Nuclear Metals, Inc.

Special Exposure Cohort Petition

Evaluation Report 

Addendum 

Dr. Samuel Glover

NIOSH 

Division of Compensation Analysis and Support

April 29, 2014

Augusta, GA 
Site Overview

 Emerged from Massachusetts Institute of Technology’s (MIT) 

special metallurgical operations for the Manhattan Engineer 

District (later merged into Hood Building on MIT campus)

 Assumed operations control at Hood Building as private 

company (transferred operations in 1958 to Concord, MA)

 Provided Atomic Energy Commission fabrication capabilities 

and metallurgical consulting services (uranium, thorium, 

many alloys of these elements

 Started large-scale depleted uranium (DU) munitions for U.S. 

military

 Covered period – AWE facility October 29, 1958-1990; 

Residual period from 1991-March 1, 2011
Petition Overview

 Petition received October 20, 2011 (83.13)

 Petitioner-proposed class definition 

All employees who worked in Buildings A, B, C, D, E, the 

Butler Building, external storage containers, and outside 

areas immediate to plant grounds at the Nuclear Metals, 

Inc. facility in West Concord, Massachusetts, during the 

period from January 1, 1970 through December 31, 1983
Petition Overview - continued

NIOSH 

proposed class 

addition of all 

workers at 

covered 

facility 

Oct. 29, 1958 

through 

Dec. 31, 1979

Based on 

inability to 

reconstruct 

internal dose 

for Thorium 

and enriched 

Uranium 

 Board agreed, 

recommended 

class addition. 

Class added 

on Jan. 6, 

2013

NIOSH 

reserved 

1980 - 1983 

time period 

to review 

several 

thousand air 

monitoring 

and bioassay 

records from 

that time 

period 

NIOSH 

reviewed 

Jan. 1, 1980 

through 

Dec. 31, 1990 

time period
Sources of Available Information

 ORAU Team Site Profiles and Technical Information 

Bulletins (TIBs) and Procedures

 NIOSH Site Research Database

 Existing claimant files

 Information from petitioner which included 9 

affidavits with 23 supporting documents

 Worker interviews (21) as well as information from 

claimant telephone interview files (CATIs)

 ATL/ORAUT/NIOSH conducted three outreach 

meetings in Concord attended by approximately 50 

former workers and company management (some of 

whom were present from the beginning (at MIT))
Data Capture Efforts 

 Standard database searches 

 Internet 

 Department of Energy (DOE) locations – 

Office of Scientific and Technical Information, Hanford, DOE 

Germantown, Legacy Management, Grand Junction, Morgantown, 

Sandia, Savannah River, Health and Safety Laboratory-Environmental 

Measurements Laboratory (HASL-EML)

 Hagley Museum & Library

 Nuclear Regulatory Commission (NRC)

 Documents from U.S. Environmental Protection Agency, 

Massachusetts Department of Environmental Protection 
Status of Claims

(as of March 27, 2014) 

Total submitted 26 

Claims for those who worked during proposed 

SEC time period 19 

Dose reconstruction 

at Department of Labor (DOL) 18

With dosimetry records External 19 / Internal 19 
Background 

Operated at 

the Hood 

Building (DOE) 

near MIT until 

October 28, 

1958

NMI at Concord, MA 

(evaluated site) was 

located at 2229 Main St. 

on 30 acres, 1990 it 

expanded to 46.4 acres

Began moving 

operations to Concord 

after March 1958 and 

fully transferred 

operations on October 

29, 1958, DOL date for 

Atomic Weapons 

Employer (AWE) facility 

status

Employed 60 to more than 650 workers during the time period 

under review (peaked in early 1980s)
Background – continued

Original facility consisted of three buildings

A Office space and research laboratories (analytical, x-ray equipment, vacuum 

furnaces) 

B Services (cafeteria, electrical switch room, lockers) and sometimes used as 

needed to hold radioactive materials

C Main production facility and included equipment for melting metals, extrusion, 

metal working, pickling and etching, and electroplating 

Additional building added over time

D 1978 - to expand the production space

E 1983 - production area for wet processes (pickling, coolant recovery, waste 

treatment)

