Evaluating OSHA's ethylene oxide standard: exposure determinants in Massachusetts hospitals

Emission characteristics of plastic syringes sterilized with ethylene oxide--a controlled study

OBJECTIVES

This study examined the emission characteristics of ethylene oxide (EO)-sterilized syringes under various environmental conditions, aiming to develop control strategies to minimize worker exposure.

METHODS

Experiments were performed in a facility in which temperature, relative humidity (RH), and air change rate (ACR) were controlled.

RESULTS

Analytical results indicate that the main effects of the four test variables on kinetic parameters were statistically significant (p < 0.05), except for the effect of the product on the decay rate constant, the effect of ACR on maximum EO concentration, and effect of RH on the area under the curve-days 1 and 2. The interactive effects among test variables were also evident, indicating complex emission behaviors. The mean EO emission factors during the days 1 and 2 and at the 48th hour for the 1- and 30-ml products were 2302, 1301, and 1031 mg/m(3)/h, and 871, 490, and 381 mg/m(3)/h, respectively. The times required for air EO concentrations from tested products to return to approximately 0 and 1 ppm (permissible limit) were 417 and 218 h, respectively.

CONCLUSIONS

Plastic content, temperature, RH, and ACR affected EO emissions. ACR is an achievable means of control; however, the aeration area/system should be isolated to ensure adequate ventilation is achieved.

Ethylene oxide sterilization in the medical-supply manufacturing industry: assessment and control of worker exposure

OBJECTIVE

In 2005, the Taiwan Institute of Occupational Safety and Health started an on-site consulting program for the medical supplies manufacturing industry, which use ethylene oxide (EO) as a sterilant, with the goal of enhancing occupational hygiene practices and controlling EO-related risks. This study presents EO exposure assessment results and examines the effectiveness of control measures.

METHODS

Detailed surveys, including exposure monitoring, were conducted at 10 factories. Airborne EO was collected using an HBr-coated charcoal tube and analyzed using GC/MS.

RESULTS

Sterilizer operators had an average short-term EO exposure level of 27.61 ppm during unloading; mean time-weighted average workshift exposure was 7.35 ppm. High EO concentrations were also present throughout the facilities. Specifically, mean EO concentrations in the aeration area, near the sterilizer and in the warehouse were 10.19, 5.75, and 8.78 ppm, respectively. These findings indicate that immediate controls are needed, and that EO emissions from sterilized products during storage cannot be overlooked. Worker short-term exposures during unloading was inversely correlated (p < 0.05) with the numbers of poststerilization purge cycle applied. The specific controls implemented and their usefulness is discussed.

CONCLUSION

Increasing the number of poststerilization purge cycles is a simple approach to eliminating extremely high exposure during unloading. Improvements to ventilation, particularly in the aeration area and warehouse, were also effective in minimizing worker exposures. Use of effective respirator is recommended until the EO exposure levels, averaging 3.41 ppm after the controls, fall below the permissible exposure limit.

Ethylene oxide gas sterilization: a simple technique for storing explanted skull bone. Technical note

The authors evaluated the effectiveness of a simple technique using ethylene oxide (EtO) gas sterilization and room temperature storage of autologous bone grafts for reconstructive cranioplasty following decompressive craniectomy. The authors retrospectively analyzed data in 103 consecutive patients who underwent cranioplasty following decompressive craniectomy for any cause at the University of Illinois at Chicago between 1999 and 2005. Patients with a pre-existing intracranial infection prior to craniectomy or lost to follow-up before reconstruction were excluded. Autologous bone grafts were cleansed of soft tissue, hermetically sealed in sterilization pouches for EtO gas sterilization, and stored at room temperature until reconstructive cranioplasty was performed. Cranioplasties were performed an average of 4 months after decompressive craniectomy, and the follow-up after reconstruction averaged 14 months. Excellent aesthetic and functional results after single-stage reconstruction were achieved in 95 patients (92.2%) as confirmed on computed tomography. An infection of the bone flap occurred in eight patients (7.8%), and the skull defects were eventually reconstructed using polymethylmethacrylate with satisfactory results. The mean preservation interval was 3.8 months in patients with uninfected flaps and 6.4 months in those with infected flaps (p = 0.02). A preservation time beyond 10 months was associated with a significantly increased risk of flap infection postcranioplasty (odds ratio [OR] 10.8, p = 0.02). Additionally, patients who had undergone multiple craniotomies demonstrated a trend toward increased infection rates (OR 3.0, p = 0.13). Data in this analysis support the effectiveness of this method, which can be performed at any institution that provides EtO gas sterilization services. The findings also suggest that bone flaps preserved beyond 10 months using this technique should be discarded or resterilized prior to reconstruction.

