Battelle Team 

Dose Reconstruction 

Project for NIOSH

Document Title: 

Site Profiles for Atomic Weapons Employers that 

Worked Uranium and Thorium Metals 

Appendix CU – Mitts & Merrel Co. 

Document Number: Battelle-TBD-6000 

Appendix CU

Revision: 0 

Effective Date: 7/31/2007 

Type of Document: TBD Appendix

Supersedes: None 

Subject Experts: R.I. Scherpelz, J.D. Catalano 

Document Owner 

Approval: Signature on file Approval Date: 6/28/2007 

Robert I. Scherpelz, Staff Scientist 

Approval Signature on file Approval Date: 6/28/2007 

Jay A. MacLellan, Battelle PNWD Task Manager 

Concurrence: Signature on file Concurrence Date: 6/28/2007 

Richard J. Traub, Staff Scientist 

Approval: Signature on file Approval Date: 7/23/2007 

James W. Neton, Associate Director of Science 

 New Total Rewrite Revision Page Change 

FOR DOCUMENTS MARKED AS A TOTAL REWRITE, REVISION, OR PAGE CHANGE, REPLACE THE PRIOR 

REVISION AND DISCARD / DESTROY ALL COPIES OF THE PRIOR REVISION. 
Document No. Battelle-TBD-6000; 

Appendix CU 

Revision No. 0 Effective Date: 7/31/2007 Page 2 

Mitts & Merrel Company 

CU.1 Introduction 

This document serves as an appendix to Battelle-TBD-6000, Site Profiles for Atomic 

Weapons Employers that Worked Uranium and Thorium Metals. This appendix 

describes the results of document research specific to this site, the Mitts & Merrel 

Company of Saginaw, Michigan. Where specific information is lacking, research into 

similar facilities described in the body of this Site Profile is used. 

CU.2 Site Description 

In 1956, the Mitts and Merrell Company conducted a test for National Lead of Ohio 

(Fernald) in which two pieces of thorium metal (a small piece and a 10-pound piece) 

were reduced to small particle-sized pieces in its Hog Grinder.1

CU.2.1 Site Activities 

The available documentation indicates that at least 10 pounds of thorium metal (no 

isotope specified) was ground into small particles in a hog grinder. Heavy dusting was 

described and confirmed with breathing zone and general area samples. The work was 

performed (the documentation makes it appear that the work took place on one day, June 

28, 1956) in a building which was reportedly razed in 1960. No decontamination of 

equipment or work area was described. Therefore, assume residual contamination period 

from June 28, 1956 through December 31, 1960. 

CU.2.2 Job Categories 

Table CU.1 assigns Mitts & Merrel Company claimants’ job titles as of the effective date 

of this appendix to the Job Categories listed in Bold Text below. The one claimant was a 

machinist/grinder. With no information found in any of the site documentation, it would 

be favorable to assume the claimant was the operator of the hog grinder involved in the 

test. His exposure is therefore characterized as “plant floor high.”

Plant Floor High (Involved directly in operations) 

Plant Floor Low (Involved in support of operations) 

Supervisor (Assumed to spend some time in the production areas) 

Clerk (Assumed to have minimal exposure) 

Claims forwarded to NIOSH by the Department of Labor after the effective date of this 

appendix will be evaluated during the dose reconstruction process to determine the most 

appropriate of the four Job Categories. 

CU.3 Occupational Medical Dose 

No information regarding occupational medical dose specific to Mitts & Merrel 

Company was found. The claimant indicated annual medical x-rays during the 1970’s in 

his CATI interview. Nevertheless, information to be used in dose reconstructions for 

which no specific information is available is provided in ORAUT-OTIB-0006, the dose 

reconstruction project technical information bulletin covering diagnostic x-ray 

procedures. 
Document No. Battelle-TBD-6000; 

Appendix CU 

Revision No. 0 Effective Date: 7/31/2007 Page 3 

CU.4 Occupational Internal Dose 

Based upon all documentation in the file, it appears that AWE work at this facility 

consisted of a one-day test in which two pieces of thorium (a small piece and a 10-pound 

piece) were placed into a hog grinder and reduced to small thorium particles. Air 

sampling was performed during and for a few minutes after the test. The breathing zone 

(BZ) samples cover 1.75 minutes and the general area (GA) samples cover 19 minutes. 

