Draft 

ADVISORY BOARD ON 

RADIATION AND WORKER HEALTH 

National Institute for Occupational Safety and Health

REVIEW OF THE NIOSH SITE PROFILE FOR THE 

HOOKER ELECTROCHEMICAL COMPANY 

Battelle-TBD-6001, Appendix AA 

Contract No. 200-2009-28555 

SCA-TR-SP2010-0034 

Prepared by 

William C. Thurber 

S. Cohen & Associates 

1608 Spring Hill Road, Suite 400 

Vienna, VA 22182 

September 2010 

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 42CFR82. 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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Document No. 

SCA-TR-SP2010-0034 

Effective Date: 

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S. COHEN & ASSOCIATES: 

Technical Support for the Advisory Board on 

Radiation & Worker Health Review of 

NIOSH Dose Reconstruction Program

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REVIEW OF THE NIOSH SITE PROFILE FOR THE 

HOOKER ELECTROCHEMICAL COMPANY Page 2 of 28 

Task Manager/Lead Author: 

______________________________ Date:____________ 

William C. Thurber, M.S. 

Supersedes: 

N/A 

Project Manager: 

______________________________ Date:____________ 

John Mauro, Ph.D., CHP 

Peer Reviewer(s): 

 John Mauro 

 Greg Hofer 

Record of Revisions 

Revision 

Number 

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Date Description of Revision 

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TABLE OF CONTENTS 

Acronyms and Abbreviations ..........................................................................................................4 

1.0 Statement of Purpose ...........................................................................................................6 

2.0 Introduction..........................................................................................................................7 

3.0

................................................................................................................................9 

Review of Sections AA.2 through AA.6 of Appendix AA: Observations and/or 

Findings

3.1 Review of Section AA.2 “Site Description”............................................................9 

3.2 Review of Section AA.3 “Occupational Medical Dose” .........................................9 

3.3 Review of Section AA.4 “Occupational Internal Dose”..........................................9 

3.4 Review of Section AA.5 “Occupational External Dose”.......................................12 

3.5 Review of Section AA.6 “Residual Contamination”.............................................14 

3.5.1 Estimate of Inhalation Quantity from Residual Contamination ................15 

3.5.2 Estimates of External Dose from Residual Contamination .......................16 

4.0 Use of Surrogate Data........................................................................................................18 

5.0

..............................................................................................................20 

Summary, Conclusions, and Initial Impressions Regarding the SEC Petition and 

Evlauation Report

6.0 References..........................................................................................................................22 

Attachment 1: Issues Matrix for TBD-6001 as of June 14, 2010 .................................................24 
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ACRONYMS AND ABBREVIATIONS 

ABRWH Advisory Board on Radiation and Worker Health 

AEC Atomic Energy Commission 

AMAD Activity Median Aerodynamic Diameter 

AWE Atomic Weapons Employer 

Ci curies 

cm3 cubic centimeter 

DOE U.S. Department of Energy 

dpm disintegrations per minute 

Electro-Met Electro Metallurgical Company 

EU enriched uranium 

g gram 

g/cm3 grams per cubic centimeter 

GM Geometric Mean 

gpm gallons per minute 

GSD Geometric Standard Deviation 

HASL Health and Safety Laboratory 

HCl hydrochloric acid 

m meter 

m3 cubic meter 

MCNP Monte Carlo N-Particle 

MED Manhattan Engineer District 

mg milligram 

mR milli roentgen 

mrad milliradian 

mrem millirem 

mrep millirep 

m/s meters per second 

NIOSH National Institute for Occupational Safety and Health 

ORAUT Oak Ridge Associated Universities Team 

pCi/d picocuries per day 

pH measure of acidity 
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NOTICE:

RU recycled uranium 

SC&A S. Cohen and Associates (SC&A, Inc.) 

SEC Special Exposure Cohort 

TBD Technical Basis Document
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1.0 STATEMENT OF PURPOSE 

The purpose of this report is to provide a critical review of Battelle-TBD-6001, Appendix AA, 

Hooker Electrochemical Corporation. In this report, we assess the merit and technical basis of 

the data and guidance to be used for dose reconstruction. This review was authorized by the 

Advisory Board on Radiation and Worker Health (ABRWH) at its May 2010 meeting in Niagara 

Falls, New York. 

At about the same time, the National Institute for Occupational Safety and Health (NIOSH) 

issued a review of Special Exposure Cohort (SEC) Petition SEC-00141 covering Hooker 

Electrochemical (NIOSH 2010). SC&A was not tasked with a review of the petition evaluation 

report; however, as we have done in the past in similar situations (e.g. our review of the United 

Nuclear Corporation site profile), we provide some initial impressions regarding possible SEC 

issues, based on reading the petition and the evaluation report. A more detailed review of the 

petition and evaluation report will be performed if so authorized by the ABRWH.
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2.0 INTRODUCTION 

On June 15, 2007, NIOSH issued Appendix AA to Battelle-TBD-6001, which provides data and 

guidance for dose reconstruction of workers employed at an Atomic Weapons Employer (AWE) 

site—the Hooker Electrochemical Company (Hooker) in Niagara Falls, New York. This facility 

processed uranium-bearing (C-2) slags from July 11, 1944, to January 15, 1946. The operations 

at the Hooker facility involved treatment of C-2 slag from the nearby Electro Metallurgical 

Company (Electro-Met) with hydrochloric acid (HCl) to recover uranium. The C-2 slag from 

Electro-Met was a byproduct of the bomb reduction process, in which uranium tetrafluoride was 

reacted with magnesium to produce uranium metal. The HCl was excess acid produced at 

Hooker under AEC contract as a byproduct from the non-radioactive P-45 process. 

Slag from Electro-Met was shipped in wooden barrels to Hooker by rail (DOE 1977, MED 1944). 

Each barrel was filled with 500 lbs of slag (reduction bomb liners) with the nominal composition 

of 90% MgF2 and 10% CaO, plus about 1 lb of natural U (0.2%) (MED 1944). It is assumed 

here that the barrels were unloaded from the rail cars and initially stored on a concrete pad at the 

rail siding. The barrels were then opened and dumped on a bucket conveyor, which carried the 

slag over a 20 mesh screen, with the undersize being conveyed to one of three wooden digestion 

tanks (MED 1944, although DOE 1985 says that 4 tanks were used). Oversize from the 

screening was drummed and returned to Manhattan Engineer District (MED) control. 