BB Butler Buildings (BB) - added over time and used for storage and sometimes 

pressed into service as needed 
Background – continued

Diagram of NMI in 1984
Background – continued

 Partial listing of operations conducted pre-1972

• Fundamental, physical, and chemical metallurgy

• Production element and fuel element development and 

manufacture

• Manufacture of high-temperature materials

 Operations 1972 - 1979

• Shifted to large-scale production (manufacture of depleted 

uranium shields, counter weights, armor penetrators, metal 

powders, beryllium and beryllium alloys, and specialty titanium 

parts 

• Enriched uranium operations discontinued in 1974
Post 1979 operations

 Similar as described for 1972-1979 

• Shifted to large-scale production including the 

manufacture of DU shields, counter weights, armor 

penetrators, metal powders, beryllium and beryllium 

alloys, and specialty titanium parts

 Melting and casting of DU and UF4

• In 1983 UF4 processing ceased and was transferred to 

Carolina Metals, SC

 Billet operations

• Assembly, extrusion, copper, 

removal/pickling/straightening
Post 1979 operations - continued

 Provided depleted uranium and natural 

uranium for AVLIS project at Lawrence 

Livermore National Laboratory 

 Metal powders and materials programs 

included thorium

 Maintained license for millions of pounds of 

DU and up to 25,000 kg of thorium into the 

1990s
Health Physics Program

 No trained health physics staff until 1981

 Program transferred from Hood Building in 1958

 The programs were research in nature and thus the staff 

often unaware of new hazards which may be encountered

 Program evolved over many years, may have periods of 

lapses into poor practices

• Mid-1960s reports describe significant U spills and 

contamination which were left unreported

• Inspection reports from the mid-1970s emphasize lack of 

contamination controls and monitoring
Health Physics Program

 Improvements in the radiation protection program 

coincided with the growth of the company in the late 

1970s and 1980s and emphasis to becoming a production 

program

 Reported improvements were described as

• Access controls enforced

• Increased air monitoring program

• Air and swipe sample analysis brought in-house to reduce delays

• Employee radiation safety training provided by full time training 

specialists as part of orientation

• Increased health physics coverage for all three work shifts

• Large increase in the amount of uranium bioassay samples collected 

• Still in 1980-84, there were 70 documented fires, smoke and spill 

incidents. 

• NIOSH has not located any incident document after 1984
Source of Internal Exposure

 Research and production activities involved numerous 

radioactive materials

 Amounts changed over time (up and down)

 Some activities and materials still classified

 Internal dose sources included 

 Uranium (depleted, natural) in many physical forms and as the result of 

fires and explosions

 Recycled uranium components

 Enriched uranium was removed in 1974 as source term

 Uranium and thorium progeny

 Thorium (oxides, powders, and metal)
Thorium before 1980

 About 1 ton of thorium transferred from Hood building 

at the start of operations 

 Extruded thorium rods for British and French companies 

in the 1960s

 Converted thorium rods to powder and also extruded 

thorium powder to shapes

 Cast thorium to billet size followed by machining, 

jacketing, extrusion, pickling and machining

 Work with thorium further supported by worker 

outreach meetings
Thorium before 1980 - continued 

 Given the limitations on records

NIOSH identified - 

 A persistent and radiologically significant 

thorium source term over the operating 

history of NMI 

 For which no monitoring existed for the 

period 1958 through 1979 

 Formed part of the basis for the infeasibility 

to reconstruct internal dose up through 1979
Thorium

 Available records at NMI are limited and NIOSH is not 

able to confirm complete access to relevant records

 Others may be lost and are known to have been 

destroyed because it is a closed facility amidst a 

radiological cleanup activity 
Thorium - continued 

 NMI maintained several NRC licenses that provide 

insight

 Requested a thorium limit of 20,000 lbs in 1974

 Requested an increase to 25,000 kg of thorium metal and oxide 

in 1981

 Regarding NRC questions about a 1975 license request, NMI 

responded the material would be 90% thorium minimum and 

they would operate under the same manner for thorium as 

depleted uranium

 NRC stated that NMI/Starmet (subsequent owner of NMI) 

ceased DU munitions work in 1999, that thorium and thorium 

oxide as well as some other materials would continue onsite 
Thorium - continued

 NMI did have two thorium-specific bioassay 

measurements performed in the 1980s

 A single thorium bioassay in 1983

 A single thorium specific in vivo lung count in 1982

 NIOSH found no indications of any routine monitoring 

program involving air monitoring or any other 

bioassay program to support thorium operations
Thorium - continued

 Thorium operations and quantities were 

never detailed during known operation 

periods for programs NIOSH knows used 

thorium

 Perhaps based on compartmentalization 

of programs from classified operations
Thorium - continued

 This practice continued through the entire history of 

NMI

 NIOSH concluded these programs were ongoing and 

significant 

• Interviews with employees, senior NMI management, and 

maintenance and 

• Actual increases to the thorium license limits (to 25,000 kg) 

coupled with the silence in the past on thorium programs

 Given the limitations on records 

• NIOSH identified that a persistent and radiologically

significant thorium source term continued during the 

January 1, 1980 through December 31, 1990 covered period
External Exposure Sources after 1979

