An Evaluation of Safety Training for a Diverse Disaster Response Workforce: The Case of the Deepwater Horizon Oil Spill

(1) Background: In this case study, we examined the safety-training-related experiences of individuals from six racial-ethnic groups (Asians (Vietnamese), Blacks, Hispanics, Isleños, Native Americans, and Whites) involved in the cleanup of the Deepwater Horizon oil spill. (2) Methods: We assessed, via a survey, 495 disaster response trainees’ reactions to the design and delivery of training, learning, safety performance, and injury and illness experience. (3) Results: Our results showed statistically significant racial-ethnic group differences with respect to reactions to training, components of learning (i.e., cognitive, skill, and affective), and safety performance (i.e., use of personal protective equipment, engaging in safe work practices, communicating of safety information, and exercising employee rights and responsibilities). In general, Asians and Isleños group members had lower reactions to training, self-reported learning, and safety performance. Additionally, we found that the safety climate interacted with learning to positively affect safety performance. (4) Conclusions: We discuss the implications of our findings for improving the quality of safety training in relation to addressing language and literacy concerns, developing training that is useful and engaging for volunteer and other cleanup workers from the contaminated region, and promoting a positive safety climate to enhance training transfer.

Prognostic analysis of mortality in the cohort of the Chernobyl cleanup workers

Purpose: Analysis and prognosis of mortality rate, specific causes of death and mortality structure in the male cohort of the Chernobyl cleanup workers monitored from 1992 over 2017. Materials and methods: Analysis and prognosis of mortality among the Chernobyl cleanup workers for the follow up period 1992-2017 were based on personal death records stored at the National Radiation Epidemiological Registry (NRER). The workers entered the exclusion zone in 1986 and in 1987, who had documented dose records were included in the monitoring cohort. In 1992 the cohort size was 72432 persons , average radiation dose was 130.8 mGy. For the period of the cohort monitoring 27051 cleanup workers died with the following causes of death: malignant neoplasms – 4621 cases, circulatory diseases – 11410 cases, traumas and poisoning – 5110 cases, other –5910. To prognose mortality and mortality structure data on age-specific intensity of partial mortality and total mortality during the monitoring period were used. Results: The predicted size of the cohort will be 22,000 persons in 2030. Mortality structure in 2017: malignant neoplasms – 17%; circulatory diseases – 42%; traumas and poisoning – 19%, other – 22%. The mortality structure in 2030 will be: malignant neoplasms – 24%; circulatory diseases – 49%; traumas and poisoning – 11%, other – 16%. Cleanup workers’ the average time left to live estimated in 2017 was 11.1 years (their average age in 2017 was 62.4 years), it means that their average life expectancy will be 73.5 years. Average life expectancy of Russian males is 70.4 years. Increased life span of the cleanup workers can be due to their good health, social support including regular special medical examination, the effect of the natural selection cannot be excluded as well. Conclusion: Results of the study can serve as example of organization of high effective specialized medical examination of the Chernobyl cleanup workers. The research outcomes will be useful for analysis of mortality among members of a closed population following exposure to hazardous technogeneous factors.

Lack of transgenerational effects of ionizing radiation exposure from the Chernobyl accident

Effects of radiation exposure from the Chernobyl nuclear accident remain a topic of interest. We investigated whether children born to parents employed as cleanup workers or exposed to occupational and environmental ionizing radiation post-accident were born with more germline de novo mutations (DNMs). Whole-genome sequencing of 130 children (born 1987-2002) and their parents did not reveal an increase in the rates, distributions, or types of DNMs versus previous studies. We find no elevation in total DNMs regardless of cumulative preconception gonadal paternal (mean = 365 mGy, range = 0-4,080 mGy) or maternal (mean = 19 mGy, range = 0-550 mGy) exposure to ionizing radiation and conclude over this exposure range, evidence is lacking for a substantial effect on germline DNMs in humans, suggesting minimal impact on health of subsequent generations.

