Kansas City Plant

Special Exposure Cohort Petition 

Evaluation Report

Grady Calhoun, CHP

Supervisory Health Scientist

NIOSH/DCAS

January 28, 2014

Kansas City, Missouri
Overview 

 Received March 12, 2013

 Petitioner requested class definition

• All Bannister Federal Complex employees who worked at the 

Bannister Federal Complex from 1949 to present

 Qualified July 1, 2013

• Basis – Radiation exposures and doses potentially incurred 

by members of the proposed class were not monitored 

either through personal or area monitoring
Overview – continued

 NIOSH-designated Evaluation Report (ER) start date consistent 

with the start of AEC operations 

 Examined 160 claims with employment 1994 or later to 

coincide with KCP’s implementation of 10 CFR 835 to 

determine evaluation period end date 

 NIOSH found no apparent and potentially inadequatelymonitored exposures for post-1993
NIOSH-evaluated class

All employees who worked in any area of the 

Kansas City Plant in Kansas City, MO, from 

January 1, 1949 through December 31, 1993
Background 

 Main Manufacturing Building main structure 

 About 2.7 million square feet of contiguous space 

 Houses the primary KCP manufacturing operations
Background – continued 

 From the start principal operation to make 

non-nuclear components of nuclear weapons

• Machining and fabrication of metals and plastics, plating, 

microelectronics, and electrical and mechanical assembly

 Currently makes about 85% of the non-nuclear 

components for the U.S. atomic stockpile
Background – continued

 Natural uranium work

• Machined uranium slugs, handled uranium billets 

and ingots from February 1951 to December 1952

• Performed this work in the Main Manufacturing 

Building (Department 49X)

• Total of 313,070 lbs machined into slugs 

• Capacity to produce 1,000 slugs per day
Background – continued

 Natural uranium work (cont.)

• Inspected and assembled uranium components 

from May 1950 to February 1955 in the Main 

Manufacturing Building (Department 3A)
Background – continued

 Depleted uranium (DU) work

• April 1958 to about 1971

• Machined and inspected DU products in Department 20

(about 12,000 ft2 of the Main Manufacturing Building)

• Main source of radiological exposure associated with 

machining items that contained DU oxide 

• Program using DU oxide ended in 1972
Background – continued

 Magnesium Thorium alloy (Mg-Th) work

• Supplied by DOW - HK-31 alloy ~3% Thorium

• May 1, 1957 to April 5, 1979 - machined and 

fabricated classified items with Mg-Th alloy in two 

areas of the Main Manufacturing Building 

(Department 20 and the Model Shop)

• Strict operational controls to prevent airborne 

generation
Background – continued

 Thorium oxide (ThO2) powder work

• Reviewed one document that stated from July 23, 1958 to 

July, 1959 was handled in the plant.

• Several personal communications with site experts and 

review of radiological source inventories found that 

handling was limited to small-scale laboratory analysis and 

preparation of solutions used in analytical procedures 
Incidents 

Erbium Tritide (September 30, 1987)

 Worker removed the cover of a W80 Data Analyzer 

and noticed that the interior not decontaminated as 

required, immediately replaced cover

 Surveys performed of the analyzer and the work area

 Contamination only detected on the inside of the 

cover at 986 dpm/100 cm2
Incidents – continued

Erbium Tritide (cont.) 

