Simonds Saw and Steel

Residual Contamination Period

Thomas P. Tomes

NIOSH

Division of Compensation Analysis and Support

July 29, 2014

Idaho Falls, Idaho
Site description

 Lockport, New York

 Atomic Weapons Employer (AWE) 1948 –

1957

 Residual Radiation period 1958 – March 1, 

2011

 Rolled uranium (U) billets into rods for the 

Atomic Energy Commission (AEC) and 

hammered, forged, and rolled thorium (Th) 

metal 
AWE Operations 

 Utilized 16-inch and 10-inch rolling mills and 

hammer forge

 Some U monitoring data, but sparse 

information on Th work and exposures

 Some area cleanup before AEC contract 

ended
Residual Period 

 Fixed contamination and contaminated soil 

remained (primarily U)

 Continued to operate as a steel plant until 

1983 bankruptcy

 Extensive characterizations for radiation and 

contamination 
Special Exposure Cohort Petition 

 NIOSH received petition on December 4, 2009

 Petitioner-requested Special Exposure Cohort 

(SEC) class 

All employees who worked in any area at Simonds Saw and 

Steel, Lockport, New York, during the applicable covered 

operational and residual periods from 1948 through 2006

 Petition qualified for evaluation March 8, 2010 

based on lack of Th monitoring data
Evaluation Report

 NIOSH issued the report on October 29, 2010

 Recommended class of All AWE employees who 

worked at Simonds Saw and Steel from January 

1, 1948, through December 31, 1957

 NIOSH found that doses could be reconstructed 

during the residual period
Board Actions

 On November 16, 2010 , NIOSH presented the 

report to the Advisory Board on Radiation and 

Worker Health (the Board) in Santa Fe, New 

Mexico

 Added SEC class from 1948 through 1957 (HHS designation effective February 5, 2011)

 Postponed the residual contamination period 

discussion until after site profile reviews
Site Profile Review

 In June 2012, SC&A submitted its review of the 

site profile (ORAUT-TKBS-0032 Revision 1) to the 

Board 

 SC&A reported 7 Findings for additional 

evaluation/discussion

 Provided additional observations on the site 

profile
SC&A’s Site Profile Findings

 Findings 1 through 5 

• Comments on various details of the external and internal 

dose models during the AWE operational period (the SEC 

period)

• Discussed by the TBD-6000 Work Group, NIOSH, and 

SC&A and set aside pending a Site Profile revision

 Findings 6 and 7

• Focused on the external and internal doses, respectively, 

during the residual contamination period
Findings 6 and 7

 Finding 6:

More Quantitative and Substantive Discussion of 

Available External Monitoring During the Residual 

Period

 Finding 7:

Appropriateness of Chosen Internal Methodology 

during Residual Period and Consistency with OTIB-0070
Residual Period Radiation Exposures

 Internal Dose: Inhalation and ingestion of U 

and Th from residual contamination

 External dose: Photon and beta exposure 

from residual U and Th contamination

 Analytical data indicates contamination is 

>99% U
SC&A Finding 6 Issues

 More discussion of available radiation survey 

data during the residual period

 Values used to determine the gamma dose 

rate distribution

 Beta dose rates at the 10-inch-bar mill

 Number of work hours used to calculate 

annual doses
Responses to Finding 6

 Dose rate surveys were performed in 1957 after 

clean up and prior to AEC contract ended

 Characterization surveys were performed in 1976 

and 1980 while the plant was still operating

 After plant closure in 1983, characterization 

surveys were performed in 1984, 1999, and 2007
Responses to Finding 6 (cont.)

NIOSH recommended changes to the Site Profile

 Gamma dose rate of 0.08 mR/hour for 2,500 hours per 

year to be applied as a constant

 Beta dose rate of 1.35 mrad/hour for 2,500 hours per year 

to be applied as a constant

 Assumptions are presumed to provide a bounding annual 

dose to operators of the rolling mill after AEC contract 

work ended
SC&A Finding 7 Issues 

 Air concentration at the beginning of the residual 

contamination period

 Explain how Exposure Point Concentrations were 

developed from the 2007 survey data

 Provide additional justification for presuming 

source term depletion ended in 1982

 The number of work hours used to calculate 

intake rates
Responses to Finding 7

Air concentration at the start of residual period:

 Reviewed available data

 Evaluated general area air concentrations measured 

during U rolling operations in 1954

 Proposed a revised value to use for the estimate of 

air concentration at the beginning of the residual 

period
Responses to Finding 7 (Cont.)

The 2007 Exposure Point Concentrations (EPC) were:

 Taken from the U.S. Army Corps of Engineers (USACE) 

Remedial Investigation Report

 Surface contamination data and calculation methods and 

results summarized in the Remedial Investigation Report

 EPC was reported for each building based on thousands 

of measurements of surface contamination data from 

2007

 EPC was the 95% upper confidence limit 
Responses to Finding 7 (Cont.)

NIOSH made additional data requests to the USACE, 

and received:

 Copies of survey reports and maps 

 Survey reports in spreadsheet format

 Spreadsheets used to analyze data

 Other analytical data from the remedial investigation
Responses to Finding 7 (Cont.)

NIOSH evaluated the 2007 contamination data:

 Determined a favorable value for the mostly highly 

contaminated areas, eliminating hundreds of survey 

points of remote areas of the plants and exterior surface

 NIOSH also evaluated contamination data from previous 

characterization in 1999 

 Recommended a revised upper 95% confidence limit 

value based on the building with the highest surface 

contamination
Responses to Finding 7 (Cont.)

Source term depletion response:

 The re-evaluated data is inconclusive on whether source 

depletion continued or ended when rolling mill closed

 Building 24 is an active work area (not isolated), part of it 

has contaminated overhead beams

 NIOSH now recommends assuming depletion throughout 

the residual period by depleting the initial air 

concentration estimates at a rate to agree with the 2007 

air concentration estimates
Summary 

 Revise the Site Profile to address findings and 

comments in the Review

 Proposed changes to the Site Profile were 

discussed with SC&A and the TBD-6000 Work 

Group

 Changes are being made for: 

• partial dose reconstructions for the AWE operational 

period and for full dose reconstructions for the 

residual period
Dose Reconstruction Feasibility

 NIOSH found the available data are insufficient 

to estimate dose from thorium for the AWE 

Contract Period, SEC from 1948 – 1957

 NIOSH determined all doses can be 

reconstructed for the Residual Contamination 

Period, 1958 – March 2011