EH-91-1 Mortality Among Workers Exposed to Ionizing Radiation         
                 OFFICE OF EPIDEMIOLOGY & HEALTH SURVEILLANCE

                            HEALTH BULLETIN

U.S. DEPARTMENT OF ENERGY                             WASHINGTON, D.C.
Issue 91-1                                                  April 1991


The Journal of Occupational Medicine will publish, in the May 1991
issue, a paper entitled "Mortality Among Workers Exposed to External
Ionizing Radiation at a Nuclear Facility in Ohio."  The study was
carried out by Dr. Laurie Wiggs and colleagues at the Los Alamos
National Laboratory under contract to the Department of Energy (DOE).

Using personnel records, the investigators identified 4,182 white male
workers employed between 1947 and 1979 at the Mound Facility, located
near Dayton, Ohio.  The study focused on white men because the
numbers of women and non-whites were small, and the total career
radiation doses among the women were lower than those among the men.

Occupational external radiation exposure information was available for
3,229 of the Mound workers.  In general, the median total career
external radiation dose received by the workers was quite low, about
the amount an average person would receive from natural sources over
a period of 10 years.  Eighty-two percent (82%) of the men had a
recorded total external radiation dose of less than 50 millisieverts
(mSv, 10, mSv = 1 rem), the current annual dose limit.  These
monitored workers were divided into two categories, those who had a
total dose of less than 10 mSv, and those whose total external dose
was higher than 10 mSv.  No differences in death rates were found
between the two groups.

The researchers also compared death rates among 3,229 monitored
white male Mound workers with those for white men in the United
Stated general population who were of similar age.  The Mound workers
had a lower mortality rate from all causes combined than did white
men in the United States general population (304 deaths were
observed among white male Mound workers and 387 were expected). 
Sixty-six deaths from all types of cancer combined were observed and
75 would have been expected based on rates for United States white
men of the same age.

A more detailed analysis was done to determine if the risk of death
increased with increasing external radiation exposure.  No
relationship with dose was seen for all causes of death combined, all
cancers combined, digestive cancers, or lung cancer.  There was an
increase in the risk of leukemia in workers in the "high" radiation
exposure category compared with those in the lowest exposure
category, but this finding was based on only two deaths from leukemia
in the "high" exposure category.  One of these deaths was due to
chronic lymphatic leukemia, which is not generally considered to be
caused by exposure to ionizing radiation.

In general, the Mound workers had lower mortality rates than United
Stated men, a finding supported by data from other studies of DOE
workers.  Recently, an excess of leukemia mortality was reported
among white male DOE workers at the Oak Ridge facility, but this was
not associated with recorded level of occupational radiation exposure.
Additional followup of this and other DOE worker cohorts are necessary
before any conclusions can be drawn regarding the relationship
between leukemia and occupational exposure to radiation or other
materials in DOE facilities.

NOTE:  Another analysis of mortality rates among Mound Facility
workers by date of hire and duration of employment is available in
Los Alamos Report #LA-11997-MS.

                     - Additional Mound Analyses -

The July 1991 issue of Health Physics will publish a separate paper
entitled "Mortality Among a Cohort of Workers Monitored for (210) Po
Exposure:  1944-1972," which presents an analysis of mortality among
4,402 white males who worked at the Mound facility between 1944 and
1972. This was the period during which Polonium-210 was used, and
monitoring was conducted for internal radiation dose.  (Note:  There
was considerable overlap between this study group and the previous
one.  The study periods were slightly different, because of the
availability of recorded exposure estimates; and this group was
followed for mortality through the end of 1983).  Among 2,181 Mound
workers monitored for Polonium-210 exposure, mortality from all causes
of death combined was lower than expected compared with the United
States general population.  The numbers of deaths from specific types
of cancer and other causes were within the expected ranges.  When
mortality was examined by recorded internal dose of Polonium-210, no
relationships with exposure level were noted for all causes combined,
all cancers combined, or any specific type of cancer.



This Health Bulletin is one in a series of routine publications issued
by the Office of Health to share data from health studies throughout
the DOE complex.  For more information contact: Dr. Terry L. Thomas,
Director, Health Coordination and Communication Division, Office of
Epidemiology and Health Surveillance, U. S. Department of Energy,
Washington, DC 20585; Telephone FTS 233-5328, Commercial (301)
353-5328.



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