Human skin reaction to ethylene oxide.

Many materials now used in hospitals are sterilized with EO. EO gas retained in porous materials, which have not been properly aired, can produce skin irritation. The experiments reported here were designed to determine the level of EO and duration of skin contact required to produce adverse effects. The role of EO by-products in such reactions was also investigated. To obtain this information, patches retaining EO or its by-products, EC and EG, were applied to the backs of human volunteers. The patches were removed at intervals between 1 and 8 hr and the reactions were observed. The resulting skin reactions directly related to the total dose of EO received. Patch materials that rapidly lose EO, such as fabric or rubber, produced few reactions, even at EO levels as high as 5000 ppm. A patch material that loses EO more slowly, PVC film, produced reactions at EO levels above 1700 ppm. The patch materials that retained EO the longest, thick PVC blocks and petrolatum applied to Webril pads, produced the most reactions. When the EO level in those materials approximated 1000 ppm or higher, skin reactions usually appeared after 4 to 8 hr contact. The level of reactivity among the volunteers was quite consistent. One subject, however, who developed sensitivity to EO, showed a mild delayed reaction to approximately 100 ppm of EO in PVC. The characteristics of that sensitivity are discussed. Since little or no reactions developed to the patches containing EO by-products, EO itself can be assumed to be the toxic agent. The experiments support the conclusion that the lowest level of EO which produces skin irritation in nonsensitized subjects approximates 1000 ppm, when retained in slow-airing material against the skin for 4 hr or more.