July 1, 2015 — Almost four years ago, on April 5, 2010, the Food and Drug Administration (FDA) cleared the STERIS System 1E Liquid Chemical Sterilant Processing System, or “SS1E,” for marketing in the U.S.
But before the introduction of the SS1E, there was its once-ubiquitous progenitor: the familiar and similarly named STERIS System 1 Sterile Processing System, or “SS1.”
The STERIS System 1 (“SS1”): Looking back
Arguably the most versatile and successfully marketed instrument reprocessing device ever sold in the U.S., the SS1 was cleared by the FDA almost 25 years ago, in 1988, for the liquid chemical sterilization of many types of surgical instruments, including bronchoscopes, colonoscopes, and other types of flexible endoscopes.
The omnipresent SS1 was an original and unique medical device, and its introduction in the U.S. was as intriguing as its exodus almost 20 years later, in 2009, was unexpected.
The SS1 was the first device (and to date only one of two devices, the second being its successor, the SS1E) for which the FDA granted the previously unknown, if unorthodox, claim of liquid chemical sterilization.
In 2009, however, the FDA began requiring that the SS1 be removed from U.S. healthcare facilities amid a number of regulatory concerns about this device’s design, effectiveness, and labeling.
A paradigm shift
The marketing and sale of the SS1 in the U.S. influenced, if not significantly changed, a number of commonly exercised healthcare paradigms and practices.
Previously, whereas reusable medical instruments were typically cleaned and sterilized in the hospital’s central supply department (or sterile processing department), the SS1’s introduction heralded the relocation of the reprocessing of many of these types of instruments to areas in or near the operating room or endoscopy department.
This notable shift reaped many benefits for hospitals (and other types of healthcare facilities), including availing them the opportunity to reprocess reusable instrumentation within arm’s reach and, to be sure, more quickly, thereby increasing the number of patients that could be treated in a day using one or two expensive surgical instrument sets.
This shift also provided hospitals with the option to sterilize heat-sensitive surgical instruments – again, near their point of use – that otherwise would have to be processed at a remote location using ethylene oxide (EtO) gas or another low-temperature sterilization modality (or be high-level disinfected instead).
For better or worse, SS1’s routine use in the U.S. also impacted another practice:
Whereas surgical instruments had always been wrapped or packaged prior to sterilization (except those instruments that were infrequently “flash sterilized”) to maintain their sterility during transportation and storage, the SS1’s design required that the processed instruments be unwrapped, wet with rinse water, and used immediately.
In its heyday
In its heyday, the SS1 became a household (sorry, a hospital-hold) name.
Many of its features and labeling claims were visionary and trail-blazing, with the SS1 becoming, for a time, a well-timed elixir that addressed and mitigated not only concerns in the 1980s about the transmission of HIV and other blood-borne pathogens during a surgical procedure, but also many of the reprocessing inconveniences and bottlenecks that healthcare managers and staffers inexorably encountered every day.
From the 1990s until this device’s FDA-initiated removal from the U.S. marketplace beginning in 2009, most healthcare staffers with infection-control responsibilities were as aware of the SS1 and its liquid chemical sterilization claim as they were of the device’s ease of use and popularity.
If there was an equivalent in instrument reprocessing to Hush Puppies, the trend-setting SS1 was it – a bona fide healthcare fad.
From a marketing viewpoint, the SS1 was an unrivaled “orange,” with virtually every other type of “point-of-use” instrument reprocessing device remaining a less appealing “apple,” with competitors understandably appearing at times, well, green with envy.
Legal Reviews for Consumers, Hospitals, Manufacturers: Click here to read about Dr. Muscarella’s expertise and legal assessments of the causes of healthcare-associated infections, including “superbug” outbreaks linked to contaminated GI endoscopes and other reusable medical equipment.
The SS1’s discontinuation (2009)
But that was then, and this is now.
On January 20, 2009, STERIS dropped a proverbial bombshell, informing its U.S. customers that it was “discontinuing” sales of the SS1 and its accompanying proprietary single-use sterilant, the S20 Sterilant Concentrate.
This unexpected action was in response to a warning letter the manufacturer had received from the FDA almost a year earlier, on May 15, 2008.