After 40 barrels were loaded into a 13-ft diameter by 11-ft high wooden digester tank (Dowling 

1944, p. 112), HCl was added and the pH was adjusted to 4.0 with water additions (MED 1944). 

Digestion of the agitated slurry continued for about 20 hours (MED 1944). Operators standing 

on platforms above the tanks then added lime from 100-lb bags to neutralize the slurry (MED 

1944). The neutralized slurry was pumped to a plate and frame filter press, where the filtrate 

was collected and discharged into a sewer. The filter cake was then washed several times. The 

filter cake containing 5 to 10 lbs of U (per 500 lbs of residue or 1 to 2% U) was then re-drummed 

in wooden barrels and shipped by rail to MED control (MED 1944). The turnover rate for a 

digester tank was stated to be once every 2 days (MED 1944). The digester tanks, bucket 

elevator, and filter press were housed in a cinder block building specifically constructed for the 

process (Dowling 1944, p. 112). The other operations, such as handling of barrels, were 

conducted outdoors. 

The volume of the slurry in a digester tank based on 20% free-board is about 1,200 ft3

. 

Assuming that the digester feed is MgF2 with a density of about 187 lb/ft3

, the addition of 

20,000 lbs of slag to a tank would produce a slurry initially containing about 10% solids. 

According to http://www.mine-engineer.com/mining/plate.htm, a 50 ft2

 plate and frame filter 

press can dewater 10% solids at 50 gpm. Accordingly, it would take about 3 hours to dewater 

the contents of a digester tank, and that operation would occur about every second or third day 

for each digester. It is not known how much time would be required to unload the press and 

transfer about 2,000–4,000 lbs of product into barrels and how much time would be spent in 

other routine operations around the filter press. 

Magnesium fluoride has very low solubility in water, but its solubility is significantly increased 

in HCl solutions with a pH of 4 or less (Johnson et al. 1954). Based on a 10-ton charge into a 
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. 

 

NOTICE:

digester, 8 tons of MgF2 and CaO would need to be dissolved to achieve a concentration of 1% 

U in the product residue, or 9 tons dissolved for a concentration of 2% U

Four operators handled the process that involved 200 manhours per week (MED 1944). The 

maximum production rate was 10 tons per month (MED 1944), and a total of 152 tons were 

produced from July 1944 through January 15, 1946 (Battelle-TBD 6001, Appendix AA).1 

Assuming that the filter cake contained 10 lbs of U (per 500 lbs of residue), then based on a 

production rate of 10 tons per month, 100 tons per month of slag would need to be processed. 

This would require 10 digester batches per month. 

Before proceeding with the review, it should be pointed out that Appendix AA relies heavily on 

TBD-6001. SC&A reviewed TBD-6001, and a work group meeting was held to go over our 

findings. Attachment 1 presents the issues matrix for TBD-6001 as of April 14, 2010. 

1

 Another source states that the plant was shut down in October 1945 (Young 1985). 
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3.0 REVIEW OF SECTIONS AA.2 THROUGH AA.6 OF APPENDIX AA: 

OBSERVATIONS AND/OR FINDINGS 

Appendix AA of Battelle-TBD-6001 is a brief document consisting of 10 pages that include 

5 pages of text and 4 tables. Our review follows the sequence of topics as presented in 

Appendix AA. 

3.1 REVIEW OF SECTION AA.2 “SITE DESCRIPTION” 

As discussed in more detail in Section 3.3, we question whether it is reasonable to assume that 

transfer of 400 barrels of slag to the digestion process could be accomplished in 1 day per month. 

3.2 REVIEW OF SECTION AA.3 “OCCUPATIONAL MEDICAL DOSE” 

Based on available information, NIOSH recommends that each worker be assumed to have had a 

pre-employment physical, and that exposures be based on guidance provided in ORAUT-OTIB0006 (ORAUT 2005). As SC&A pointed out in its review of the Electro-Met SEC petition 

(SC&A 2010), estimates of occupational medical exposure should be based on 

photofluorography, unless there is evidence that this technique was not used at AWE sites and 

only at Department of Energy (DOE) sites. 

Observation 1: NIOSH should clarify whether or not photofluorography was used at AWE sites. 

3.3 REVIEW OF SECTION AA.4 “OCCUPATIONAL INTERNAL DOSE” 

NIOSH assumed that an operator would spend 1 day per month, or 5% of his/her time, dumping 

slag from barrels onto the conveyor for screening and transfer to the digesters. As described in 

Section 2.0 above, if the process product contained 2% U and the monthly output was 10 tons, 

then 100 tons of C-2 slag would need to be processed monthly. This would require dumping of 

400 barrels, assuming that all the material was minus 20 mesh. However, some unknown 

fraction was oversized, so more than 400 barrels would be dumped in a month to obtain the 

required amount of minus 20 mesh feedstock. It seems unlikely that an operator using a fork lift 

truck could open a barrel, move the barrel from the storage pad to bucket conveyor (or a feed 

hopper), dump the barrel, and place the empty barrel back on the storage pad in about 1 minute. 

In addition, time would be required to re-package the +20 mesh fraction and the leached product 

in barrels. Repackaging of the product should cause limited additional inhalation exposure, 

because the filter cake would be moist. 

Finding 1: NIOSH should re-examine the assumption that dumping of barrels could be done in 

1 day per month. 

In Table AA.1, Internal Dose Pathways, NIOSH lists 156 pCi/d as the inhalation intake for an 

operator. According to NIOSH, this is based on Table 8.29 of TBD-6001, where a median 

inhalation intake rate of 2,920 pCi/calendar-day is quoted for a scrap recovery furnace operator 

(1951 and earlier) handling trays of scrap. NIOSH observed that the inhalation intake of 

2,920 pCi/calendar-day was based on a geometric mean uranium concentration of 822 dpm/m3

, 
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which translates to a total dust loading of 293 mg/m3 (Appendix AA, Section AA.4). This very 

high dust loading might be expected from very dusty operations, such as dumping of slag from 

the barrels. 

