Ethylene Oxide Sterilization Research Articles

Characterization of a reversible thermally-actuated polymer-valve: A potential dynamic treatment for congenital diaphragmatic hernia.

BackgroundCongenital diaphragmatic hernia (CDH) is a fetal defect comprising an incomplete diaphragm and the herniation of abdominal organs into the chest cavity that interfere with fetal pulmonary development. Though the most promising treatment for CDH is via interventional fetoscopic tracheal occlusion (TO) surgery in-utero, it has produced mixed results due to the static nature of the inserted occlusion. We hypothesize that a suitable noninvasively-actuatable, cyclic-release tracheal occlusion device can be developed to enable dynamic tracheal occlusion (dTO) implementation.ObjectiveTo conduct an in-vitro proof-of-concept investigation of the construction of thermo-responsive polymer valves designed for targeted activation within a physiologically realizable temperature range as a first step towards potential development of a noninvasively-actuatable implantable device to facilitate dynamic tracheal occlusion (dTO) therapy.MethodsSix thermo-responsive polymer valves, with a critical solution temperature slightly higher than normal physiological body temperature of 37°C, were fabricated using a copolymer of n-isopropylacrylamide (NIPAM) and dimethylacrylamide (DMAA). Three of the valves underwent ethylene oxide (EtO) sterilization while the other three served as controls for EtO-processing compatibility testing. Thermal response actuation of the valves and their steady-state flow performances were evaluated using water and caprine amniotic fluid.ResultsAll six valves consisting of 0.3-mole fraction of DMAA were tested for thermal actuation of caprine amniotic fluid flow at temperatures ranging from 30–44°C. They all exhibited initiation of valve actuation opening at ~40°C with full completion at ~44°C. The overall average coefficient of variation (CV) for the day-to-day flow performance of the valves tested was less than 12%. Based on a Student t-test, there was no significant difference in the operational characteristics for the EtO processed versus the non-EtO processed valves tested.ConclusionsWe successfully fabricated and demonstrated physiological realizable temperature range operation of thermo-responsive polymer valves in-vitro and their suitability for standard EtO sterilization processing, a prerequisite for future in-vivo surgical implantation testing.

Impact of Ethylene Oxide Sterilization of Polymer-Based Prefilled Syringes on Chemical Degradation of a Model Therapeutic Protein During Storage

Materials from prefilled syringe systems—such as silicone oil, tungsten, glass, and rubber—may enhance therapeutic protein aggregation and particle formation. Also, the sterilization method used for syringes may impact aggregation and chemical degradation of biologics during storage. Syringes are generally sterilized by radiation, ethylene oxide gas (EO), or steam. Among the sterilization methods, EO has the potential to cause chemical degradation by the formation of adducts with susceptible amino acid residues in the protein. In this study, EO- and steam-sterilized syringes were compared to determine the influence of residual EO on human serum albumin (HSA) degradation. Although the amount of residual EO in the EO-sterilized syringes was less than 220 μg/syringe, well below the International Organization for Standardization limit, EO adduction to cysteine (Cys) and methionine (Met) in HSA was observed by liquid chromatography and mass spectrometry analysis. The EO adduct ratio of HSA stored for 2 weeks in EO-sterilized syringes was about 45%. In contrast, no chemical degradation was observed in HSA formulation stored in steam-sterilized syringes. Because of the propensity of EO to readily form adducts with proteins, an alternative to EO sterilization should be used for prefilled syringes that will be used for therapeutic protein products.

Effect of Ethylene Oxide Sterilization and Accelerated Ageing on the Physical and Mechanical Properties of Beech, Oak, and Elm Wood: Part 2

The effect of ethylene oxide (EO) sterilization and/or accelerated ageing on impact bending strength (IBS), tensile strength along and across the fiber (TSALF and TSACF), ultimate flexural strength along and across the fiber (FSAL and FSAC), and splitting resistance (SR) was tested in bulk and veneer wood. The IBS was greatly increased in beech but decreased in some oak samples. The EO treatment followed by ageing caused the TSACF to increase in bulk beech and to decrease in bulk oak. The EO treatment decreased the TSALF values in bulk oak, beech, and elm veneer. However, beech veneer samples exhibited increased TSALF. The ageing of EO treated samples decreased the TSALF values for veneers (oak and beech), while both bulk samples increased. A notable decline was observed due to EO treatment of oak and beech, along with post ageing decline for oak samples in FSAC values only. The FSAL values decreased after ageing of EO treated and untreated samples (oak and beech), while a post EO treatment decline was observed in oak samples only. The SR (Rw) values decreased in EO-only treated oak wood and increased in EO treated and aged samples (oak and beech).