In that letter the FDA concluded that the design of the SS1 had been significantly modified without having received a new regulatory clearance as was required, causing the SS1 to be, according to the FDA, adulterated and misbranded.(1,2)
And, as unexpected as this action were the contents of the FDA’s letter to manufacturers dated February 22, 2010, which claimed that the Agency would also consider misbranded any reusable medical instrument (including rigid endoscopes) whose labeling cited the now rescinded SS1 as a suitable reprocessing method.
(Federal regulations require that manufacturers receive a new regulatory clearance from the FDA whenever a legally marketed medical device undergoes significantly changes that could markedly affect its safety or effectiveness. The consequences of this requirement are several and include the requisite removal of the modified device from the market and from use in the U.S. As with the SS1’s removal, the receipt of a new 510(k clearance, in this instance, for the SS1E, cannot be applied to the modified device.)
By August 2, 2012, the SS1’s use in the U.S. had completely stopped, and with it an era, along with a labeling claim, had ended. … Or had it?
The STERIS System 1E (“SS1E”): Looking forward
As it stated in this same letter (dated January 20, 2009) to U.S. customers notifying them of the SS1’s discontinuation, just two weeks earlier STERIS had applied for a new premarket (or, “510[k]”) clearance to market an updated model that was similar in many respects to the revoked SS1.
This new model — which would address each of the FDA’s expressed concerns with the modified SS1 — would be named the STERIS System 1E Chemical Processing System (SS1E).(1)
As detailed in its 510(k) application, STERIS requested to market the SS1E with the same, coveted claim as the SS1: to achieve liquid chemical sterilization of surgical instruments and flexible endoscopes. Indeed, the predicate device, as required for the SS1E to be cleared via the 510(k) process, was the SS1.
The FDA’s clearance of the SS1E (2010)
With modest fanfare, a little more than a year later, on April 5, 2010, the FDA cleared the SS1E to achieve liquid chemical sterilization of cleaned, immersible, reusable and heat-sensitive both critical and semi-critical instruments, including flexible and rigid endoscopes, used in healthcare facilities. (Click here to read this FDA clearance letter.)
Other than the SS1E and SS1, the FDA has cleared no other device, to date, to achieve liquid chemical sterilization.
[Note: Since the SS1E’s initial clearance in 2010, the FDA has re-cleared this processor, presumably at the responsible behest of the manufacturer in order to remain consistent with FDA regulations, at least four more times, most recently on July 5, 2013.]
The SS1E vs. the SS1
Although the SS1 and SS1E share a number of safety and performance features in common, these two similarly looking, table-top processors are different devices with distinct labeling claims and instructions.
For example, whereas the SS1 had used a single-use formulation called the S20 Sterilant Concentrate (whose use-concentration of peracetic acid was 0.2%), the SS1E was cleared for use with the S40 Sterilant Concentrate, a related, but more diluted (0.18% use-concentration), single-use, peracetic-acid formulation.
Other differences include the SS1E’s cleared use of an ultraviolet (UV) light treatment system to improve, compared to the SS1’s, the microbiological quality of the filtered water used to rinse the processed instrument. And, the SS1E’s chemical exposure time is shorter: 6 minutes, compared to the SS1’s 12-minute exposure time.
But, what differentiates the SS1E most from the SS1 is the former’s omission of two critical features, both of which were indispensable to the latter’s success.
Inherent to the SS1E’s premarket application — as much: (i) to assure conformance of the claim of liquid chemical sterilization with aseptic technique; and (ii) to duplicate the SS1’s both previously cleared labeling claims and, to be sure, marketing success as to meet the healthcare practitioner’s requirements and expectations — was the manufacturer’s request that the FDA also give its regulatory nod to labeling the SS1E:(1,2)
- to produce “sterile” filtered rinse water; and
- to be routinely monitored using a FDA-cleared biological indicator, or “BI.”
Yet, unlike the SS1, which had been cleared by the FDA (in 1988) with the considerably more ideal claim to produce “sterile” water for rinsing, this time, in stark contrast, the FDA disparately cleared the SS1E to produce instead “extensively treated potable water” for rinsing.
And, further, although the FDA cleared a BI for exclusive use with the SS1 in 1996, the Agency demurred and (to date) has not cleared a BI for use with the SS1E.
One notable regulatory lesson
Federal regulations require that manufacturers submit a premarket application to the FDA requesting a new regulatory clearance whenever a medical device used in healthcare setting undergoes significant changes (e.g., design modifications) that could markedly affect its safety or effectiveness.