Using the NIOSH assumption that exposure to dust occurred 5% of the time, the calculated daily 

exposure for an operator would be 146 pCi/d (2,920 pCi/calendar-day × 0.05 exposure days/ 

calendar-day), a value similar to that in Table AA.1. However, this approach neglects the 

exposure from other operations involving the digester and the filter press, and underestimates the 

time required to handle the barrels of slag. 

Since it is estimated that about 10 batches per month were processed through the digesters, and a 

digester was turned over once every 2 days, then one could assume that the balance of the 

operator’s time during the month was spent in processing material through the digesters and 

filtering the acid-digested product. According to Table 8.29 of TBD-6001, a digest operator 

involved in scrap recovery prior to 1951 had an inhalation intake of 28.4 pCi/calendar-day 

(based on a 48-hr work week) and a filtration operator had an intake exposure of 

10.7 pCi/calendar-day.2 Assuming that the operator spent 75% of the time working around the 

digester and 20% of the time working around the filter press, this would add 23 pCi/calendar-day 

or about 15% to the operator’s exposure (28.4 × 0.75 + 10.7 × 0.20). 

Finding 2: NIOSH should account for all activities causing inhalation exposure, not just those 

involved in dumping barrels of C-2 slag. 

NIOSH assumed that it was appropriate to use the median value from Table 8.29 of TBD-6001 

as a bounding value for exposures at Hooker Chemical. NIOSH said that this approach was 

reasonable, since the data in Table 8.29 are based on exposures from uranium and/or its 

compounds, rather than material initially containing only 0.2% U. While there is no doubt that 

the uranium concentration in the dust from slag processing operations is significantly lower than 

from the scrap recovery operations characterized in Tables 8.24 and 8.29 of TBD-6001, it is not 

clear that reducing the measured data to the median and then assuming that the median is 

bounding is claimant favorable absent further analysis. For example, statisticians generally 

regard the arithmetic average as the expected value of a distribution. Thus, the expected value 

for the dust concentration experienced by furnace operators involved in scrap recovery is 

3,000 dpm/m3

 (TBD-6001, Table 8.23), as compared to an estimated median of 822 dpm/m3

(TBD-6001, Table 8.24). The assumption that 156 pCi/day is bounding for operators at Hooker 

is based on several factors, which may or may not be sufficiently conservative to account for 

uncertainties: 

 The operator is exposed to uranium-bearing dust 5% of the time 

 The median is the appropriate metric for the expected exposure 

 The operator experiences no other exposure for the remaining 95% of his/her time 

 2

 The dust loadings in TBD-6001 are based on an extensive database of plant measurements summarized by 

Christofano and Harris (1960). 
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 The scrap material on which the analysis was based may not be solely uranium. As 

noted by Christofano and Harris (1960), “Scrap as it enters the recovery plant might be 

high-purity uranium metal (99%), low-grade ore, slag and dross from remelting 

operations, or thermite-reduction bomb linings.” Thus, it may not be appropriate to 

reduce exposures by a factor of 500 based on the slag composition of 0.2% U. 

An alternative approach that could be considered is to use data in TBD-6001 related to the 

digestion of uranium ore (TBD-6001, Table 8.2). The nature of the ore is better documented [it 

contains 20% to 50% U3O8, per Christofano and Harris (1960)], and the digestion process 

includes opening and dumping drums, digesting the concentrate in acid, and filtration, processes 

conceptually similar to those practiced at Hooker. Using the information from Table 8.2 

precludes the need to assume a distribution of time spent among the various aspects of the acid 

treatment process and speculation on the uranium content of the scrap. Table 8.2 of TBD-6001 

lists dust concentrations (average daily exposures in dpm/m3) associated with ore digestion as 

follows: 

Minimum Maximum Average

7 350 110 

Equal contributions to alpha activity in the ore are made by U-238, U-234, Th-230, and Ra-226. 

Thus, the values from Table 8.2 must be reduced by a factor of two to account for uranium only. 

From this information, one calculates the parameters for a lognormal distribution using 

procedures described in Section 2.1.2.3 of Strom 2007 as follows: 

GM = 24.7 dpm/m3

μ = 3.21 

σ = 1.26 

GSD = 3.54 

If one assumes that the 95th percentile is bounding, the limiting air concentration would be 

198 dpm/m3

, which is equivalent to 704 pCi/calendar-day (198 dpm/m3 × 1.2 m3/hr × 8 hr/workday × 6 work-days/week × 50 weeks /yr × 1 yr/365 calendar-days × 1 pCi/2.22 dpm). The 

uranium ore contains 20% to 50% U3O8 (Christofano and Harris 1960), so we will assume an 

average concentration of 35% U3O8 or 30% U. However, the C-2 slag processed at Hooker 

contains only 0.2% U, so the ore exposure must be reduced by a factor of 150 (30%/0.2%) to 

obtain an exposure representative of slag or 4.7 pCi/calendar-day. This value is substantially 

below the 156 pCi/calendar-day assumed by NIOSH in Table AA.3, indicating that the NIOSH 

approach is claimant favorable and bounding in spite of our concerns about some of the 

underlying assumptions. 

One could also consider use of the data from concentrates in Table 8.2. In the case of 

concentrates, no adjustment is required for Th-230 and Ra-226, as these radionuclides would 

have been removed in the processing of ore to concentrates. Since the minimum, maximum, and 

average values for concentrates do not fit a lognormal distribution, Strom (2007, Section 2.1.2.4) 

recommends using the average and an assumed geometric standard deviation (GSD) of 5 to 

calculate lognormal parameters. This approach results in a 95th percentile value of 153 dpm/m3, 

which is equivalent to an inhalation intake of 544 pCi/calendar-day. The concentrates contain an 
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average of 80% U3O8 (Christofano and Harris 1960) or 68% U. Adjusting the concentrate 

exposure for the uranium content of the slag (68%/0.2%) results in an estimated inhalation intake 

of 1.6 pCi/calendar-day, providing another benchmark indicating that the NIOSH approach is 

conservative. The data selected by NIOSH from TBD-6001 were based on scrap recovery 

operations that are quite different from those practiced at Hooker and resulted in inhalation 

intakes that were higher by factors ranging from 30 to 100, as compared to those from other 

operations described in TBD-6001 that are more akin to the Hooker process. It is arguable that 

the selected approach, while claimant favorable, may not be plausible. 

