Draft White Paper 

EVALUATION OF NIOSH’S RESPONSE TO SC&A’S 


CONCERNS REGARDING DWE ERRORS (BLUNDERS) IN 


WELDON SPRING DATA 


Contract Number 200-2009-28555 

Prepared by
 

Ron Buchanan, PhD, CHP 


S. Cohen & Associates 


1608 Spring Hill Road, Suite 400 


Vienna, Virginia 22182 


Saliant, Inc.
 

5579 Catholic Church Road 


Jefferson, Maryland 21755 


January 2012 


Disclaimer 

This document is made available in accordance with the unanimous desire of the Advisory Board on 

Radiation and Worker Health (ABRWH) to maintain all possible openness in its deliberations. However, 

the ABRWH and its contractor, SC&A, caution the reader that at the time of its release, this report is predecisional and has not been reviewed by the Board for factual accuracy or applicability within the 

requirements of 42 CFR 82. This implies that once reviewed by the ABRWH, the Board’s position may 

differ from the report’s conclusions. Thus, the reader should be cautioned that this report is for 

information only and that premature interpretations regarding its conclusions are unwarranted. 
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S. COHEN & ASSOCIATES: 

Document No. 

Response to NIOSH – DWE Error Issue 

Technical Support for the Advisory Board on 

Radiation & Worker Health Review of 

Effective Date: 

Draft – January 17, 2012 

NIOSH Dose Reconstruction Program Revision No. 

0 (Draft) 

Evaluation of NIOSH’s Response to SC&A’s 

Concerns Regarding DWE Errors (Blunders) in 

Weldon Spring Data 

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Task Manager: 

________________________ Date:____________ 

Ron Buchanan, PhD, CHP 

Supersedes: 

N/A 

Project Manager: 

________________________ Date:____________ 

John Stiver, CHP 

Peer Reviewer(s): 

Joseph Fitzgerald 

John Stiver 

Record of Revisions 

Revision 

Number 

Effective 

Date Description of Revision 

0 (Draft) 01/17/2012 Initial issue 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 


However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 


Health for factual accuracy or applicability within the requirements of 42 CFR 82.
 
 

Effective Date: 

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1.0	 INTRODUCTION 

On September 7, 2011, the National Institute for Occupational Safety and Health (NIOSH) 

provided a response (NIOSH 2011a, Rev. 00) to the Weldon Spring Site (WSS) Special 

Exposure Cohort (SEC) issue (SC&A 2010) concerning errors, or sometimes called “blunders,”1 

in the original daily weighted exposure (DWE), or sometimes referred to as daily weighted 

average (DWA), air concentration data as discussed at the WSS Work Group meeting of May 9, 

2011. On September 27, 2011, SC&A issued an evaluation of that paper (SC&A 2011). 

On November 28, 2011, NIOSH issued Rev. 01 to their original September 7, 2011, paper 

(NIOSH 2011b). 

The following presents SC&A’s evaluation of NIOSH’s November 28, 2011, Rev. 01, response. 

Note that many of the concerns expressed in SC&A 2011 have not been resolved in NIOSH 

2011b and are retained in this response. 

2.0	 SC&A’S EVALUATION OF NIOSH’S NOVEMBER 28, 2011, RESPONSE TO 

WSS ISSUE #1b, ERRORS IN DWE DATA 

SC&A evaluated NIOSH’s response to the issue of errors in the DWE original data and found 

the following. 

(1)	 Limited data – NIOSH’s white paper indicated that about 20 DWE reports were 

available and suitable for analysis. Nine Site Research Database (SRDB) documents 

were located that contained dust studies and DWE evaluations. Of these, there were 81 

pages that contained calculations that were of interest. These pages contained 1,405 

operations that were used to estimate the error rate. NIOSH indicated that the 

calculations were duplicated in all cases except those where errors were noted. However, 

SC&A noted that not all of the available raw data were included in the error analyses. 

NIOSH 2011b is silent on why some of the data were excluded from the analysis. 

Although NIOSH acknowledges that the available raw data are a “small” proportion of 

the total DWE data set that will be used in dose reconstruction (DR), they do not quantify 

that proportion (i.e., what percentile). The DWE datasets to be used in DR are identified 

in Tables 6-4 (uranium) and 6-5 (thorium) of the SEC-00143 petition evaluation report 

(NIOSH 2010). 

(2)	 Representativeness of the limited data – NIOSH’s report does not indicate the extent to 

which the available raw data are representative of the DWE data identified in NIOSH 

(2010). It is not clear from the report if the evaluated data pertain to the highest DWEs 

for each building, year, and job category. For example, SRDB 14945 contains 27 pages 

of raw data calculations that are applicable to the metals plant (Building 301) in the years 

1958–1959. However, Table 6-4 (uranium) of NIOSH 2010 contains no DWEs for 

1 The ISO definition emphasizes that a blunder is often considered a serious mistake caused by ignorance 

or confusion; stupidity, which is included in some U.S. English definitions of blunder, is not implied in this case 

(ISO 1995). 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 


However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 


Health for factual accuracy or applicability within the requirements of 42 CFR 82.
 
Effective Date: 

January 17, 2012 

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Building 301 in 1958, and only one value for one operation in 1959; that value is the 

second lowest DWE for Building 301 for all 7 years reported. 