The consequences of this federal requirement are several and include the following:
As the SS1’s removal from the market beginning in 2009 taught, a manufacturer cannot apply the receipt of a new 510(k) clearance — in this instance, the one the manufacturer received for the SS1E in 2010 — to the modified device (e.g., the SS1) to re-classify this device from adulterated and misbranded to legal.
Rather, the new 510(k) clearance granted to the manufacturer applies only to devices subsequently manufactured and marketed and cannot be retroactively applied to the modified device, whose removal from use in the U.S. becomes mandated and is generally ordered by the FDA.
Liquid chemical sterilization – what exactly is it?
No matter, the absence of these two features from the SS1E’s clearance – namely, the FDA’s decision not to clear the SS1E with a sterile rinse-water claim or with a BI to monitor the processor’s effectiveness and performance – may raise questions, because from some viewpoints these two omissions would seem at odds with the cleared claim of liquid chemical sterilization.
The solution to this puzzle, along with an appreciation for these nuances, may lie in the FDA’s definition of liquid chemical sterilization (see: Box A at the end of this article).
To mitigate confusion among healthcare practitioners, the FDA published a webpage (click here) that defines liquid chemical sterilization and differentiates it from other types of sterilization methods while also answering several anticipated questions that might be asked about this claim.
For instance, in response to the question:
Is liquid chemical sterilization the same as thermal sterilization and, too, low temperature sterilization achieved using a gas, vapor, or plasma?
the FDA states that it “believes that sterilization with liquid chemical sterilants does not convey the same sterility assurance as sterilization using thermal or gas/vapor/plasma low temperature sterilization methods.”
In response to another question:
How really effective is liquid chemical sterilization?
the FDA focuses on this claim’s shortcomings and inherent association with an un-sterile terminal water rinse, however, discussing less what a processor like the SS1E with this claim actually achieves than what its limitations hinder it from necessarily accomplishing.
The rinse water: An Achilles’ heel?
Understanding the term liquid chemical sterilization and what it can, and cannot, achieve requires both a recognition of the effectiveness of the SSE1’s chemical-immersion phase (phase 1) and an acknowledgment of the limitations of this processor’s subsequent water-rinsing phase (phase 2) — see: Box A (at the end of this article).
Briefly, after it is immersed in the SS1E’s solution of diluted peracetic acid, the reusable surgical instrument (or flexible endoscope) is then rinsed with treated, filtered water to remove any potentially toxic chemical residues.
Originating from the healthcare facility’s potable tap water supply, the SS1E’s rinse water is treated using two pre-filters, an UV irradiation system, and two 0.1 micron filter membranes.
Being the apparent Achilles’ heel of the claim of liquid chemical sterilization, the FDA asserts that, while extensively treated, the SS1E’s rinse water “is not sterile,”(3) one consequence of which is significant: that (again, according to the FDA) this processor’s “final processed devices (or instruments) are not sterile” (refer to the FDA letter, dated April 6, 2010, discussing the SS1E’s regulatory clearance one day earlier, on Apirl 5, 2010).
And therein lies the rub:
Even if the SS1E’s chemical-immersion phase (phase 1) were to destroy every microorganism, including blood-borne viruses, on a contaminated instrument’s surfaces, there is the possibility that the instrument could become inadvertently re-contaminated with potentially pathogenic waterborne microorganisms during the processor’s subsequent terminal water-rinsing phase (phase 2), posing an increased risk of disease transmission and patient infection (see: Box A at the end of this article).
Certainly, many instances of patient morbidity and mortality linked to contaminated tap or rinse water used to reprocess surgical and flexible endoscopic instruments have been published during the past 30 years.(4,5)
Although the SS1E’s rinse water is treated, enhanced, and filtered to reduce the risk of the instrument’s re-contamination with opportunistic waterborne microorganisms, it not sterile, according to the FDA.
Because the (SS1E’s) rinse water is not sterile, devices rinsed with this water cannot be assured to be sterile. Furthermore, devices cannot be wrapped or adequately contained during processing in a liquid chemical sterilant.(3) — FDA
And, without its rinse water being sterile, the SS1E’s use would seemingly be limited. Which would explain why the FDA recommends that “the use of liquid chemical sterilants be limited to reprocessing only critical devices that are heat-sensitive and incompatible with sterilization methods such as steam and gas/vapor/plasma low temperature processes.”(3)
[Note: Along with increased competition, whether the FDA’s decision not to clear the SS1E with a sterile rinse-water claim has reduced U.S. demand for this unique, automated point-of-use processor is possible and likely,(6) which suggests that if the FDA were to clear the SS1E in the future with a sterile rinse-water claim and with a BI, this processor’s sale and demand in the U.S. would likely increase significantly.]
