeration, the laptop’s performance was not impaired. Note: Battery must be removed and packaged separately.