Nuclear Metals Inc.

Special Exposure Cohort 

Petition Evaluation Report

Samuel Glover, PhD

Research Health Scientist

National Institute for Occupational Safety and Health

Division of Compensation Analysis and Support

September 2012

Denver, CO
Brief Site Overview

 Nuclear Metals, Inc. (NMI) grew out of the 

special metallurgical operations conducted by 

Massachusetts Institute of Technology (MIT) for 

the Manhattan Engineer District which were 

later consolidated into the Hood Building at the 

perimeter of the MIT campus

 NMI took over the MIT operations at the Hood 

Building as a private company and in 1958, 

transferred the operations to Concord, MA
Brief Site Overview—cont. 

 NMI provided the AEC fabrication capabilities 

and metallurgical consulting services for 

uranium, thorium, and many alloys of these 

elements

 In the mid 1970s, NMI began large scale 

fabrication of depleted uranium munitions for 

the US military

 The covered period for NMI as an AWE facility is 

October 29, 1958 through 1990, Residual 

Radiation 1991 through March 1, 2011
Petition Overview

 October 20, 2011: petition received

 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.

 January 17, 2012: petition qualified for 

evaluation based on the potential for 

unmonitored internal radiation exposures
Petition Overview—cont. 

 NIOSH expanded the time period and scope 

evaluated versus that requested by the petitioner

 NIOSH evaluated class:

• All employees who worked at the Nuclear Metals, Inc. 

facility in West Concord, Massachusetts, during the 

period from January 1, 1958* through December 31, 

1983. 

*It was later determined by the Department of Labor 

that the earliest covered period at NMI is October 29, 

1958
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 (9) as well as information from 

claimant telephone interview files (CATIs)

 ATL/ORAUT/NIOSH conducted three outreach 

meetings in Concord attended by approximately 50- 60 former workers and company management 

(some of whom were present from day 1)
Data Capture Efforts

 DOE Opennet (OSTI data base)

 Standard data base search (DDRS, NNSA, CEDR etc.)

 Internet search

 Various DOE locations (OSTI, Hanford, DOE 

Germantown, Legacy Management, Grand Junction, 

Morgantown, Sandia, Savannah river)

 HASL-EML

 Hagley Museum & Library

 NRC

 June 13 ORAU received 16,000 documents from MA 

Department of Environmental Protection
Status of Claims

(as of August 7, 2012) 

 Total number of claims submitted: 23

 Total number of claims who worked

during proposed (SEC): 19

 Total number with a DR (at DOL): 16

 Total number claims with internal dosimetry records: 15

 Total number claims with external dosimetry records: 18
Background

 NMI operated at the Hood Building (a DOE facility) next to 

the MIT campus until October 28, 1958

 NMI at Concord (the subject of the evaluation) was located 

at 2229 Main St, Concord MA on originally 30 acres of land, 

which was later expanded to 46.4 acres (in 1990)

 NMI began transferring operations to Concord after March 

1958 and fully transitioned as of October 29, 1958 at which 

point DOL has determined it became an Atomic Weapons 

Employer (AWE) facility

 Workforce varied from 60 to over 650 workers during the 

time period under review (peaking in the early 1980s)
Background—cont. 

 Original facility consisted of three buildings

• Building A containing office space and research 

laboratories (analytical, x-ray equipment, vacuum 

furnaces)

• Building B contained services (e.g., cafeteria, electrical 

switch room, lockers, etc) and sometimes used as 

needed to hold radioactive materials.

• Building C was the main production facility and 

included equipment for melting metals, extrusion, 

metal working, pickling and etching, and electroplating 
Background—cont. 

 Additional buildings added over time

• Building D (1978) built to expand the production space

• Building E (1983) production area for wet processes 

(pickling, coolant recovery, waste treatment)

• Butler Buildings (BB) were added over time and used 

for storage and sometimes pressed into service as 

needed 

o BB 1 (1958): Primarily non-DU related but over time packing 

and storage of DU components occurred here

o BB 2 (1960) unrestricted access, non-DU purposes

o BB 3 (1976) used for storing DU components

o BB 4 (1977) unrestricted access, non-DU purposes 
Background—cont. 

Diagram of NMI in 1994
Background—cont. 

 Partial listing of operations conducted pre-1972 

• Principally fundamental metallurgy, physical metallurgy, 

chemical metallurgy, engineering and product development, 

fuel element development and manufacture, and manufacture 

of high temperature materials.

 Operations 1972-1979

• Shifted towards large scale production including the 

manufacture of depleted uranium (DU) shields, counter 

weights, armor penetrators, metal powders, beryllium and 

beryllium alloys, and specialty titanium parts

 Post 1979 

• Operations continued, but this period has been reserved for 

further review
Health Physics Program

 NMI had no trained Health Physics staff until 1981

 The program transferred from the Hood Building in 1958

 The programs were research in nature and thus the staff was 

often unaware of new hazards which may be encountered

 Program evolved over many years, and may have periods of 

lapses into poor practices

• Mid-1960s reports describe significant uranium spills and 

contamination which were left unreported

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

contamination controls and monitoring
Health Physics Program—cont.