Plasma-Activated Substrate with a Tropoelastin Anchor for the Maintenance and Delivery of Multipotent Adult Progenitor Cells.

Conventional wound therapy utilizes wound coverage to prevent infection, trauma, and fluid and thermal loss. However, this approach is often inadequate for large and/or chronic wounds, which require active intervention via therapeutic cells to promote healing. To address this need, a patch which delivers multipotent adult progenitor cells (MAPCs) is developed. Medical-grade polyurethane (PU) films are modified using plasma immersion ion implantation (PIII), which creates a radical-rich layer capable of rapidly and covalently attaching biomolecules. It is demonstrated that a short treatment duration of 400 s maximizes surface activation and wettability, minimizes reduction in gas permeability, and preserves the hydrolytic resistance of the PU film. The reactivity of PIII-treated PU is utilized to immobilize the extracellular matrix protein tropoelastin in a functional conformation that stably withstands medical-grade ethylene oxide sterilization. The PIII-treated tropoelastin-functionalized patch significantly promotes MAPC adhesion and proliferation over standard PU, while fully maintaining cell phenotype. Topical application of the MAPC-seeded patch transfers cells to a human skin model, while undelivered MAPCs repopulate the patch surface for subsequent cell transfer. The potential of this new wound patch as a reservoir for the sustained delivery of therapeutic MAPCs and cell-secreted factors for large and/or non-healing wounds is indicated in the findings.

Effect of Ethylene Oxide Sterilization and Accelerated Ageing on the Physical and Mechanical Properties of Beech, Oak, and Elm Wood: Part 1

Effects of ethylene oxide (EO) treatment on library and museum furniture were investigated. Three treatments (accelerated ageing, EO treatment, and EO treatment followed by accelerated ageing) were applied to understand the effects on physical and mechanical properties of the common furniture woods. The Buchholz indentation test/micro-hardness (MH), color and gloss, Brinell hardness/macro-hardness (BH), and surface roughness were tested. The MH of oak and beech samples was not noticeably affected by any of the treatments, whereas elm samples showed some effects. For all types of wood, color was affected by EO treatments, but not considerably affected by ageing. Gloss significantly decreased with EO and accelerated ageing treatments for all samples. In BH measurements, ageing caused a decrease in hardness for both the control and EO treated samples, although this affect was not marked in beech samples. The EO treatment caused a decrease in hardness for beech and elm samples, but no major effect was observed in oak samples. There was a significant effect on the Ra values (arithmetic average of the absolute values of the roughness profile ordinates) in the aged groups of beech and oak samples, as well as oak samples that received both EO treatment and ageing.

The influence of sterilization on properties of polyurethane/polylactide blend

The biodegradable polyurethane/polylactide blend was treated with low temperature hydrogen peroxide plasma, ethylene oxide and immersing in ethanol combined with ultraviolet radiation. The samples sterilized by hydrogen peroxide and ethylene oxide stood practically unaffected, while UV/EtOH caused distinct changes in their mechanical properties. For example the signifficant reduction of tensile strength occured, elongation at break became twice lower, while the Young's modulus increased by 23%. The XPS measurements showed that after all types of treatment atomic carbon and nitrogen concentrations in the surface layer was slightly lower than in the bulk. Instead the surface layer was more enriched with oxygen. Ethylene oxide sterilization caused that both surfaces became more hydrophobic i.e. the contact angle increased about 15% for the top surface and 8% for the bottom surface, respectively. Sterilization with ethanol and UV radiation changed the nature of surface into more hydrophilic, the contact angle of the top surface was reduced about 6% and the bottom about 24%. The FT-IR spectra of all sterilized samples were recorded and discussed. From all used sterilization methods only hydrogen peroxide plasma is fully suitable for biodegradable PU/PLA blend.

The effect of ethylene oxide sterilization on electrospun vascular grafts made from biodegradable polyesters

The study describes the detailed examination of the effect of ethylene oxide sterilization on electrospun scaffolds constructed from biodegradable polyesters. Different fibrous layers fabricated from polycaprolactone (PCL) and a copolymer consisting of polylactide and polycaprolactone (PLCL) were investigated for the determination of their mechanical properties, degradation rates and interaction with fibroblasts. It was discovered that the sterilization procedure influenced the mechanical properties of the electrospun PLCL copolymer scaffold to the greatest extent. No effect of ethylene oxide sterilization on degradation behavior was observed. However, a delayed fibroblast proliferation rate was noticed with concern to the ethylene oxide sterilized samples compared to the ethanol sterilization of the materials.