 Analyzer returned to Sandia National Laboratory for 

decontamination

 Urinalysis performed for the worker who removed the 

cover; results indicated no detectable activity for 

tritium as erbium tritide (sol class M from ICRP 71)

 This was an isolated, one time incident
Incidents – continued

Promethium-147 -February 10, 1989

 100% beta-emitting, EMax 224.7 keV, half-life of 2.6 

years

 Failure of the integrity of one of these sources 

resulted in a spread of contamination to multiple 

areas inside and outside of facility

 97 personnel internally monitored, no internal 

exposures 

 Workers’ homes inspected, one needed 

decontaminated
Sources of Available Information

 Site Profile TBD-6000, used to model internal doses 

for the natural uranium machining operations

 KCP Site Profile ORAUT-TKBS-0031 (2006), used to 

describe DU internal doses and external doses

 Reviewed 1,645 NIOSH Site Research Database 

documents

 Conducted 19 interviews

 Standard data searches conducted
Prior Dose Reconstructions 

NIOSH DCAS Claims Tracking System 

Information available as of November 22, 2013

 KCP claims submitted for dose reconstruction 672 

 Cases submitted for energy employees who 

worked during the period under evaluation

(1/1/49 - 12/31/93) 665 

 Number of dose reconstructions completed 

 for energy employees who worked during the

period under evaluation 608 

 Cases for which internal dosimetry records

were obtained 35

 Claims for which external dosimetry records 

were obtained 103

 

 
Personal Monitoring Data

 Internal Monitoring Data

• Routine bioassay data (urinalysis) available 

for the DU work 1959 - 1971

• Air sample data:

• 1952 dust analysis

• 1958 - 1971 Gross alpha Fixed-filter air 

monitoring in the Main Manufacturing Building 

general area
Personal Monitoring Data – continued

 Internal Monitoring Data (cont.)

• Air sample data:

• Magnesium Thorium (Mg-Th) Operations

• In 1970, KCP evaluated all of their Mg-Th

machining operations in the Model Shop

• The evaluation validated that KCP maintained 

airborne levels in the breathing-zone for longlived activity at background, and short-lived 

activity at <3.22E-9 μCi/ml (gross alpha)
Personal Monitoring Data – continued

 External Monitoring Data

 Access to 13,846 external dosimetry records that 

include monitoring data for deep dose, shallow dose, 

extremity dose (rings) and neutron dose, for the years 

1950 - 1993 

 KCP participated in DOE LAP performance testing 

using Landauer-provided services starting in October 

1992 
Area Monitoring Data

 Recently obtained copies of

• 1959 - 1969 and 1990 - 1993 routine contamination 

and radiation surveys 

• Contamination survey data and volumetric 

sampling data from 1984-1986 Decontamination 

and Decommission (D&D) activities 
Evaluated Period Potential 

Radiation Exposures

 Internal sources of exposure

• Inhalation and ingestion of uranium and thorium by workers 

at KCP

• Residual airborne radioactive contaminants may have been 

present at low levels after the operations ceased

 External sources of exposure

• Photon / beta exposure from the uranium and thorium source 

material, and small amounts of surface contamination that 

was present after operations ceased.

• Sources of neutron radiation involved Karman Model A-800 

pulsed-neutron generators and 239PuBe sources. The first 

presence of neutron-emitting sources occurred after 1965 
Evaluated Period Potential 

Radiation Exposures

 External sources of exposure

• Isotopic (beta, gamma-ray) sources that are 

typically used in manufacturing quality control 

procedures to monitor fabrication processes

• Industrial radiation generating devices (X-rays and 

electron accelerators)
Feasibility of Dose Reconstructions

 Available monitoring records, process 

descriptions, and source-term data are 

adequate to complete DRs with sufficient 

accuracy for evaluated worker class 
Feasibility Approach – continued

 Natural Uranium Operations

• NIOSH is satisfied that TBD-6000 can be 

used to estimate KCP exposures when 

dosimetry is not available
Feasibility Approach – continued

 Natural Uranium Post Operations Period

• Internal exposures after natural U operations ended 

and before DU internal monitoring started

• March 1, 1955 to August 11, 1959

• Use the maximum measured gross alpha air sample 

during this post operations period

• Use TBD-6000 methodology to bound air 

concentrations for worker classes with less 

exposure potential than the machine operators
Feasibility Approach – continued

 Magnesium Thorium Operations

• KCP specified engineered control levels at the 

beginning of operations in 1957 at 9E-11 μCi/ml

• October of 1959 KCP lowered limit to 3E-11 μCi/ml 

• Performed (Gross α) fixed-filter air-monitoring in 

the Main Manufacturing Building (GA) during first 

13 years of these operations

• Maintained operations at 2.85E-12 μCi/ml (Average), 

<8.55E-11 μCi/ml (Maximum)
Feasibility Approach – continued 

 Magnesium Thorium Operations (cont.)