To calculate a daily weighted average (DWA) exposure, a weighted average of the BZ 

samples and another weighted average of the GA samples was used. Since only 20.75 

minutes were covered by the sampling, we assumed dust levels during the period that was 

not sampled to be 50% of the lowest GA sample result or 87 dpm/m3

. The calculated 

DWA is 262.1 dpm/m3

 for the day of the test. A lognormal distribution using this value 

as the mean and a geometric standard deviation of 3 would have a geometric mean of 143 

dpm/m3

. This represents “plant floor high” exposure levels. Assume one full day of 

exposure at this level for all employees on staff on June 28, 1956, the day of the test. 

Other job categories should be scaled as follows: 

• Plant floor low—50% of plant floor high exposure 

• Supervisor—25% of plant floor high exposure 

• Clerical—10% of supervisor exposure (2.5% of plant floor high) 

Tables CU.2 and CU.3 contain inhalation and ingestion intakes. For the operational 

period, the intakes are expressed in terms of pCi for the whole exposure period, for each 

job category and each year. For the residual periods, intakes are expressed as pCi/d 

averaged over a 365-day year. 

CU.5 Occupational External Dose 

There was no information in the site research database with respect to external exposures. 

No radiation surveys were performed during the tests. 

Given the lack of contemporaneous survey data, external doses are calculated based on 

airborne contamination levels as described above. This Battelle TBD provides guidance 

for calculating external doses associated with submersion and surface loading based on 

airborne contamination levels. 

Another source of external dose would be the handling of thorium metal. Assume storage 

of approximately 10 pounds on site for 2 days (this includes the two pieces prior to 

grinding) and the small particle-size pieces after grinding. Also assume the grinder 

handled the two pieces for a total of approximately 2 minutes during the tests and 

packaged the smaller pieces afterward. 

Tables CU.4 and CU.5 contain external doses, associated with the work at this facility. 

For the operational period, the doses are expressed as total dose received during the 

operating day. For residual periods, the doses are expressed as mR/d averaged over a 

365-day year. 

CU.6 Residual Contamination 

The NIOSH “Report on Residual Radioactive and Beryllium Contamination at Atomic 

Weapons Employer Facilities and Beryllium Vender Facilities” indicates that: “Without 

further documentation of follow-up decontamination actions taken at that time, and 
Document No. Battelle-TBD-6000; 

Appendix CU 

Revision No. 0 Effective Date: 7/31/2007 Page 4 

consideration of the assumption that no additional post-operations radiological survey 

documentation exists, it is determined that there is a significant potential for residual 

contamination after completion of this operation. The facility where this work was 

reportedly performed was referred to as the ‘north’ or ‘riverside’ facility. Based on an 

interview with a knowledgeable employee, this facility was demolished in 1959-1960 and 

replaced with a parking lot.2 We assume the facility was demolished at the end of 1960 

and employees were therefore potentially exposed to residual contamination from June 

28, 1960 through December 31, 1960.” 

CU.7 References 

1. DOE Office of Health, Safety and Security, EEOICPA web site. 

http://www.hss.energy.gov/healthsafety/fwsp/advocacy/faclist/findfacility.cfm 

2. Report on Residual Radioactive and Beryllium Contamination at Atomic Weapons 

Employer Facilities and Beryllium Vender Facilities. 

http://www.cdc.gov/niosh/ocas/pdfs/tbd/rescon/rcontam1206.pdf 

http://www.cdc.gov/niosh/ocas/pdfs/tbd/rescon/appen-a2.pdf
Document No. Battelle-TBD-6000; 

Appendix CU 

Revision No. 0 Effective Date: 7/31/2007 Page 5 

Table CU.1Job Categories for all current claimants who worked at Mitts & Merrel Co. 

Job Title Exposure Category 

Machinist/Grinder 1 

. 
Document No. Battelle-TBD-6000; Appendix CU Revision No. 0 Effective Date: 7/31/2007 

Table CU.2 INTERNAL DOSE PATHWAYS - Inhalation of Airborne Radionuclides Assumptions: Operational Period Daily Weighted Average Air Concentration, Plant Floor High: 143 dpm/m3

Residual Period Daily Weighted Average Air Concentration: 0.004 dpm/m3

GSD derived from measurement data Conversion Factor: 2.22 dpm/pCi Breathing Rate: 1.2 m3/hour 

All intakes during the operational period are in total pCi for the operating period. For residual periods, it is pCi/d averaged 