Duodenoscope reprocessing practice patterns in U.S. endoscopy centers: a survey study

After recent outbreaks of duodenoscope-related infections from multidrug-resistant organisms (MDRO), the United States Food and Drug Administration (FDA) recommended implementing 1 or more of 4 enhanced reprocessing measures in addition to updated manual cleaning methods and high-level disinfection (HLD). The implementation of these techniques in endoscopy facilities and provider opinions regarding reprocessing priorities remain unknown. Physicians, nurse managers, nurses, and infection control staff at endoscopy units performing ERCP in the United States were surveyed to assess current institutional practices and individual opinions regarding future reprocessing solutions. A total of 249 distinct institutions participated in the survey. Of these, 223 (89.6%) implemented at least 1 of the 4 supplemental reprocessing methods after MDRO outbreaks. Overall, 63% of centers used repeat HLD, 53% performed surveillance microbiological culturing, 35% used liquid chemical sterilization, and 12% used ethylene oxide sterilization. Thirty-seven centers (15%) routinely screened patients for MDRO. Forced-air drying after reprocessing was used by 47.8% of centers. Fifty percent of individual respondents, including 58.6% of physicians, believed that redesign of the duodenoscope is the best long-term reprocessing solution. The majority (55.1%) identified efficacy to be the single most important factor in selecting a reprocessing technique. Although most endoscopy centers have implemented enhanced duodenoscope reprocessing techniques, there is a large variation in practice. Most providers believe that duodenoscope redesign and identifying reprocessing techniques with maximal efficacy are the long-term priorities. Improved adherence to forced-air drying in duodenoscope reprocessing is needed.

Improving the practicality and safety of artificial corneas: Pre-assembly and gamma-rays sterilization of the Boston Keratoprosthesis

PurposeTo make the Boston keratoprosthesis (B-KPro), together with its carrier corneal graft, more easily procured, transported and stored, as well as less expensive, easier for the surgeon to implant and safer for the patient, it is proposed that the B-KPro-graft combination be pre-assembled by an expert technician, followed by sterilization with gamma ray irradiation (GI) allowing long-term storage at room temperature. For this to be possible, it must be shown that the B-KPro itself (not only the graft) remains unharmed by the irradiation. MethodsPolymethyl methacrylate (PMMA) discs and B-KPros were submitted to either ethylene oxide sterilization or different doses of GI. Cell biocompatibility, mechanical strength and optical quality were evaluated. The feasibility of assembling the B-KPro to a corneal graft, and gamma-radiate afterwards, was also assessed. ResultsThere were no differences in cell biocompatibility between the samples. The optical evaluation showed high levels of transparency for all the groups. The absorbance of ultraviolet was higher for the groups treated with GI. The mechanical evaluation by nanoindentation showed no alterations of the PMMA discs after GI. The flexure test revealed a similar mechanical behavior. Technically, pre-assembly and GI of the B-KPro revealed no problems. ConclusionsSterilization of B-KPro using GI has no detrimental influence on the device. The pre-assembly of B-KPro to a donor cornea, followed by gamma sterilization, emerges as an efficient and safe procedure.

The Effect of Different Sterilization Methods on Polypropylene Syringes

This presents the influence of gamma irradiation on Pharmacopeia specifications, mechanical and flow parameters of polypropylene (PP) syringes. There has been significant progress in the terminal sterilization of single-use, disposable medical devices with gamma radiation sterilization due to the growing awareness of toxic residues during the ethylene oxide (EtO) sterilization. PP is a widely used polymer for the production of syringes because of its excellent mechanical and thermal properties and has expanded continuously over the last decade. Although 25 kGy was generally recommended for the gamma radiation sterilization of medical products, this radiation dose is high enough to produce substantial damage. Electron spin resonance (ESR) characteristics of irradiated syringes were also studied at normal (25 °C, 60% relative humidity) and accelerated (40 °C, 75% relative humidity) stability test conditions. It was found that the chemical and radiolytic changes and sterility assurance levels (SAL) after gamma radiation sterilization were different in PP syringes. It was shown that for two commercial syringes, E1 and E3, a SAL of 10−4 could be attained with only 10 kGy, with there being less detrimental radiation effects on E1. The differences in the radiosensitivity of the propylene syringes could be due to the different formulations and manufacturing processes. The results indicated that a commercial syringe, identified as E1 could be safely sterilized with gamma irradiation as the radicals decay over a period of days under normal conditions and quenched much faster under stability conditions. Furthermore, ESR technique could be used successfully in monitoring the radiosterilization of this material. Additionally, the confirmation and validation of the SAL doses which are below 25 kGy, will decrease the time and cost of the sterilization with less damaging effects of ionizing irradiation.