 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

 While the period after 1979 will be described in a future 

report improvements included

• 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 bioassay samples collected 
Sources of Internal Exposure

 NMI’s research and production activities involved 

numerous sources of exposure

 Amounts changed over time (up and down)

 Some NMI activities and materials remain classified

 Sources of internal dose included

• Uranium (depleted, natural, enriched) in many physical 

forms and as the result of fires and explosions

• Thorium (oxides, powders and metal)

• Uranium and thorium progeny

• Recycled uranium components
Thorium

 Thorium was transferred from the Hood building at the start 

of operations (approximately 1 ton)

 In the 1960s NMI extruded thorium rods for British and 

French companies

 Converted thorium rods to powder

 Extruded thorium powder

 NMI cast thorium to billet size followed by machining, 

jacketing, extrusion, pickling and machining

 Given the limitations on records, NIOSH has identified a 

persistent and radiologically significant thorium source term 

over the operating history of NMI for which no monitoring 

exists for the period 1958 through 1979
Sources of External Exposure

 Processing of depleted/natural/enriched 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 Monitoring Programs and 

Data Availability

 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 1⁄2 weeks

• Clerical personnel badges processed annually
External Dose Monitoring Programs 

and Data Availability—cont. 

Nuclear Metals, Inc. Dosimeter Results Summary

YEAR

Number of Badges

SRDB Reference

YEAR Number of 

Badges

SRDB Reference

1958 98a 25034 1971 604 25046

1959 341b 25034; 28468 1972 364 25046; 25054

1960 1424 28468 1973 433 25054

1961 1196 25038 1974 451 25054

1962 1071 25037 1975 368 25054

1963 828 25037 1976 462e 25054

1964

979c

25037 1977 811 25054; 25072; 113268; 

113279

1965 1284 25037; 29184 1978 942 25054; 25055

1966 902 25045 1979 2615 25054; 25058

1967 617 25045 1980 4230 25054; 29132; 113198

1968 312d 25045; 28465 1981 5422 28481; 28483

1969 622 25040 1982 1970 28582; 28584

1970 688 25046 1983 7739 29151; 29154
External Monitoring Programs and 

Data Availability

 Weekly smear sampling program began in 1958

• Only limited results available to this point

 AEC inspectors remarked (9/18/1969) on 

contamination smears not being taken as required

 Other inspection reports (5/16/1973) indicate direct 

measurement surveys were not recorded on log 

sheets as required 
Internal Dose Monitoring Programs 

and Data Availability

 The bioassay program consisted of urinalysis samples and 

lung counts

 Bioassay program evolved over time due to the AEC (NRC) 

inspection reports

• In 1977, bioassay sampling started increasing

• In 1983, program reportedly consistent with Regulatory Guide 

8.11

• NIOSH currently has identified 2,600 urine bioassay samples 

for uranium between 1958 and 1979 and 12,500 samples for 

the period 1980 through 1983

• No urine samples located to date for 1968, 1972, and 1975
Internal Dose Monitoring Programs 

and Data Availability—cont. 

 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 1986
Internal Dose Monitoring Programs 

and Data Availability—cont. 
Internal Dose Monitoring Programs 

and Data Availability—cont.
Internal Dose Monitoring Programs 

and Data Availability—cont. 
Internal Dose Monitoring Programs 

and Data Availability—cont. 

 NMI maintained an air monitoring program from the earliest 

years

 NIOSH obtained some of the monthly reports for the pre1980 years (31 of 255) with summary data which provide 

average, minimum and maximum concentration data

• Described as having 12 fixed air samplers located throughout the 

plant (increased later)

• 1959 report says that operations involving enriched uranium or 

special jobs of uranium were to have air sampling (results not 

available if implemented)

• 1974 inspection report specifically observed that the fixed head air 

sampling did not approximate worker’s breathing zones

• New data available to NIOSH consists of approximately 28,000 

breathing zone and work area samples (1980-1983)
Summary of Monitoring Gaps

 External

• No neutron monitoring (although limited exposure 

potential) but methods exist which may be suitable for 

estimating dose

 Internal

• The early bioassay program (pre 1980) results are often 

sparse and NIOSH can not verify they represent the worst 

case exposures

• Early air sample data limited and not equivalent to 

breathing zone sampling

• Prior to late 1970s’ difficult to determine if bioassay results 

included incidents

• No results for thorium operations (urine or air)

• No results for radon/thoron sources
NMI SEC Petition 195

 Why the class?

• Workers were potentially exposed to enriched uranium, 

thorium, uranium progeny, 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—cont. 

 Why everyone?

• Based on reports by the AEC and facility layout, the 

process areas were not isolated from the non-process 

areas and no barriers to access were in place.
NMI SEC Petition 195—cont. 

 What about employees not included in the SEC?

• NIOSH intends to 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 October 29, 1958 through December 31, 1979, but who 

do not qualify for inclusion in the SEC, may be performed using 

these data as appropriate. 

• Furthermore, NIOSH intends to estimate doses from medical xrays using information from employee medical records and 

claimant favorable medical dose reconstruction assumptions 

and methods. 
NMI SEC Petition 195—cont. 

 Why stop in 1979?

• Because the continuing analysis affects only post-1979, 

NIOSH has determined that it is appropriate to proceed 

with the pre-1980 feasibility evaluation while continuing 

to analyze the impact that newly obtained data have on 

post-1979 dose reconstruction. NIOSH is therefore 

reserving its full assessment of the available post-1979 

data and will continue to evaluate the feasibility of 

sufficiently accurate dose reconstruction for the period 

from January 1, 1980 through December 31, 1983.
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 October 

29, 1958 through December 31, 1979, 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. 
Recommendation

 For the period October 29, 1958 through 

December 31, 1979, NIOSH finds that radiation 

dose estimates cannot be reconstructed for 

compensation purposes

Class Feasibility Health Endangerment

October 29, 1958 –

December 31, 1979 No Yes