 Primarily processing of depleted/natural uranium 

and thorium metal

 Submersion in contaminated air and exposure to 

contaminated surfaces

 Concentration of progeny during metal working and 

separation processes enhanced radiation 

 X-ray sources

• Two industrial X-ray units (by the mid 1960’s there were five 

units)

• 40 mCi unencapsulated Ir-192 source and 45 Ci of Ir-192

• 100 kV medical X-ray machine
External Exposure Sources after 1979

 Personnel monitoring program in place prior to 

relocation of operations to Concord

 In the late 1950s, film badges were issued to all 

uranium processing employees

 In the 1960s, all personnel wore film badges 

(according to documents)

• Processed every 6.5 weeks

• Clerical personnel badges processed annually

• These programs were maintained and improved through the 

end of the covered period
Internal Dose Monitoring Programs and 

Data Availability

 The bioassay program consisted of urinalysis 

samples and lung counts

 Air monitoring program for uranium consists of 

34,400 results available to NIOSH 

• Included breathing zone samples for 1980-90

• Not a single sample attributable to thorium operations
Internal Dose Monitoring Programs and 

Data Availability - continued

 Bioassay program evolved over time according to the 

AEC (NRC) inspection reports

• NIOSH has obtained approximately 44,000 legible urinalysis 

samples for uranium conducted 1980-90

• A single thorium urinalysis sample was found (<0.2 

dpm/sample) from 1983
Internal Dose Monitoring Programs and 

Data Availability - continued

 Lung counts for uranium annually on 

representative sample of employee population 

(approximately 100 per year)

• Approximately 500 lung counts are available for the period 

1982 through 1990

• A single natural thorium specific lung count was identified 

in 1982
Internal Dose Monitoring Programs and 

Data Availability - continued
NMI SEC Petition 195 - continued

Why the class?

 Workers were potentially exposed to thorium and 

thorium progeny who were not monitored nor does a 

suitable dose reconstruction method exist.

 Decision was based on lack of adequate biological 

monitoring data, sufficient air monitoring information, 

and/or sufficient process and radiological source-term 

data to reconstruct dose with sufficient accuracy.
NMI SEC Petition 195 - continued

Why everyone?

 Based on reports by the AEC and facility layout and 

worker interviews, the process areas were not 

isolated from the non-process areas and no barriers 

to access were in place

 NIOSH was unable to find any records on thorium 

operations that would allow it to identify specific 

employees or groups of employees that would limit 

the class
NMI SEC Petition 195 - continued

What about employees not included in the SEC?

 NIOSH will use any internal and external monitoring data that may 

become available for an individual claim (and that can be 

interpreted using existing dose reconstruction processes or 

procedures)

 Therefore, dose reconstructions for individuals employed at 

Nuclear Metals, Inc. during the period from January 1, 1980 

through December 31, 1990, but who do not qualify for inclusion in 

the SEC, may be performed using these data as appropriate

 NIOSH will estimate doses from medical x-rays using information 

from employee medical records and claimant favorable medical 

dose reconstruction assumptions and methods 
Health Endangerment

The evidence reviewed in this evaluation indicates that some 

workers in the class may have accumulated chronic radiation 

exposures through intakes of radionuclides and direct exposure 

to radioactive materials

Consequently, NIOSH is specifying that health may have been 

endangered for those workers covered by this evaluation who 

were employed for a number of work days aggregating at least 

250 work days within the parameters established for this class 

or in combination with work days within the parameters 

established for one or more other classes of employees in the 

SEC
Proposed Class

All Atomic Weapons Employees who worked at the 

facility owned by Nuclear Metals Inc. (or a subsequent 

owner) in West Concord, Massachusetts during the 

period from January 1, 1980 through December 31, 

1990, for a number of work days aggregating at least 

250 work days, occurring either solely under this 

employment or in combination with work days within 

the parameters established for one or more other 

classes of employees included in the Special Exposure 

Cohort. 
Summary

Feasibility Findings for NMI Petition SEC-195 Addendum 

January 1, 1980– December 31, 1990

Source of Exposure Reconstruction Feasible Reconstruction NOT 

Feasible

Internal

 - Uranium All years N/A

 -Thorium N/A No

External

 - Gamma/Photon All years N/A

 - Beta All years N/A

 - Neutron N/A N/A

 - Occ. Medical X-ray All years N/A