Finding 3: While SC&A does not agree with some of the underlying assumptions in their 

approach, the NIOSH approach appears to be bounding for dose reconstruction. However, our 

independent analyses indicate that the values for intake rate are unrealistically high. 

3.4 REVIEW OF SECTION AA.5 “OCCUPATIONAL EXTERNAL DOSE” 

Since no monitoring data were available, NIOSH used the median values from Table 7.3 of 

TBD-6001 for workers involved in scrap recovery. Values for whole-body dose from external 

exposure pathways are presented in Table AA.3. According to Section AA.5, the operator is 

assumed to spend 5% of the time exposed to both surface (floor) contamination (0.376 mR/ 

calendar-day) and exposure from handling barrels (0.528 mR/calendar-day), and 95% of the time 

exposed only to surface contamination, resulting in an external exposure of 0.402 mR/ calendar 

day ([0.376 + 0.528] × 0.05 + 0.376 × 0.95). However, as discussed by SC&A in its review of 

TBD-6001, Table 7.3 is lacking in transparency, making it difficult for the reader to trace the 

values in that table to their sources. For example, Table 7.3 lists the median exposure based on a 

48-hr week for a scrap recovery operator from material handling as 0.528 mR/ calendar-day. 

Presumably this exposure rate is derived from information provided in Table 7.1. In Table 7.1, 

we find that the exposure from scrap recovery is 2.25 mR/8-hr work-day3

, which can be 

converted to 1.84 mR/calendar-day (2.25 mR/work day × 6 work-days/work week × 50 work 

weeks/yr × 1yr/365 calendar-days). If one assumes that this (i.e., 1.84 mR/calendar-day) is the 

arithmetic average for a lognormal distribution with a GSD of 5, then the geometric mean (GM) 

would be 0.504 mR/calendar-day, a value similar to 0.528 mR/calendar-day reported in Table 

7.3 of TBD-6001. We believe that the difference may be due to the fact that the authors of TBD6001 assumed 350 calendar-days per year, rather than 365 calendar-days per year. If we are 

correct in this interpretation of the values, such a description should be included in the TBD. 

Observation 2: If conversion of external exposure to a calendar-day basis is based on 350 days 

per year, the basis for this assumption should be provided. In addition, NIOSH should provide 

example calculations to show how the values in Table 7.3 of TBD-6001 were derived. 

Table 7.3 lists the median exposure to an operator standing on a contaminated surface as 

0.376 mR/calendar-day. NIOSH provided information to assist SC&A in understanding the 

source of this exposure metric, since it could not be readily derived from the information in 

3

 This value is traceable to MicroShield calculations summarized in Table 7.2 of TBD-6001. The exposure 

calculated by MicroShield assumes that the worker spends 100% of the time 1 m from a 55-gallon drum containing 

uranium compounds and was doubled to account for Bremsstrahlung radiation. 
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TBD-6001 (Allen 2010). The starting point was general area samples taken near a scrap 

processing furnace (TBD-6001, Table 8.23), which list average values of 900 dpm/m3 (trays) and 

200 dpm/m3 (calciner), yielding an average value of 550 dpm/m3. This was converted to a GM 

of 151 dpm/m3, assuming that the data were described by a lognormal distribution with a GSD of 

5. Assuming deposition for 1 year at a deposition velocity of 7.5E-04 m/s, the contamination 

factor is 2.37E+04 m and the annual areal deposition is 3.57E+06 dpm/m2

 (151 dpm/m3 × 

2.37E+04 m). From this, the exposure rate can be determined to be 0.002 mR/hr using the 

conversion factor in Table 3.10 of TBD-6001 of 5.61E-10 mR/hr per dpm/m2

. Due to 

spreadsheet error, the hourly exposure had been calculated to be a factor of 100 higher. This 

means that external exposure from contaminated surfaces has been overstated in Table AA.3 by 

a factor of about 30. 

Finding 4: NIOSH should correct the external exposure rates in Table AA.3. 

The values in Table AA.3 are based on the median and assumed to be constant. NIOSH argues 

that use of the median rather than the full distribution is appropriate for a bounding calculation 

because the uranium concentration in the slag is low (i.e., 0.2%). In contrast, the uranium source 

term for materials handling in Table 7.3 of TBD-6001 is based on exposure to 55-gallon drums 

containing loosely packed uranium (or U308)

4

 with a density of 1.6 g/cm3 that has decayed for 

100 days after refining. Based on the specific activity of natural uranium of 684 pCi/mg, the 

drum would contain 1.09E+06 pCi/cm3. The equivalent U content in the C-2 slag would be 

4.35E+03 pCi/cm3 based on an MgF2 density of 3.18 g/cm3

 (0.002g U/g MgF2 × 

3.18 g MgF2/cm3 × 684 pCi/mg U × 1,000 mg/g). The fact that the curie density in 55-gallon 

drums is about 2.5 orders of magnitude greater than in the C-2 slag supports the use of the 

median from Table 7.3 as the upper bound for materials handling exposures at Hooker. However, 

a more robust approach would be to calculate external exposures specific to Hooker by modeling 

barrels of slag with MCNP or MicroShield. 

Finding 5: Rather than applying the values in Table 7.3 as default/bounding values, NIOSH 

should derive the correct external dose values using MicroShield or MCNP. 

NIOSH provides information on skin doses in Table AA.4. (This is incorrectly labeled 

Table AA.3 in Appendix AA). The dose to the hands is based on Table 7.3 of TBD-6001. The 

median dose to the hands of a scrap recovery operator working 48 hours per week is listed as 

219 mrem/calendar-day. Assuming that the operator’s hands are in close contact with the slag 

for 5% of the time, the dose would be 11 mrem/calendar-day. Table AA.4 lists the dose as 

11 mR/d. 

Observation 3: For consistency with the TBD-6001 source document, the units in Table AA.4 

should be specified as mrad or mrem/calendar-day rather than mR/calendar-day. 