Cost Analysis of Re-Sterilization Procedure of Re-Usable Devices in a Hospital

Aim: To analyse the costs and recommend rectification in functioning of CSSD for qualitative delivery of patient care. Objectives: Assess the effectiveness of sterilization procedures and calculate the cost of re-sterilization of the batch which failed quality indicators tests. Method: It was observational prospective study done by random sampling technique for selecting sterilization cycles. In the present study, 1451 cycles of steam sterilization, 780 cycles of plasma sterilization and 312 cycles of ethylene oxide sterilization was observed. Results: The study revealed that 66 cycles of steam sterilization and 21 cycles of plasma sterilization failed the parameters of quality indicators. The total cost incurred on the hospital for re-sterilization was found to be Rs. 4,18,800/. Conclusion: The study emphasized the need of training of the CSSD technician for implementing the appropriate use of quality indicators for efficient sterilization. The study also focussed on the need of in-house bank of frequently replenished spare parts and a planned maintenance program for sterilization equipment. Key words: Sterilization Procedures, Training of Central sterile and supply department employees, Quality Indicators, Costing Analysis.

Comparing sterilization efficacy and cost implications of various gas-based sterilization methods used in a Central Sterile Supply Department: A short review

Low-temperature sterilisation basically depends on four types of sterilisation systems, i.e. gamma irradiation, Ethylene oxide sterilisation, Hydrogen peroxide (H2O2) and steam Formaldehyde sterilisation. The article has been described on the basis of these low-temperature sterilisation systems with their infrastructural ease, regulatory requirements, cycle time, sterilisation efficacy, safety features and cost. In our experience, the H2O2-based sterilisation system is superior over the other methods due to its easy installation and cycle time that helps to perform more procedure in a day and reduces infection by providing terminal sterilisation (ready-to-use) processes. Besides due to the short cycle time of the H2O2 steriliser, it requires fewer inventories and saves cost to the management in the long run.

Characterization and application of azo dye (E)-N-phenyl-4-(thiazole-2-yldiazenyl)aniline (PDA) for biomedical sterilization.

Sterilization is the certain and absolute decontamination of microorganisms totally from all manner of alive and active species. Sterilization devices used in the sterilization processes are between laboratory and external patient application devices of biomedical device technology, and they are designed to remove equipments from germs. The application potential of hetarilazo indole based azo dyes in the biomedical sterilization are known and azo dyes come into prominence in this class because of simplicity of their synthesis and procurement of low-cost raw materials. In this work, the application potential of a novel synthesized azo dye, (E)-N-phenyl-4-(thiazole-2-yldiazenyl)aniline was investigated as an indicator in the biomedical sterilization performing the electrochemical and spectroscopic characterizations. The application of indicator was tested by ethylene oxide, hydrogen peroxide and peracetic acid sterilization techniques introducing into various sterilization rolls.

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A Novel Protocol Obviates Endoscope Sampling for Carbapenem-Resistant Enterobacteriaceae: Experience of a Center with a Prior Outbreak.

Numerous published outbreaks, including one from our institution, have described endoscope-associated transmission of multidrug-resistant organisms (MDROs). Individual centers have adopted their own protocols to address this issue, including endoscope culture and sequestration. Endoscope culturing has drawbacks and may allow residual bacteria, including MDROs, to go undetected after high-level disinfection. To report the outcome of our novel protocol, which does not utilize endoscope culturing, to address our outbreak. All patients undergoing procedures with elevator-containing endoscopes were asked to permit performance of a rectal swab. All endoscopes underwent high-level disinfection according to updated manufacturer's guidance. Additionally, ethylene oxide (EtO) sterilization was done in the high-risk settings of (1) positive response to a pre-procedure risk stratification questionnaire, (2) positive or indeterminate CRE polymerase chain reaction (PCR) from rectal swab, (3) refusal to consent for PCR or questionnaire, (4) purulent cholangitis or infected pancreatic fluid collections. Two endoscopes per weekend were sterilized on a rotational basis. From September 1, 2015 to April 30, 2016, 556 endoscopy sessions were performed using elevator-containing endoscopes. Prompted EtO sterilization was done on 46 (8.3%) instances, 3 from positive/indeterminate PCR tests out of 530 samples (0.6%). No CRE transmission was observed during the study period. Damage or altered performance of endoscopes related to EtO was not observed. In this pilot study, prompted EtO sterilization in high-risk patients has thus far eliminated endoscope-associated MDRO transmission, although no CRE infections were noted throughout the institution during the study period. Further studies and a larger patient sample will be required to validate these findings.