Biological indicators vs. spore test strips
A complete discussion of liquid chemical sterilization requires also addressing the types, designs and functions of BIs.
As required by infection-control guidelines and the standard of care, BIs are routinely used in the clinical setting to validate that the sterilizer achieved the conditions required for sterilization (at least at the site inside the sterilizer where the BI was physically placed) to a specified sterility assurance level, or SAL, generally of 10-6.
There are several different types of BIs, which, like sterilizers, are themselves required to be cleared by the FDA before they can be marketed in the U.S.
The design of one familiar type of BI, in particular, features a strip of filter paper that is impregnated with at least 105 resistant bacterial endospores and enclosed in a glassine envelope.
As it applies to the SS1E, however, the definition of a BI may be unclear, like the claim of liquid chemical sterilization.(3)
Namely, in response to yet a third question (which the FDA listed on its aforementioned webpage designed to answer some of the anticipated questions that healthcare practitioners might ask about the SS1E – click here):
Can liquid chemical sterilization, like all other sterilization methods, be monitoring using a BI?
the FDA replies that BIs “are not appropriate or required for monitoring liquid chemical sterilization process (sic),” adding that the FDA “has not cleared any biological indicators for monitoring liquid chemical sterilization process.”(3)
Yet, two years after the clearance of the SS1E, the FDA, on March 30, 2012, granted the manufacturer the legal right to market a “spore strip test” — which on its face is the same as a BI — for exclusive use with the SS1E (click here).
The solution to this apparent inconsistency may again lie in the FDA’s definition of the term: According to the FDA, a spore strip test is a type of medical device that is distinctly different from a BI (even though, as noted previously, the designs of some BIs feature a spore strip, and therefore BIs and spore strips had been terms in the past often used interchangeably).(7-9)
In short, whereas the FDA has designated FDA-cleared BIs for use with bona fide sterilizers, now, by way of the de novo process and classification, the FDA has cleared a spore strip test for the exclusive monitoring of liquid chemical sterilization processes (i.e., the SS1E).
A de novo classification is intended for any new type of device that the FDA has determined is not substantially equivalent to a predicate device (as required of the 510[k] clearance process) and therefore would otherwise require a more time-consuming premarket approval (PMA) to be sold in the U.S.
[Note: As discussed herein, several aspects of the claim of liquid chemical sterilization are not obvious or clear-cut. On March 30, 2012, the FDA granted the manufacturer the legal right to market a spore strip test, via a de novo classification, for exclusive use in the SS1E (click here).(9) For a continuation of this discussion, the reader is directed to Box B at the bottom of this article.]
The following recommendations are provided to healthcare practitioners considering the use of a processor labeled to achieve liquid chemical sterilization:
1. Ensure a clear understanding of the definition, benefits and limitations of liquid chemical sterilization.
- For example, understand that the filtered, treated rinse water associated with the claim of liquid chemical sterilization — while labeled to be of an enhanced quality — is not sterile. (Therefore, once terminally rinsed with water, the processed surgical instrument would not be considered sterile, although, depending on a number of factors and just like with high-level disinfection, it would not necessarily be unsafe for clinical use).
- According to a magazine article, it is for this and some other reasons that “the FDA cleared the System 1E (SS1E) as a ‘processor’ and not as a ‘sterilizer’,” adding that “a liquid chemical sterilant process should not be your first choice for items that come in contact with compromised tissue.”(7,10)
- Review the FDA’s definition of “liquid chemical sterilization” (see reference No. 3).