The source of the median dose to the hands in Table 7.3 appears to be based on Table 3.4 of 

TBD-6001. Table 3.4 lists the exposure to the hands in contact with a slab of uranium as 

4

 Section 7.3 of TBD-6001 does not specify the material in the drums and should do so to improve 

document clarity. 
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233 mrad/hr, which in turn stems from measurements reported in DOE 2004. If one assumes 

that 233 mrad/hr is the average of a lognormal distribution with a GSD of 5, the median value is 

64 mrad/hr. As modeled, the operator has his/her hands in contact with the uranium metal slab 

50% of the work-day (TBD-6001, Section 3.3.1), resulting in a dose of 219 mrad/calendar-day as 

shown in Table 7.3 of TBD-6001 (64 mrad/hr × 0.5 × 8 hr/work-day × 300 work-days/ 

365 calendar-days = 210 mrad/calendar day, a value similar to that in Table 7.3). Based on the 

assumption that barrel handling occurs on 5% of the calendar-days, the resulting exposure for 

Hooker is 11 mrem/calendar-day.5

The assumption that the worker had his hands in contact with a slab of uranium rather than a 

wooden barrel containing slag with 0.2% to 2% U is claimant favorable. The wooden barrels 

would provide a significant reduction in beta dose compared to direct contact with a solid 

uranium object. The assumptions that the worker exposure is based on the median (64 mrad/hr), 

rather than the average or expected value (233 mrad/hr), and that barrel handling occurs on 5% 

of the work-days, are not claimant favorable. The average value of 233 mrad/hr is based on 

measurements that would not have the uncertainty suggested by assuming a lognormal 

distribution with a GSD of 5. 

 

As an alternative, NIOSH has suggested in its review of Petition SEC-00141 for Hooker that a 

value of 11.5 mrep/hr be used for shallow dose, based on measurements taken in 1948 at the top 

of a pile of C-liner slag at the St. Louis Airport Storage Site (NIOSH 2010). Estimates of 

exposure to the hands could then be based on the time spent per day with the hands in contact 

with the barrels of slag and the number of days per month that barrels were handled. However, 

as discussed above regarding photon exposure, the scientifically sound approach would be to 

calculate the shallow dose exposure using MicroShield or MCNP. 

Finding 6: NIOSH should consider whether use of shallow dose estimates based on slag 

sampling is a more plausible approach than pro-rating exposures from a large uranium object. 

Alternatively, NIOSH could consider using a conservative estimate of the concentration of 

uranium in the barrel, and take into consideration self-shielding and the shielding from the 

barrel wall using MicroShield or MCNP. 

 

3.5 REVIEW OF SECTION AA.6 “RESIDUAL CONTAMINATION” 

The residual period is assumed to run from January 15, 1946 through October 11, 1976. The end 

date was established based on a radiological survey conducted by the Oak Ridge National 

Laboratory for DOE showing that no elevated contamination levels were detected during the 

survey (ORNL 1977). 

 5

 Since the 5% exposure estimate was based on work-days rather than calendar-days, for logical 

consistency, the exposure should be increased by the ratio of 365 calendar-days/300 work days, which would 

increase the exposure to the hands to 13 mrem/calendar-day (219 mrem/day × 0.05 × 365/300). However, given the 

fact that the worker is assumed to have his hands in contact with uranium 50% of the time, this correction is 

inconsequential. 
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3.5.1 Estimate of Inhalation Quantity from Residual Contamination 

Per Table AA.1, NIOSH assumes an inhalation intake of 1 pCi/calendar-day for all workers 

during the residual period. NIOSH states the following in Section AA.6: 

The internal dose rates are based on the average air concentration during 

operations (from section C.4) assumed to deposit throughout an entire work year 

with no removal. This deposited contamination is assumed to resuspend with a 

resuspension factor of 1E-06 m-1. 

We presume that there is a typo in the above quotation and that the average air concentration 

during operations is obtained from Section AA.4, where the GM concentration is quoted as 

822 dpm/m3

. (Average air concentrations are not mentioned in Appendix AA.) This dust 

concentration assumes pure uranium when, in fact, the slag contains 0.2% U. At this dust level, 

the adjusted uranium concentration would be 1.64 dpm/m3

. When dust from the slag handling is 

deposited for an entire work year at a terminal settling velocity of 7.5E-04 m/s, the resulting 

surface concentration is 3.9E+04 dpm/m2 (0.002 × 822 dpm/m3 × 7.5E-04 m/s × 

3.15E+07 sec/yr). Based on the assumed resuspension factor of 1E-06/m, the resuspended dust 

concentration is 3.9E-02 dpm/m3 or 1.8E-02 pCi/m3. Using a breathing rate of 9.6 m3/8-hr work 

day, the intake is 0.17 pCi per work day or 0.13 pCi per calendar day (for a 48-hr work week). 

This value is lower by a factor of 8 than that cited in Table AA.1. 

We note that the intake would have been higher had a larger resuspension factor been used. 

SC&A has stated in several reports that a value of 1E-06/m is unrealistically low (e.g., SC&A 

2008). With a resuspension factor of 1E-03/m, the inhalation intake would be 130 pCi/calendarday. The approach taken in Appendix AA can, in principle, lead to claimant-favorable results, 

because the surface concentration is assumed to remain constant through the residual period. 

However, this is only true if the initial surface concentration and resuspension factors are 

properly justified. 

Finding 7: NIOSH should provide an example calculation showing how they arrived at an 

inhalation intake of 1 pCi/calendar-day. 

Finding 8: NIOSH should justify the use of a resuspension factor of 1E-06/m. 

We further note that the method used here of assuming a constant surface concentration during 

the residual period based on deposition during the final year of the operational period combined 

with a resuspension factor of 1E-06/m is not one of the seven methods proposed in ORAUTOTIB-0070 (ORAUT 2008). One method proposed in OTIB-0070 is to use the surface 

concentration at the end of the operation period, a resuspension factor of 1E-06/m and an 

assumed dust concentration decay rate of 1%/day. As pointed out by SC&A in its review of 

OTIB-0070, a resuspension factor of 1E-06/m is equivalent to a decay rate of 0.012%/day based 

on a room height of 5 m and one air change per hour (SC&A 2008). A decay rate of 1%/day is 

roughly equivalent to a resuspension factor of 1E-04/m. If one uses a higher resuspension factor, 

the initial dust concentration is higher, but the dust concentration falls much more rapidly over 

time. Figure 1 compares the dust concentration in the air at 100 days and 1,000 days after 
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cessation of operations for resuspension factors ranging from 1E-06/m to 1E-03/m. It can be 

seen that after 1,000 days, the dust concentration is greater for a resuspension factor of 1E-05/m 

than for values above and below. 