Intake values are the geometric mean of a lognormal distribution 

Job Category Year 

Operation 

Phase Hr/Yr 

Relevant 

Nuclide 

Intake 

(pCi/d*) GSD TBD Reference or Research Ju

Plant Floor High 1956 Operations 10 Th 7.75E+02 3.0 Measured air samples Plant Floor High 1956 Residual 1000 Th 5.73E-03 3.0 

Based on calculated deposition & resuoperation 

Plant Floor High 1957-60 Residual 2000 Th 1.15E-02 3.0 

Based on calculated deposition & resuoperation 

Plant Floor Low 1956 Operations 10 Th 3.87E+02 3.0 Measured air samples Plant Floor Low 1956 Residual 1000 Th 5.73E-03 3.0 

Based on calculated deposition & resuoperation 

Plant Floor Low 1957-60 Residual 2000 Th 1.15E-02 3.0 

Based on calculated deposition & resuoperation 

Supervisor 1956 Operations 10 Th 1.94E+02 3.0 Measured air samples Supervisor 1956 Residual 1000 Th 5.73E-03 3.0 

Based on calculated deposition & resuoperation 

Supervisor 1957-60 Residual 2000 Th 1.15E-02 3.0 

Based on calculated deposition & resuoperation 

Clerical 1956 Operations 10 Th 1.94E+01 3.0 Measured air samples Clerical 1956 Residual 1000 Th 5.73E-03 3.0 

Based on calculated deposition & resuoperation 

Clerical 1957-60 Residual 2000 Th 1.15E-02 3.0 

Based on calculated deposition & resuoperation 
Document No. Battelle-TBD-6000; Appendix CU Revision No. 0 Effective Date: 7/31/2007 

Table CU.3 INTERNAL DOSE PATHWAYS - Ingestion of Airborne Radionuclides Assumptions: Air Concentration to Intake Conversion Factor: 3.06E-05 (M^3/d)/(hr/y) - see 7.1.6 TBD-6000 Deposition velocity: 0.00075 m/s 

 Resuspension Factor: 1.00E-06 1/m

All intakes during the operational period are in total pCi for the operating period. For residual periods, it is pCi/d averaged 

Intake values are the geometric mean of a lognormal distribution 

Job Category Year 

Operation 

Phase Hr/Yr 

Relevant 

Nuclide 

Intake 

(pCi/d*) GSD TBD Reference or Research Ju

Plant Floor High 1956 Operations 10 Th 1.98E-02 3.0 Measured air samples Plant Floor High 1956 Residual 1000 Th 5.34E-05 3.0 

Based on calculated deposition & resuoperation 

Plant Floor High 1957-60 Residual 2000 Th 1.07E-04 3.0 

Based on calculated deposition & resuoperation 

Plant Floor Low 1956 Operations 10 Th 9.89E-03 3.0 Measured air samples Plant Floor Low 1956 Residual 1000 Th 5.34E-05 3.0 

Based on calculated deposition & resuoperation 

Plant Floor Low 1957-60 Residual 2000 Th 1.07E-04 3.0 

Based on calculated deposition & resuoperation 

Supervisor 1956 Operations 10 Th 4.94E-03 3.0 Measured air samples Supervisor 1956 Residual 1000 Th 5.34E-05 3.0 

Based on calculated deposition & resuoperation 

Supervisor 1957-60 Residual 2000 Th 1.07E-04 3.0 

Based on calculated deposition & resuoperation 

Clerical 1956 Operations 10 Th 4.94E-04 3.0 Measured air samples Clerical 1956 Residual 1000 Th 5.34E-05 3.0 

Based on calculated deposition & resuoperation 

Clerical 1957-60 Residual 2000 Th 1.07E-04 3.0 

Based on calculated deposition & resuoperation 
Document No. Battelle-TBD-6000; Appendix CU Revision No. 0 Effective Date: 7/31/2007 

Table CU.4 EXTERNAL DOSE PATHWAYS - Whole Body Assumptions: Submersion Dose Conversion Factor: 2.462E-09 mrem/h/dpm/m^3 Deposition velocity: 0.00075 m/s Contaminated Surface Dose Conversion Factor: 5.615E-10 mrem/h/dpm/m^2 All external dose from estimated exposure to Thorium slugs Residual period: Assume no handling of Th metal - only exposure is from residual contamination on floor and in air All doses during the operational period are in total mR for the operating period. For residual periods, it is mR/d averaged o