Chemical composition and morphology study of bovine enamel submitted to different sterilization methods.

The morphology and chemical composition of enamel submitted to different sterilization methods was studied. X-ray photoelectron spectroscopy (XPS), field emission gun scanning electron microscopy (FEG-SEM), and energy-dispersive X-ray spectroscopy (EDS) were performed to evaluate 50 bovine enamel specimens sterilized using four methods: microwaving (MI), gamma irradiation (GI), ethylene oxide (EO), and steam autoclave (SA). Non-sterilized specimens were used as control. XPS indicated that the concentration of P (phosphorus), CO3 (carbonate), and CO3/P was not changed in all groups. GI produced no significant change on elemental composition. SA produced the major decrease in calcium (Ca), Ca/P ratio, and increase in N (nitrogen). MI was found to decrease Ca, Ca/P ratio and O (oxygen), and increase in C (carbon) and N. EO produced decrease in Ca and O with increased C concentration. FEG-SEM revealed surface and in-depth morphological changes on SA specimens. Minor surface alterations were observed for EO and for MI groups, and no alteration was observed on GI group. EDS indicated no difference on elemental composition of enamel bulk among groups. SA produced mineral loss and morphological alterations on surface and in depth. MI and EO sterilization caused mineral loss showing only slight alteration on enamel surface. GI sterilization preserves the morphological characteristics of enamel. The sterilization methods could be classified from lower to high damage as GI<MI<EO<SA. This is a comprehensive comparative study where different methods for enamel sterilization were investigated in terms of chemical changes. The results presented here may help researchers to choose the most appropriate method for their research setting and purpose.

Comparative Study of the Surface Properties and Cytocompatibility of Plasma-Treated Poly-ε-Caprolactone Nanofibers Subjected to Different Sterilization Methods

A major challenge in the design of tissue-engineered scaffolds is mimicking the architectural and functional properties of the extracellular matrix (ECM) and preserving these properties after sterilization. Therefore, the first part of this study is dedicated to the electrospinning of poly-epsilon-caprolactone (PCL) nanofibers, the second part focuses on a nm-thick surface chemical modification via a medium pressure non-thermal plasma treatment and the third part investigates the sterilization effects on the surface of the plasma-treated nanofibers. The surface physico-chemical properties are characterized by 3 techniques: scanning electron microscopy (SEM), water contact angle (WCA) goniometry and X-ray photoelectron spectroscopy (XPS). In addition, the cellular performance is evaluated by studying the adhesion and proliferation of adipose-derived stem cells on the samples. The results reveal that argon and air plasmas enhance nanofiber wettability by grafting oxygen-containing functionalities onto the surface. At extended treatment times, argon plasma causes mild morphological alterations, while air plasma provokes pronounced damage, even in short treatment times. In the next step, undamaged plasma-modified fibers are subjected to ethylene oxide (EtO), H2O2 plasma (HP) and UV sterilization techniques. Regardless of the sterilization method, better cytocompatibility is detected on plasma-treated nanofibers compared to untreated nanofibers. EtO increases the WCA and changes the morphology of the plasma-treated samples; these changes are mainly due to the reactions between EtO molecules and the grafted functional groups. HP provokes a total loss of the fibrillary architecture because of the complex thermo-oxidative reactions that occur during the process. UV does not affect the physico-chemical properties of the plasma-modified nanofibers, and UV-sterilized samples show a significantly higher cellular proliferation rate compared to EtO- and HP-sterilized samples. Overall, it can be concluded that plasma-treated nanofibers should be sterilized by UV to maintain their beneficial surface properties induced by non-thermal plasma.