Figure 1. Effect of Resuspension Factors on Dust Concentrations 

However, a higher resuspension factor does not necessarily result in a higher integrated

inhalation intake. When sufficient time has elapsed, a worker will experience the same 

integrated intake regardless of the resuspension factor. For the case modeled here, the integrated 

intake is the same for resuspension factors of 1E-05, 1E-04, and 1E-03/m after 10 years. A 

considerably longer period is required to reach the same asymptotic value for a resuspension 

factor of 1E-06/m. 

As an alternative, NIOSH could have used an approach where the initial dust concentration was 

based on surface contamination at the end of operations and an appropriate resuspension factor, 

and assumed that this decayed exponentially to some value below the detection limit at the end 

of the residual period. 

Finding 9: NIOSH should justify that the approach taken to calculate inhalation exposures 

during the residual period is bounding, and take into consideration SC&A’s review of ORAUTOTIB-0070. 

3.5.2 Estimates of External Dose from Residual Contamination 

NIOSH used surface contamination exposures from Table 7.3 to estimate external exposures 

during the residual period. Thus, the median exposure for a scrap recovery operator standing on 

a contaminated surface is 0.376 mR/calendar-day based on a 48-hr work-week. As discussed in 

Section 3.4, this value is overstated by a factor of 100 and needs to be corrected. Even though 

the external exposure is trivial, NIOSH also needs to review the assumptions used in converting 

this exposure to pCi/calendar-day. 
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Finding 10: NIOSH needs to correct the calculation of external exposure during the residual 

period and revise the basis for converting this exposure to pCi/calendar-day.
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4.0 USE OF SURROGATE DATA 

In this section, we review the use of surrogate data in developing dose reconstruction guidance at 

Hooker, and how this usage comports with the surrogate data criteria recently approved by the 

ABRWH. As described in Section 3, the guidance for Hooker relies solely on TBD-6001, where 

surrogate data were used to calculate inhalation/ingestion intakes for both the operational and 

residual periods. In particular, NIOSH used data for scrap recovery operations based on 

measurements made by Christofano and Harris (1960) and summarized in Tables 8.23 and 8.24 

of TBD-6001. The selected data were for the average exposure of a furnace operator handling 

trays of scrap prior to 1952. No information is available about the number and distribution of 

samples used to calculate the average exposure. This measured average exposure 

(3,000 dpm/m3) was converted by NIOSH to a median exposure (822 dpm/m3), assuming a 

lognormal distribution with a GSD of 5. The use of surrogate data is evaluated below against the 

ABRWH’s criteria. It should be noted that the surrogate data criteria did not exist at the time 

that Appendix AA was written. 

(1) Hierarchy of Data. In accordance with this criterion, the usual data hierarchy should be 

followed; for example, individual monitoring data are preferable to workplace 

monitoring data. The surrogate data used at Hooker were both individual monitoring 

data and general area samples. In addition, the criterion further requires that surrogate 

data be used to replace available data only if the surrogate data have some advantages 

over available data. At Hooker, there were no available data, thereby necessitating the 

use of surrogate data. Adjustments must be made to the surrogate data to account for 

uncertainty. This was achieved at Hooker by assuming that workers were exposed to 

uranium dust, when in fact, their exposure was to slag containing a low percentage of 

uranium. Based on these considerations, we believe that the hierarchy of data criterion 

was satisfied. However, as discussed below, the approach used by NIOSH, though 

bounding, might not reflect plausible circumstances. 

(2) Exclusivity Constraints. This criterion requires that the use of surrogate data be 

stringently justified. Not only must the amount of surrogate data be considered, but also 

its quality and completeness. The Christofano and Harris (1960) dataset is 

comprehensive, covering the 60 complete evaluations made at 7 AEC uranium refining 

facilities over the 10-year period 1948 through 1957. The dataset included more than 

20,000 dust samples taken both from the operators’ breathing zone and the general work 

area. The measurements were made by AEC Health and Safety Laboratory (HASL), 

whose work was well-regarded. Unfortunately, the Christofano and Harris dataset does 

not provide information on the number and distribution of samples used to develop an 

average exposure. For example, as discussed above, the scrap recovery operator’s 

exposure is given as 3,000 dpm/m3

, but no information is available on the underlying 

data from which the average was calculated. While lacking in transparency, the dataset 

is based on a large amount of high quality data. On this basis, we believe the exclusivity 

constraints criterion is satisfied. 
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NOTICE:

(3) Site or Process Similarities. No AEC sites performed work identical to that at Hooker, 

i.e., leaching of uranium-bearing slag with HCl. However, as described in Section 3.3 

above, some sites did perform acid leaching of ore and/or concentrates, which involved 

processing steps similar to those at Hooker, including drum handling, acid digestion, and 

filtration. Instead of choosing dust sampling results from these operations, NIOSH 

chose a more conservative and claimant-favorable approach to bounding worker 

exposures by selection of a furnace operator involved in scrap recovery as the basis for 

dose reconstruction. Thus, to insure that inhalation/ingestion exposures at Hooker were 

bounded, NIOSH selected data from a process that generated higher dust levels than the 

actual Hooker process. Such an approach is certainly claimant favorable, but it does 

raise question regarding process similarities and plausible circumstances. 

(4) Temporal Considerations. It is desirable that surrogate data be obtained during the same 

general period for which doses are to be reconstructed. NIOSH used data prior to 1952 

(TBD-6001, Table 8.23) to reconstruct doses for the period July 11, 1944, through 

January 15, 1946. We believe that these periods are reasonably contemporaneous and 

that this criterion is satisfied. 