• The initial KCP limit of 9E-11 μCi/ml for Th232 would 

equate to ~27 mg/m3 total-dust air-concentration; not 

well-tolerated for a full shift (W. R. Van Pelt, Bethlehem 

Steel study)

• In 1970, KCP performed worksite, breathing-zone airsampling (Gross α) and validated that their process 

does not generate airborne radioactivity

• This validation was performed prior to KCP’s cessation 

of fixed filter air-monitoring in 1971
Feasibility Approach – continued

 Magnesium Thorium Operations (cont.)

• To bound internal exposures for machine operators, NIOSH will use:

• initial engineered limit of 9E-11 μCi/ml and apply it in a constant manner 

from 5/1/57 through 10/31/59

• lowered engineered limit of 3E-11 μCi/ml and apply it in a constant manner 

from 11/1/59 through 4/30/79

• Ingestion doses derived with OCAS-TIB-009

• Thoron exposure: use highest 1970 short-lived sample, 3.2E-9 μCi/ml 

yields, 5.1 WLM/yr

• TBD-6000 methodology used to bound air concentrations for classes of 

workers with less exposure potential or that spent less time in the 

machining area than the machine operators
Feasibility Approach – continued

 Bounding thorium intakes after Mg-Th operations 

ceased and before facility D&D

• Assume air concentration at the end of 

operations was the lower limit of 3E-11 μCi/ml 

(66.6 dpm/m3) 

• Use deposition, re-suspension and depletion 

models to assign intakes. 

• Ingestion doses derived using OCAS-TIB-009
Feasibility Approach – continued

 Bounding thorium intakes after Mg-Th operations ceased 

and before facility D&D

 Thoron dose basis for this period will start the period at 

5.1 WLM/yr and will use the same depletion rate (4.23 E4/yr) to determine the exposure for each year of this 

period

 TBD-6000 methodology used to bound air concentrations 

for classes of workers with less exposure potential or that 

spent less time in the machining area than the machine 

operators
Feasibility Approach – continued

 Bounding uranium intakes after Mg-Th 

operations ceased and before facility 

D&D

 Maximum measured surface contamination 

survey taken during DU machining 

operations will be used to model a starting 

point air concentration for this postoperational period
Feasibility Approach – continued

 Bounding uranium intakes after Mg-Th

operations ceased and before facility D&D

• Applying a re-suspension factor of 1E-5/m, yields an air 

concentration of 0.6 dpm/m3 (0.27 pCi/ m3) for the end of 

the post operations period on May 31, 1984 

• A depletion rate will be applied to the initial air 

concentration to determine the remaining activity 

available for inhalation and ingestion for machine 

operators during each year of this post operations period
Feasibility Approach – continued

 Bounding uranium intakes after Mg-Th

operations cease and before facility D&D

 TBD-6000 methodology used to bound air 

concentrations for classes of workers with 

less exposure potential or that spent less 

time in the machining area than the 

machine operators
Feasibility Approach – continued

 D&D Activities 6/1/84 – 9/3/86

• Rockwell employees were monitored

• Barriers set-up around work area and continuous 

air monitoring performed outside perimeter

• Monitored for U238 at 1E-12 μCi/ml control level

• Assume KCP employees are exposed at the 

perimeter air-concentration during this period
Summary 

Summary of Feasibility

(January 1, 1949 through December 31, 1993)

Source of Exposure Feasible Not Feasible

External X 

Internal X