2. Ensure a clear understanding of the differences between a spore strip test and a BI.(7-9)
- Read the FDA’s published document entitled “Evaluation of Automatic Class III Designation (De Novo) for the STERIS Verify Spore Test Strip for S40″ by clicking here.(8)
- Whereas traditional BIs are used to monitor the effectiveness of FDA-cleared sterilizers, spore strip tests are used instead to evaluate the effectiveness of liquid chemical sterilization processes and to confirm that the liquid sterilant (e.g., the SS1E’s S40 Sterilant Concentrate) is sporicidal.(7-9)
- According to the FDA, a spore strip test’s “no growth” result “does not confirm the expected full performance” of of processor.(8,9)
- Use of a spore test strip to monitor the SS1E is optional. The SS1E’s manufacturer recommends, however, that the spore test strip be used daily, namely, during the first processing cycle of the day.(7)
- Click here to read Dr. Muscarella’s related article “Types and Characteristics of Biological Indicators for Monitoring Sterilization Processes.“
3. Use chemical indicators (“CIs”) to monitor processes labeled to achieve liquid chemical sterilization.
- According to the FDA,(6) “chemical indicators (CIs) are appropriate and are required for monitoring the minimum required concentration of most liquid chemical sterilants.”
- The manufacturer of the SS1E recommends that a CI be used during each processing cycle, to confirm that the S40 sterilant’s peracetic acid is present and active.(7)
- Periodically contact the manufacturer for updated instructions regarding use of the SS1E and its associated accessories, including CIs.
4. Immediately use any instrument processed using a device labeled to achieve liquid chemical sterilization. (Delays in the processed instrument’s use can pose an increased risk of bacterial re-contamination.)
- Drying the instrument prior to its use (in a manner that does not result in its re-contamination) may be considered and is often advisable. (Rinsing a flexible endoscope’s internal channels with 70% alcohol followed by forced air is commonly employed to achieve drying.)
- Moreover, instruments processed by liquid chemical sterilization cannot be wrapped or adequately contained.(6) According to the FDA, “this means that there is no way to maintain sterility once devices have been processed.”(6)
- If the processed instrument is not used immediately (e.g., its use is delayed, or the instrument is stored at the end of the day), the instrument would presumably require reprocessing again prior to its reuse. (Contact the manufacturer for updated instructions.)
- Click here to read Dr. Muscarella’s related article “The Safe Storage of Gastrointestinal Endoscopes.“
- Similarly, click here to read Dr. Muscarella’s other related article “Infections of Pseudomonas aeruginosa linked to Flexible Endoscopes: The Importance of Endoscope Drying.”
5. Service and maintain the SS1E as recommended by its manufacturer.
- Replace (as instructed by the manufacturer) the SS1E’s water filters and any other associated equipment (e.g., the UV light), to ensure the rinse water’s highest quality possible.
- If a bacterial outbreak is detected, culture the processor’s water filters and, as required, the processor’s internal components, along with other environmental surfaces, to determine whether any are contaminated with the outbreak’s strain of bacteria.
- Perform all necessary preventative maintenance procedures (e.g., periodical cleaning of the SS1E’s internal components and surfaces) as instructed by its manufacturer.
6. Steam sterilize all surgical instruments (e.g., reusable biopsy forceps) whose labeling does not contraindicate the use of moist steam under pressure.
- Do not use immediate use steam sterilization (IUSS) (or flash sterilization) to process surgical instruments except during an emergency situation.
- Click here to read Dr. Muscarella’s related article: “Flash or Immediate Use Steam Sterilization: A Position Statement.”
- UnderstandthatanyprocessorassociatedwiththeclaimofliquidchemicalsterilizationisdistinctfromIUSS or a “flash”sterilizer.
- Whereas IUSS uses steam, can be monitored using a BI, and renders instruments sterile, liquid chemical sterilization cannot be monitored using a BI (instead, a spore strip test is used) and yields processed instruments that are wet with rinse water and may not be sterile.
Questions: Questions may be address to this article’s author at: Larry@LFM-HSC.com
Article by: Lawrence F Muscarella, PhD; posted 11/7/2014, Rev A; updated 11/11/2014, Rev A.
BOX A: Liquid chemical sterilization’s two phases.
The FDA’s acceptance on the one hand of the claim of liquid chemical sterilization, while on the other asserting that the water used to rinse the processed surgical instruments following their chemical immersion “is not sterile,”(3) can be confusing and therefore warrants further discussion.
Such a seemingly dichotomous clearance by the FDA appears to be a consequence of the Agency having divided the process of liquid chemical sterilization, at least as it applies to the SS1E, into two distinct parts.(3,7)
Namely, the FDA might agree that a type of sterilization (i.e., liquid chemical sterilization) is achieved during the SS1E’s singular chemical immersion phase (phase 1), but the Agency has concluded that there remains the possibility that this outcome would be compromised once the processed instrument is subsequently rinsed with treated, but not sterile, water (phase 2) just prior to its clinical use.