SC&A’s analyses of the DWE data used by NIOSH indicate that out of the 82 lines of 

data on pages 9–14 (1958–1965), only 17 correspond to the period when the thorium 

DWE data were taken (1963–1966). Unfortunately, the thorium DWE datasheets only 

contain the building number, job title, year, DWE results, and some information 

concerning the month(s) when samples were taken, but no exact dates or raw data. Thus, 

it would appear difficult to correlate the DWE data NIOSH used to determine errors 

directly to the thorium intake data. SC&A found that in many entries, the building 

numbers and dates listed in the 82 lines of data on pages 9–14 of the NIOSH Rev. 00 and 

Rev. 01 papers were incorrect (NIOSH 2011a and NIOSH 2011b). SC&A corrected 

these errors before analyzing the data. 

Another aspect of representativeness involves the personnel who performed data 

transcription and reduction at different times (referred to herein as “operators”). SC&A 

is concerned that different operators may have been involved in thorium data 

transcription and reduction than those represented by the limited NIOSH dataset. If so, 

the attributes of the errors and their influence on DWE during thorium operations could 

be quite different from those identified in NIOSH 2011b. 

(3)	 Type and Magnitude of Error – Notwithstanding our concerns regarding 

representativeness of the limited dataset, SC&A notes that the types and relative 

magnitudes of the errors identified in NIOSH’s white paper are similar to those found in 

Davis and Strom (2008). That is, the average error resulted in about a factor of 2 

underestimate, while the largest errors resulted in an order of magnitude underestimate. 

(4)	 Application of Findings – NIOSH’s Rev. 01 of the white paper (NIOSH 2011b), 

Section 4, presents an evaluation of the impact that errors could have on the resulting 

thorium intakes assigned during the DR process. A Monte Carlo simulation of the impact 

of the errors observed in the 82 lines of the dataset listed on pages 9–14 of the NIOSH 

Rev. 01 paper (NIOSH 2011b) indicates that the error rate and distribution of observed 

errors would result in approximately a 4% decrease (95th percentile level) in the intakes 

assigned. Therefore, if the type, magnitude, and frequency of the observed errors in this 

limited dataset are assumed to be representative of those common to the thorium DWE 

data, the assigned intakes would have to be increased by about 4% to compensate for 

errors in the DWE data. 

3.0 SUMMARY 

As previously stated in SC&A’s evaluation of September 27, 2011 (SC&A 2011), SC&A 

believes that NIOSH should address the representativeness of the limited available uranium raw 

data to the dataset used by NIOSH in determining the error rate in thorium DWE data to be 

applied during DR. Only 17 of the 82 lines of data were recorded during the period that the 

thorium intake data were taken (1963–1966), and these have not been determined to be 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 


However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 


Health for factual accuracy or applicability within the requirements of 42 CFR 82.
 
Effective Date: 

January 17, 2012 

Revision No. 

0 (Draft) 

Document No. 

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representative. Additionally, though not all available raw data were included in the error 

analyses, no explanation of the criteria for inclusion/exclusion is provided by NIOSH. 

4.0 REFERENCES 

Davis A. J. and D.J. Strom, 2008. Uncertainty and Variability in Historical Time-Weighted 

Average Exposure Data, [Journal] Health Physics. Vol. 94. February 2008. SRDB 41616. 

NIOSH 2010. SEC Petition Evaluation Report, Petition SEC-00143, Rev. 0. National Institute 

for Occupational Safety and Health, Office of Compensation Analysis and Support, Cincinnati, 

Ohio. April 16, 2010. 

NIOSH 2011a. White Paper for Weldon Spring Plant - Evaluation of Blunders Associated with 

Daily Weighted Average (DWA) Reports at the Weldon Spring Plant, Rev. 00. National Institute 

for Occupational Safety and Health, Office of Compensation Analysis and Support, Cincinnati, 

Ohio. September 7, 2011. 

NIOSH 2011b. White Paper for Weldon Spring Plant - Evaluation of Blunders Associated with 

Daily Weighted Average (DWA) Reports at the Weldon Spring Plant, Rev. 01. National Institute 

for Occupational Safety and Health, Office of Compensation Analysis and Support, Cincinnati, 

Ohio. November 28, 2011. 

ISO 1995. “Guide to the expression of uncertainty in measurement.” International Organization 

for Standardization, Geneva. 1995. 

SC&A 2010. Preliminary Issues from SC&A’s Review of NIOSH’s Evaluation Report for the 

Weldon Spring Site, Weldon Spring, Missouri, Special Exposure Cohort Petition SEC-00143. 

SCA-TR-TASK5-0015. SC&A, Inc., Vienna, Virginia, and Saliant, Inc., Jefferson, Maryland. 

October 2010. 

SC&A 2011. SC&A’s Evaluation of NIOSH’s Response of September 7, 2011, to Daily 

Weighted Exposure Blunders in Weldon Spring Data. SCA-TR-TASK5-0015. SC&A, Inc., 

Vienna, Virginia, and Saliant, Inc., Jefferson, Maryland. September 2011. 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 


However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 


Health for factual accuracy or applicability within the requirements of 42 CFR 82.