Exposure to ethylene oxide in hospitals: biological monitoring and influence of glutathione S-transferase and epoxide hydrolase polymorphisms

Ethylene oxide is considered as a human carcinogen. A biomarker of exposure would be a useful instrument to assess the risk in occupationally exposed workers. This cross-sectional study aimed at examining (a) whether the urinary excretion of a metabolite of ethylene oxide, 2-hydroxyethyl mercapturic acid (HEMA), could be used for monitoring occupational exposure and (b) whether glutathione S-transferase (GST) and epoxide hydrolase genotypes influenced biological monitoring. Exposure to ethylene oxide was measured by personal sampling in 80 hospital workers (95% of those eligible). HEMA concentrations were determined in three urine samples (baseline, end of shift, and next morning) by liquid chromatography with tandem mass spectrometry. GSTs (GSTT1, GSTM1, and GSTP1) and epoxide hydrolase (EPHX1) were also genotyped. The influence of exposure, genotypes, and several other factors was examined in multiple regression analyses. Exposure was always <1 parts per million. On a group basis, exposure and a non-null GSTT1 genotype increased the HEMA concentrations in the urine sample collected at the end of the shift and these factors remained statistically significant after considering possible confounding or modifying factors.

Long-term ethylene oxide exposure trends in US hospitals: relationship with OSHA regulatory and enforcement actions

OBJECTIVES

We assessed long-term trends in ethylene oxide (EtO) worker exposures for the purposes of exposure surveillance and evaluation of the impacts of the Occupational Safety and Health Administration (OSHA) 1984 and 1988 EtO standards.

METHODS

We obtained exposure data from a large commercial vendor and processor of EtO passive dosimeters. Personal samples (87,582 workshift [8-hr] and 46,097 short-term [15-min] samples) from 2265 US hospitals were analyzed for time trends from 1984 through 2001 and compared with OSHA enforcement data.

RESULTS

Exposures declined steadily for the first several years after the OSHA standards were set. Workshift exposures continued to taper off and have remained low and constant through 2001. However, since 1996, the probability of exceeding the short-term excursion limit has increased. This trend coincides with a decline in enforcement of the EtO standard.

CONCLUSIONS

Results indicate the need for renewed intervention efforts to preserve gains made following the passage and implementation of the 1984 and 1988 EtO standards.

Occupational risk in health care and research

BACKGROUND

Working in the health care and research sectors has been linked to various hazards.

METHODS

Studies published in the peer-reviewed literature that are pertinent to the exposures or diseases relevant to these fields were reviewed.

RESULTS

The most important exposures include infectious agents, formaldehyde, anesthetic agents, antineoplastic drugs, and ethylene oxide. The best-documented evidence is that of infectious risk primarily among clinical personnel. Monitoring studies of persons occupationally exposed to anesthetics clearly demonstrate behavioral effects, possible risk of reproductive problems, as well as cytogenetic effects of unknown significance. The latter two impairments are also observed among those exposed to antineoplastic drugs and ethylene oxide. Exposure to formaldehyde appears to be associated with nasopharyngeal tumors. Whereas increased risk of cancer of certain sites, particularly the brain and lymphohematopoietic system, is found among research and health care personnel, no specific exposure has been linked to these neoplasms.

CONCLUSIONS

Although some results are inconsistent, continued environmental and biological monitoring will allow better assessment of exposures and of implemented protection measures.

The intervention research process in occupational safety and health: an overview from the National Occupational Research Agenda Intervention Effectiveness Research team

The goal of occupational safety and health intervention effectiveness research is to determine whether specific interventions work to prevent work-related injury and illness. But that is not the whole story. It is also important that the development and implementation of the intervention be evaluated. All three phases (development, implementation, and effectiveness) are central to a model of intervention research proposed by the National Occupational Research Agenda Intervention Effectiveness Research team. Areas for future research are also presented.