Missing annual external radiation dosimetry data among Hanford workers

Area of Science:

• Occupational Health
• Radiation Epidemiology
• Environmental Health

Background:

• Hanford Site epidemiological studies have spanned three decades.
• External radiation dosimetry at Hanford has been comprehensive, but data gaps exist.
• Previous analyses may be affected by missing annual external radiation dosimetry records for some workers.

Purpose of the Study:

• To investigate the extent of missing annual external dosimetry records for Hanford workers.
• To evaluate a "nearby" procedure for estimating missing dosimetry values.
• To assess the impact of missing records on cumulative dose estimations.

Main Methods:

• Utilized employment history and annual external dosimetry records.
• Analyzed data for 33,459 workers employed at least 180 days with dosimetry records.
• Applied a "nearby" procedure to estimate missing annual external dosimetry records.

Main Results:

• 8% of employment years (32,323 records) had missing annual external dosimetry.
• Missing records were more prevalent in female workers and those employed in early operational years.
• The "nearby" procedure estimated 18,937.5 mSv for missing records, representing 2% of the total recorded dose.

Conclusions:

• Missing annual external dosimetry records are a significant issue at the Hanford Site.
• The "nearby" procedure offers reliable estimation for missing dose data.
• Missing records introduce potential bias and uncertainty into radiation-cancer association studies of Hanford workers.