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.


CONCLUSIONS
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.
Chien
Yeh-Chung
YC
Department of Industrial Safety and Health, Hungkuang University, Shalu, Taiwan. yc@sunrise.hk.edu.tw
Liu
Hung-Hsin
HH
Lin
Yi-Chang
YC
Su
Po-Chi
PC
Li
Lien-Hsiung
LH
Chang
Cheng-Ping
CP
Tang
Da-Toung
DT
Chen
Chang-Yuh
CY
D000395:Air Pollutants, Occupational / Q000032:analysis* / Q000633:toxicity; D004784:Environmental Monitoring; D005027:Ethylene Oxide / Q000032:analysis* / Q000633:toxicity; D006801:Humans; D007221:Industry; D019570:Inhalation Exposure / Q000517:prevention & control*; D016273:Occupational Exposure / Q000517:prevention & control*; D013242:Sterilization; D013624:Taiwan
D000395:Air Pollutants, Occupational; D005027:Ethylene Oxide