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Administrative data

Endpoint:
health surveillance data
Type of information:
other: Review
Adequacy of study:
supporting study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Data source

Reference
Reference Type:
publication
Title:
Biological monitoringtoassessdermalexposuretoethyleneoxide vapours duringanincidentalrelease
Author:
Boogaard P. J., Puijvelde M. J. P., Urbanus J. H.
Year:
2014
Bibliographic source:
Toxicology letters 231 (2014) 387-390
Report date:
2014

Materials and methods

Study type:
biological effect monitoring
Endpoint addressed:
basic toxicokinetics
Principles of method if other than guideline:
Estimation of the dermal contribution of exposure to EO vapours under normal operating circumstances and during response to product spillage when operator wear independent breathing apparatus, but no specific full-body dermal protection such as chemical impervious suits.
GLP compliance:
no

Test material

Constituent 1
Chemical structure
Reference substance name:
Ethylene oxide
EC Number:
200-849-9
EC Name:
Ethylene oxide
Cas Number:
75-21-8
Molecular formula:
C2H4O
IUPAC Name:
oxirane
Specific details on test material used for the study:
The report is based on an incident in an ethylene oxide production plant. The purity of the substance during the incidence was not specified in the review.

Method

Type of population:
occupational
Ethical approval:
not applicable
Details on study design:
Three male workers, aged 26, 30 and 42 years, were involved in the repairs following an incidental leak of EO in an EO-manufacturing plant. All three were nonsmokers with no recent exposure to EO. Blood samples were collected ca. 20 h following the incident and hydroxyethylvaline (HEV) was measured as a marker of EO exposure.

Results and discussion

Results:
Using the blood samples from the three exposed operators which had an hydroxyethylvaline (HEV) level of 177.6, 42.8, and 214.2 pmol/globin it was calculated that the exposure during the repairs had been 1.79, 0.23, and 2.21 ppm as 8-h TWA. Two of the three operators have had exposure to EO one to two magnitudes over the Dutch OEL (0.5 ppm), which was almost certainly caused by dermal uptake of EO vapour.

Any other information on results incl. tables

For the first scenario (normal working conditions), both models indicated a small dermal contribution when compared with the dose received via inhalation. The Rauma model claculated a dermal contribution ratio (DCR) of 0.2% and the IndusChemFate a DCR of 1%. Thus, the dermal contribution to systemic EO exposure appears to be negligible in comparison with the contribution of the inhalation route.

In an accidental scenario, the systemic exposure received via inhalation was expected to be 0.02 ppm (8-h TWA). The dermal uptake, claculated with the Rauma model would be 0.06 ppm and the total exposure less than 0.08 (8-h TWA). The IndusChemFate model calculated the exposure to be 0.31 ppm and a total exposure of less than 0.33 ppm (8-h TWA).

Another scenario using the ART programme resulted in a systemic exposure via inhalation of >0.6 ppm. The dermal uptake would be 2.6 ppm (Rauma model) and 12.8 ppm (IndusChemFate) and the total exposure 3.2 ppm and 13.4 ppm (8-h TWA).

Applicant's summary and conclusion

Conclusions:
The results of the calculatons presented here in combination with the actual data from an incidental release of EO, confirm the need to consider the dermal exposure route for accidental scenarios involving EO spillage.
Executive summary:

During a short incident in an ethylene oxide (EO) producing plant, EO vapour was released under high pressure. Operators wore full respiratory protection during repairs tox the leak. To check the adequacy of the applied personal protective equipment and to address concerns about potential dermal exposure and subsequent uptake of EO, biological monitoring was applied by determination of the haemoglobin adducts of EO in blood. Based on the results of the biomonitoring, a risk assessment of dermal exposure to EO vapour was made.

Calculations to estimate dermal exposure, based on two recently published models and using the relevant physical–chemical properties of EO, indicate that the dermal contribution to total exposure is expected to be negligible under normal operating circumstances. However, the models indicate that under accidental circumstances of product spillage, when high air concentrations can build up quickly and where incident response is conducted under respiratory protection with independently supplied air, the systemic exposure resulting from dermal absorption may reach levels of concern.

The model estimates were compared to the actual biomonitoring data in the operators involved in the accidental release of EO vapour. The results suggest that when incidental exposures to high EO vapour concentrations (several thousand ppm) occur during periods in excess of 20–30 min, additional risk man- agement measures, such as wearing chemical impervious suits, should be considered to control dermal

uptake of EO.

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