Job Category Year 

Operation 

Phase Hr/Yr 

Relevant 

Nuclide 

External 

Whole 

Body 

(mR/d*) GSD TBD Reference or Research Ju

Plant Floor High 1956 Operations 10 Th 1.40E+01 3.0 Generic Metal TBD, Section 6.3 Plant Floor High 1956 Residual 1000 Th 2.37E-07 3.0 Generic Metal TBD, Section 6.3 Plant Floor High 1957-60 Residual 2000 Th 9.49E-07 3.0 Generic Metal TBD, Section 6.3 Plant Floor Low 1956 Operations 10 Th 7.00E+00 3.0 Generic Metal TBD, Section 6.3 Plant Floor Low 1956 Residual 1000 Th 2.37E-07 3.0 Generic Metal TBD, Section 6.3 Plant Floor Low 1957-60 Residual 2000 Th 9.49E-07 3.0 Generic Metal TBD, Section 6.3 Supervisor 1956 Operations 10 Th 7.00E-01 3.0 Generic Metal TBD, Section 6.3 Supervisor 1956 Residual 1000 Th 2.37E-07 3.0 Generic Metal TBD, Section 6.3 Supervisor 1957-60 Residual 2000 Th 9.49E-07 3.0 Generic Metal TBD, Section 6.3 Clerical 1956 Operations 10 Th 3.60E-05 3.0 Generic Metal TBD, Section 6.3 Clerical 1956 Residual 1000 Th 2.37E-07 3.0 Generic Metal TBD, Section 6.3 Clerical 1957-60 Residual 2000 Th 9.49E-07 3.0 Generic Metal TBD, Section 6.3 
Document No. Battelle-TBD-6000; Appendix CU Revision No. 0 Effective Date: 7/31/2007 

Table CU.5 EXTERNAL DOSE PATHWAYS - Skin 

Assumptions: All assumptions from TBD-6000 Section 6.3 Operational Period: Non-penetrating dose to skin 230 mR/hour (hands and forearms) 20.8 mR/hour (other) 

Plant Floor High: Assume hands in contact with metal 50% of time. Other skin is 100% of dose rate at 1-ft, 20

Plant Floor Low: 50% of Plant Floor High 

Supervisor: assume 10% of Plant Floor Low for time in contact with metal Clerical: assume no handling of Th metal. 

Residual Period: Non-penetrating dose to skin 3.9E-06 mr/hour  Assume no handling of Th metal.  Assume 10x the photon whole body dose rate All doses during the operational period are in total mR for the operating period. For residual periods, it is mR/d averaged 

Job Category Year 

Operation 

Phase Hr/Yr 

Relevant 

Nuclide 

Hands & 

Forearms 

(mR/d*) 

Other Skin 

(mR/d*) GSD TBD Reference o

Plant Floor High 1956 Operations 10 Th 1.41E+02 7.00E+01 5 Generic Metal TBD, SectioPlant Floor High 1956 Residual 1000 Th 2.37E-06 2.37E-06 5 Generic Metal TBD, SectioPlant Floor High 1957-60 Residual 2000 Th 9.49E-06 9.49E-06 5 Generic Metal TBD, SectioPlant Floor Low 1956 Operations 10 Th 7.03E+01 3.50E+01 5 Generic Metal TBD, SectioPlant Floor Low 1956 Residual 1000 Th 2.37E-06 2.37E-06 5 Generic Metal TBD, SectioPlant Floor Low 1957-60 Residual 2000 Th 9.49E-06 9.49E-06 5 Generic Metal TBD, SectioSupervisor 1956 Operations 10 Th 7.03E+00 3.50E+00 5 Generic Metal TBD, SectioSupervisor 1956 Residual 1000 Th 2.37E-06 2.37E-06 5 Generic Metal TBD, SectioSupervisor 1957-60 Residual 2000 Th 9.49E-06 9.49E-06 5 Generic Metal TBD, SectioClerical 1956 Operations 10 Th 0.00E+00 0.00E+00 5 Generic Metal TBD, SectioClerical 1956 Residual 1000 Th 2.37E-06 2.37E-06 5 Generic Metal TBD, SectioClerical 1957-60 Residual 2000 Th 9.49E-06 9.49E-06 5 Generic Metal TBD, Sectio