Biofilm-induced changes to the composite surface

ObjectivesComposites may undergo biodegradation in the oral cavity. The objective was to investigate the effect of single- and multi-species biofilms on the surface roughness and topography of two composites. MethodsDisk-shaped specimens of a paste-like, Bis-GMA-free (Gradia Direct Anterior, GC), and a flowable, Bis-GMA-based composite (Tetric EvoFlow, Ivoclar-Vivadent) were prepared. After ethylene-oxide sterilization (38°C), specimens (n=3) were incubated with Streptococcus mutans or mixed bacterial culture (Streptococcus mutans, Streptococcus sanguinis, Actinomyces naeslundii and Fusobacterium nucleatum). As negative controls, unexposed specimens and specimens exposed to sterile medium (BHI) were used. Specimens exposed to acidified BHI medium (pH=5) and enzymatic solution of cholesterol esterase served as positive control. Following 6-week incubation, the attached biofilms were collected for real-time PCR assessment, after which the surface roughness and topography of the specimens were analyzed with atomic force microscopy. Surface hydrophilicity/hydrophobicity was determined by contact angle measurements. Biofilm structure was analyzed with scanning electron microscopy. ResultsEven though multi-species biofilms were thicker, with more cells attached, they did not significantly affect the surface roughness of the composites. On the other hand, S. mutans alone significantly increased the roughness of Tetric by 40.3%, while its effect on Gradia was lower (12%). The total amount of attached bacteria, however, did not differ between the composites. ConclusionsS. mutans can increase the surface roughness of composites, depending on their composition. This ability of S. mutans is, however, mitigated in co-culture with other species. In particular, bacterial esterases seem to be responsible for the increased composite surface roughness upon biofilms exposure. Clinical significanceCariogenic bacteria can degrade composites, thereby increasing the surface roughness. Increased roughness and subsequent improved bacterial accumulation may facilitate the development of secondary caries around composites, which is the most common reason for the restoration failure.

Comparative study in the effects of two different cleaning methods combined with hypothermia sterilization for rigid endoscopic instruments

Objective To investigate the effects of different cleaning methods combined with hypothermia sterilization for rigid endoscopic instruments. Methods A total of 300 thoracoscopes, 60 mediastinoscopes and 200 titanic clips were selected in the supply room of Nanjing Chest Hospital from March to September 2015 and randomly divided into two groups. The control group underwent traditional hand-washing combined with hypothermia sterilization, while the observation group underwent enzymatic ultrasonic cleaning combined with hypothermia sterilization. The cleaning effects of two groups were compared using three different methods: visual method, protein clean & testing stick, and pharynx swab culture. Results All the endoscopic instruments in the observation group has a higher qualified rate than those in the control group, with statistically significant differences between two groups (P<0.05) . Both groups have a qualified rate of 100%. Conclusions The enzymatic ultrasonic cleaning combined with ethylene oxide or hydrogen peroxide hypothermia sterilization for endoscopic instruments guarantes the quality of cleaning and sterilization and is worthy to be promoted. Key words: Hypothermia; Sterilization; Endoscopic instruments; Cleaning

OCCUPATIONAL EXPOSURE AND WORK PRACTICES AMONG ETHYLENE OXIDE STERILIZATION WORKERS

Introduction: Ethylene Oxide (EtO) is a colorless flammable, gas or liquid. In the health care setting, EtO is commonly used for sterilizing heat- and moisture-sensitive medical equipment to prevent health-care associated infections. Aim of work: To assess the Ethylene Oxide (EtO) occupational exposure and work practices among the EtO sterilization workers. Materials and methods: This study included 28 hospital EtO sterilization workers and 32 controls, all of them filled self-administered questionnaire including questions on their demographic characteristics, work experience, and associated symptoms with special attention to pulmonary, digestive, neurologic, hematologic, reproductive, dermatologic and ophthalmologic symptoms. Liver, kidney and ventilatory function tests were carried out for all participants. Work practices of the EtO sterilization workers were assessed. Moreover, EtO 8-hour time weighted average (TWA) and short term 15 minutes personal monitoring were measured. Results: Both 8- hour TWA and short term 15 minutes personal monitoring of the EtO sterilization workers were below the OSHA recommended EtO levels and proper work practices were followed by the workers but 30% of them were not fit tested for respirators use. The study revealed insignificant difference between the EtO sterilization workers and the controls concerning clinical symptoms, liver, kidney and ventilatory function tests. However, the mean of the white blood cells and the lymphocytes absolute numbers were higher among EtO sterilization workers compared to that of the controls, but within the normal range. Conclusion: Routine monitoring of EtO sterilizers; training, proper work practices and periodic medical evaluation of the EtO sterilization workers are important preventive measures to protect them from the harmful effects of EtO. Further research is recommended to study the health effects of EtO exposure at levels below the OSHA 8-hour TWA for EtO