The manufacturer’s instruction that the processed (and wet) instrument be used “immediately” after the SS1E’s completed cycle is intended to mitigate the potential risk of infection due to having rinsed the instrument with un-sterile water.(10)
BOX B. The FDA de novo classification vs. a 510(k) clearance: A distinction with a regulatory difference.
Like the claim itself, several other aspects of liquid chemical sterilization are similarly not obvious or clear-cut.
For example, on March 30, 2012, the FDA granted the manufacturer the legal right to market a spore strip test — which is now a type of medical device that the FDA distinguishes from a biological indicator, or BI, which is another type of medical device that requires a 510(k) clearance before it can be marketed in the U.S.— for exclusive use in the SS1E (click here).(7-9)
According to the FDA, a de novo classification was required for this specific spore strip test because there was no legally marketed device that was substantially equivalent to it as regulations require of a device to receive instead a 510(k) clearance.(8,9)
The de novo classification of this spore strip test raises two points, however:
First, this type of regulatory classification notwithstanding, there was a legally marketed spore strip that had been: (i) cleared three times within the past 20 years by the FDA as a biological monitor, or BI, and (ii) used for several years in U.S. healthcare facilities to monitor the liquid chemical sterilization claim of the SS1, the SS1E’s predecessor (or substantially equivalent device).
Therefore, the FDA’s rationale for concluding that there was no previously marketed device in the U.S. that was substantially equivalent to the SS1E’s spore strip test, thereby requiring that this device receive a de novo classification (instead of a 510[k] clearance), is unclear.
For more details and clarity, the reader may review the three aforementioned 510(k) clearances received for the BI used to monitor the SS1: K960570, K060568, and K062269, although it is noted that these three clearances are no longer listed in the FDA’s current 510(k) database. (For reference, the FDA’s de novo notification letter granted to its manufacturer for use of a spore strip test in the SS1E can be read by clicking here.)
And, second, though it was required of the SS1E’s spore strip test, it is unclear why the FDA did not similarly require, using the same rationale, a de novo classification (instead of a 510[k] clearance) of the SS1E prior to its marketing in the U.S.
Indeed, at the time of the SS1E’s clearance in 2010, the removal of the SS1 (i.e., the SS1E’s predicate device) from U.S. healthcare facilities had already begun one year earlier, in 2009. Therefore, in 2010 when the FDA granted the SS1E a 510(k) clearance, there was no legally marketed device in the U.S. that was substantially equivalent to (and therefore was the predicate for) the SS1E, the requirement that there be one notwithstanding.
- STERIS Corp. Important Notice. Dated: January 20, 2009. Mentor, OH. [Letter] (Click here)
- STERIS Corporation submits new sterilization system to FDA and announces developments on System 1 warning letter. FirstCall. Mentor, OH. January 20, 2009.
- Food and Drug Administration (FDA). Liquid chemical sterilization. A webpage. Last updated: 06/04/2014 (Click here)
- Muscarella LF. Contribution of tap water and environmental surfaces to nosocomial transmission of antibiotic-resistant Pseudomonas aeruginosa. Infect Control Hosp Epidemiol. 2004 Apr;25(4):342-5.
- Muscarella LF. Application of environmental sampling to flexible endoscope reprocessing: the importance of monitoring the rinse water.Infect Control Hosp Epidemiol. 2002 May;23(5):285-9.
- Smith RL. STERIS plans to close a local plant and eliminate 100 jobs. The Plain Dealer March 27, 2014 (updated on-lone: March 28, 2014).
- Young M. Spore test for liquid chemical sterilant processing system. OR Manager 2012 November;28(11):1-3.
- Food and Drug Administration (FDA). Evaluation of automatic class III designation (de novo) for the STERIS Verify spore test strip for S40. K100049 De Novo Petition (click here).
- Food and Drug Administration (FDA). STERIS Verify spore test strip for S40. De novo clearance. March 30, 2012 (click here).
- Food and Drug Administration (FDA). 510(K) Summary for SYSTEM lE Liquid Chemical Sterilant Processing System. April 5, 2010. (FDA Clearance No. K090036.)