Radiation Exposure to the Thyroid After the Chernobyl Accident

IntroductionThe Chernobyl accident resulted in a considerable release of radioactivity to the atmosphere, particularly of Iodine-131 (131I), with the greatest contamination occurring in Belarus, Ukraine, and western part of Russia.Material and MethodsIncrease in thyroid cancer and other thyroid diseases incidence in population exposed to Chernobyl fallout in these counties was the major health effect of the accident. Therefore, a lot of attention was paid to the thyroid doses, mainly, the 131I intake during two months after the accident. This paper reviews thyroid doses, both the individual for the subjects of radiation epidemiological studies and population-average doses. Exposure to 131I intake and other exposure pathways to population of affected regions and the Chernobyl cleanup workers (liquidators) are considered.ResultsIndividual thyroid doses due to 131I intake varied up to 42 Gy and depended on the age of the person, the region where a person was exposed, and their cow’s milk consumption habits. Population-average thyroid doses among children of youngest age reached up to 0.75 Gy in the most contaminated area, the Gomel Oblast, in Belarus. Intake of 131I was the main pathway of exposure to the thyroid gland; its mean contribution to the thyroid dose in affected regions was more than 90%. The mean thyroid dose from inhalation of 131I for early Chernobyl cleanup workers was estimated to be 0.18 Gy. Individual thyroid doses due to different exposure pathways varied among 1,137 cleanup workers included in the epidemiological studies up to 9 Gy. Uncertainties associated with dose estimates, in terms of mean geometric standard deviation of individual stochastic doses, varied in range from 1.6 for doses based on individual-radiation measurements to 2.6 for “modelled” doses.ConclusionThe 131I was the most radiologically important radionuclide that resulted in radiation exposure to the thyroid gland and cause an increase in the of rate of thyroid cancer and other thyroid diseases in population exposed after the Chernobyl accident.

Prospective lifetime radiation risk of cancer among Russian cleanup workers in Chernobyl

As stated in the Basic sanitary rules of radiation safety, radiation risk is one of the main character-istics of radiation safety. Before the work persons involved in cleanup operations after radiation accidents should be informed about subsequent risks to their health. However, mathematical models for radiation risk prediction and methods for its calculation are currently at the stage of scientific research and have not yet been standardized for solving practical problems of risk pre-diction. At the international level, UNSCEAR, ICRP and WHO developed radiation risk models on the basis of radiation-epidemiological data on survivors of Hiroshima and Nagasaki atomic bombings in August 1945. In recent decades, data on radiation-epidemiological follow-up of co-horts contained people exposed to radiation after the Chernobyl accident in 1986, in particular NRER data, have been used to identify and assess radiation risks. The radiation risk models iden-tified from the Chernobyl cohorts of exposed individuals differ from the models identified from the Japanese cohort, which leads, respectively, to different projections of lifetime radiation risk. The purpose of this work is to compare quantitatively the possible lifetime radiation risks of can-cer for a cohort of Russian liquidators of the Chernobyl accident, evaluated with radiation risk models developed by UNSCEAR, WHO and NRER. It is shown that after 2020, 1297 cases of cancer are expected in the cohort of Russian liquidators, this figure is 2.4 times higher than esti-mates obtained with the international models. The radiation risk model of leukemia, built on the basis of NRER follow-up data, predicts 145 cases of leukemia in the observed cohort of liquida-tors, which is 8 times higher than the values estimated with the use of international models. Since the liquidators of the considered cohort are generally over 50 years old, the results obtained may indicate the need to adjust the dose limits established by the current radiation safety standards based on ICRP risk models for people over 50 years old.

Estimating of radiation risks of malignant neoplasms among Russian Chernobyl cleanup workers

The paper considers radiation risks of solid cancer incidence and mortality, as well as risk of leu-kemia incidence (other than chronic lymphocytic leukemia) among Russian Chernobyl cleanup workers (liquidators). The study of the cohort of liquidators carried out at the National Radiation Epidemiological Registry (NRER) was based on the follow-up data collected from 1992 over 2019. The size of the Chernobyl cleanup workers cohort exceeded 65 thousand people, their av-erage age at the time of entering the exclusion zone was 34 years, the average external gamma radiation dose received by liquidators during their cleanup work was about 0.133 Gy. Radiation-induced risks of solid cancer incidence and mortality in the study cohort were statistically signifi-cant, the risk magnitude rose with increasing the follow-up length. For the maximum follow-up period, from 1992 over 2019, the excess relative risk coefficient for solid cancer incidence was ERR/Gy=0.62, 95% CI (0.29; 0.98), and excess relative risk coefficient for solid cancer mortality was ERR/Gy=0.74, 95% CI (0.32; 1.22), the estimated coefficients were in good agreement with similar coefficients calcu-lated for the Russian liquidators with the use of ICRP radiation risk models. Non-parametric esti-mates of relative radiation risk within the same dose intervals for solid cancers and for leukemias in the cohort of liquidators were statistically significant for radiation doses above 0.150 Gy. For radiation doses below 0,150 Гр the linear non-threshold model is conservative, i.e. there was ev-idence for statistically significant radiation risk of leukemia incidence among liquidators during the first 11 years after the accident, from 1986 over 1997, ERR/Gy=4.41, 95% CI (0.24; 14.23). In later years, until 2018 there was no evidence of radiation-related risk of leukemia incidence. Out-comes of future studies will impact on optimization of radiological protection, development of reference levels for Russian general public exposure and improvement of the system for delivery of targeted medical care to people exposed to radiation.