 

(5) Plausibility. This criterion addresses the reasonableness of the assumptions made, in 

terms of both scientific plausibility and workplace plausibility. Judging plausibility in 

the case of a bounding calculation such as at Hooker is highly subjective. On the one 

hand, selection of the bounding approach must not strain credulity to the point of being 

impossible. (Obviously, almost anything can be bounded.) On the other hand, the 

selected approach must insure that the results are indeed bounding to protect the 

claimant. At Hooker, NIOSH selected an aspect of the uranium scrap recovery operation 

that involved the highest exposure (furnace operator handling trays of uranium oxide) 

and applied it to processing slag—a product with a low uranium content (0.2%). We 

believe that information is available in TBD-6001 on processes that more closely 

approximate the operations at Hooker. Use of such data should be considered by 

NIOSH to better demonstrate the plausibility of the dose reconstruction guidance. We 

also note that in its review of Petition SEC-00141 (NIOSH 2010), NIOSH utilized data 

on C-2 slag handling at several AEC sites. Use of these data could also lead to more 

plausible guidance than use of the scrap recovery data from TBD-6001. 

 

External operational exposures in Appendix AA and TBD-6001 from penetrating radiation 

during handling uranium-bearing materials were based on MicroShield calculations. External 

operational exposures from non-penetrating radiation were based on measured values taken from 

natural uranium slabs. As such, these exposures did not involve use of surrogate data.
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5.0 SUMMARY, CONCLUSIONS, AND INITIAL IMPRESSIONS 

REGARDING THE SEC PETITION AND EVLAUATION REPORT 

Appendix AA of Battelle-TBD-6001 provides guidance for the reconstruction of potential 

occupational exposures to Hooker Chemical Company workers from medical x-rays and internal, 

as well as external, sources during the 18-month operational period of July 11, 1946, through 

January 15, 1946. Thereafter, Appendix AA also provides guidance for the reconstruction of 

internal and external exposures associated with residual contamination through October 11, 

1976. 

Because worker-specific monitoring records for Hooker personnel are unavailable, NIOSH 

intends to assign default doses for occupational medical, external, and internal exposures during 

facility operation, as well as from residual contamination from 1946 through 1976. In total, our 

review identified 3 observations and 10 findings. A common element in our findings is that the 

default values contained in Tables AA.1 and AA.3 appear to reflect a combination of 

undocumented assumptions, errors in the underlying source document TBD-6001, and lack of 

traceability of some of the data. Attempts by SC&A to duplicate/validate NIOSH’s default 

values were only partially successful. 

Even though many of the models and assumptions and much of the data used to construct the coworker model appear to be bounding, they represent circumstances that are not plausible for 

Hooker and for which a site-specific analysis needs to be performed. 

In the process of reviewing Appendix AA, SC&A briefly examined the NIOSH report reviewing 

Petition SEC-00141. This review was only cursory, but a few observations are noted here: 

 There is considerable confusion about the extent to which activities were conducted 

indoors versus outdoors. Despite recollections of workers interviewed during preparation 

of the Petition Evaluation Report, the Completion Report – Construction of the Hooker 

Electrochemical Company P-45 Plant (Dowling 1944) states that agitated tanks, plate 

and frame filter press, bucket elevator, pumps, motors and auxiliary equipment were 

housed in a specially constructed cinder block building. Therefore, it should be 

concluded that most of the processing was conducted indoors. 

 In documenting its ability to adequately reconstruct internal exposures, NIOSH sited dust 

levels associated with slag handling at Fernald, Mallinckrodt and Electro-Met. Use of 

actual slag-handling data is superior to using generic scrap recovery data from TBD-6001. 

The highest average dust concentration observed during slag handling was 456 dpm/m3

(at Electro-Met), while the average dust concentration used to develop Appendix AA 

guidance was 3,000 dpm/m3. While clearly supporting the NIOSH contention that the 

approach taken in Appendix AA is claimant favorable, it also supports SC&A’s concern 

that Appendix AA may be overly conservative. 

 NIOSH used a similar approach to documenting external exposure in the Hooker Petition 

Evaluation Report, namely, use of measurements taken directly from slag. A photon dose 

of 1.6 mrep/hr was measured chest- high at the top of a large slag pile (Caplan 1949). In 
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NOTICE:

Appendix AA, NIOSH calculated photon (plus Bremstrahhlung) exposure of 0.3 mR/hr 

at 100 cm from a 55-gallon drum. It is difficult to compare the two approaches. As 

noted above, a preferable approach would be to calculate the external exposure from 

barrels containing slag with either MicroShield or MCNP. 

Before concluding, we would like to point out that it is difficult to provide our initial impressions 

regarding possible SEC issues, because the site profile is based primarily on surrogate data. A 

typical SEC petition/Evaluation Report review focuses on data completeness and adequacy, as 

collected and used at the facility under review. This is not possible here, because the dose 

reconstruction methods employed surrogate data. Hence, a review of the SEC petition and 

Evaluation Report will need to focus on surrogate data issues. 
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6.0 REFERENCES 

Allen 2010. E-mail correspondence from D. Allen (NIOSH) to W.C. Thurber (SC&A) 

responding to questions on Hooker. June 16, 2010. 

Battelle-TBD-6001. Site Profiles for Atomic Weapons Employers the Refine Uranium and 

Thorium. Revision F0, December 13, 2006. 

Battelle-TBD-6001, Appendix AA. 2008. Site Profiles for Atomic Weapons Employers the 

Refine Uranium and Thorium – Appendix AA Hooker Electrochemical Company. June 15, 2007. 

Caplan 1949. Health Problems at the Airport Properties, correspondence to H. E. Thayer, 

Mallinckrodt Chemical Works, from K. J. Caplan, Mallinckrodt Chemical Works; August 11, 1949; 

SRDB Ref ID: 11193. 

Christofano E. and W.B. Harris, 1960. The Industrial Hygiene of Uranium Refining. Env. 

Health 1(5):74-96. 

DOE 1977. Formerly Utilized MED/AEC Sites Remedial Action Program, Radiological Survey 

of the Hooker Chemical Company, Niagara Falls, New York, Final Report. U.S. Department of 

Energy, Washington, DC. Ref ID 10797. 

DOE 1985. Formerly Utilized Sites Remedial Action Report Elimination Report for Occidental 

Chemical Corporation (Former Hooker Electrochemical Company) Niagara Falls, New York, 

U.S. Department of Energy, Washington, DC. Ref ID 11002, p. 59. 

DOE 2004. Guide of Good Practices for Occupational Radiological Protection in Uranium 

Facilities. DOE-STD-1136-2004. December. 

Dowling, Francis A., c. 1944. Completion Report, Construction of Hooker Electrochemical 

Company P-45 Plant. Contract No. W-7405-ENG-28. Tonawanda Area-Manhattan District. 

Ref ID 11002, pp. 102–112. 

Johnson, E.R., R.L. Doyle, J.R. Coleman, A.B. Kreuzmann, E.O. Rutenkroger, and W.H. 

Malotte, 1954. Uranium Recovery from UF4 Bomb Reduction Wastes. AECD-3703. National 

Lead Company of Ohio. 

MED 1944. Medical Section – Manhattan District, Data Sheets for Industrial Hazard Rating. 

Manhattan Engineer District. Ref ID 16323, pp. 29-30. 

NIOSH 2010. SEC Petition Evaluation Report, Petition SEC-00141: Hooker Electrochemical. 

May 3, 2010. 

ORAUT 2005. Dose Reconstruction from Occupationally Related Diagnostic X-ray Procedures, 

ORAUT-OTIB-0006, Rev. 03, Oak Ridge Associated Universities Team: Cincinnati, Ohio. 

December 21, 2005. 
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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. 

NOTICE:

ORAUT 2008. Dose Reconstruction During Residual Radioactivity Periods at Atomic Weapons 

Employer Facilities, ORAUT-OTIB-0070, Rev. 00. Oak Ridge Associated Universities Team: 

Cincinnati, Ohio. March 10, 2008. 

ORNL 1977. Radiological Survey of the Hooker Chemical Company, Niagara Falls NY, 

Formerly Utilized MED/AEC Sites Remedial Action Program. DOE/EV-0005. Oak Ridge 

National Laboratory. January 1977. SRDB Ref ID 10797. 

SC&A 2008. Review of ORAUT-OTIB-0070: Dose Reconstruction During Residual 

Radioactivity Periods at Atomic Weapons Employer Facilities. SCA-TR-TASK3-0009, 

Revision 0. SC&A, Inc.: Vienna, Virginia. 

SC&A 2010. Review of NIOSH Petition Evaluation Report for Petition SEC-00136 Dated July 

21, 2009, Electro Metallurgical Corporation. Rev. 0. Contract No. 200-2009-28555, SCA-TRSEC2010-0010. SC&A, Inc.: Vienna, Virginia. April 2010. 

Strom, D.F. 2007. Default Assumptions and Methods for Atomic Weapons Employer Dose 

Reconstructions. Battelle-TIB-5000, Rev. 00, Effective date: April 2, 2007. 

Young, C.D. 1985. Letter from Charles D. Young (Aerospace Corporation) to Arthur Whitman 

(DOE), Update of Responses to Hooker (OCC) Interrogatories. February 28, 1985. Ref ID 

11002, pp. 63-71.
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ATTACHMENT 1: ISSUES MATRIX FOR TBD-6001 

AS OF JUNE 14, 2010 

TBD-6001 Issues Matrix 

Finding or 

Observation SC&A TBD Reviewa NIOSH Initial Response SC&A Comments on 

NIOSH Response 

Finding 1 It is not possible to judge 

whether the basic approach to 

developing inhalation doses in 

TBD-6001 is claimant 

favorable, based on the 

information presented in that 

document. However, based on 

analyses presented in this 

review, it appears that the 

average inhalation doses used in 

TBD-6001 are not claimant 

favorable, particularly for the 

period prior to 1948 (SC&A 

2008, Section 8.1). 

Finding 2 TBD-6001 oversimplifies the 

process descriptions from 

Christofano and Harris (1960) 

and, as a result, may have 

missed or understated 

significant pathways for 

external and internal exposure 

(SC&A 2008, Section 4.0). 

Finding 3 The approach used in TBD6001 to calculate the 

contribution to external 

exposure of contaminated dust 

settled on workplace surfaces is 

not appropriate. SC&A 

addressed the same issue in its 

review of TBD-6000 (SC&A 

2007, Item 5). (See Section 3.1 

in SC&A 2008 for basis of 

Finding 3.) 

This issue has been 

resolved as part of the 

TBD-6000 Issue 

Resolution Process, based 

on the Battelle-TBD-6000 

Issue 5 White Paper 

(Allen 2009). NIOSH 

demonstrated, based on 

data from Adley et al. 

1952, that the median 

settling rate was 0.00023 

m/s, as compared to 

0.00075 m/s assumed in 

TBD-6000 and TBD6001. The lower settling 

rate reduces external 

exposure from surface 

contamination and 

resuspended 

contamination. The 

assumption of a 7-day 

deposition period 

understates the expected 

total deposition, but the 

impact on external dose is 

trivial. 

It would be helpful if 

NIOSH indicated why a 

deposition period of 7 

days was used for 

calculating external 

dose from contaminated 

surfaces in TBD-6000 

(Section 6.1.2), while a 

deposition period was 

used in TBD-6001 

(Section 7.1.2). 

Finding 4 Summary Tables 7.1 and 7.3 in 

Section 7 of TBD-6001 that 

address external exposures 

require additional elaboration to 

understand the sources of the 

contained data and how the data 
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TBD-6001 Issues Matrix 

Finding or 

Observation SC&A TBD Reviewa

 NIOSH Initial Response SC&A Comments on 

NIOSH Response 

were derived (SC&A 2008, 

Sections 7.1 and 7.3). 

Finding 5 The approach taken by NIOSH 

to develop year-specific 

correction factors to inhalation 

doses does not appear to be 

claimant favorable. Doses in 

the early years may be 

understated. (SC&A 2008, 

Section 8.3) 

Finding 6 NIOSH did not consider radon 

exposures in developing 

inhalation exposure rates. Since 

pitchblende ore contains 

significant quantities of Ra-226 

and its progeny, this omission 

significantly understates 

inhalation exposure rates for 

workers involved with 

operations at the front end (ore 

processing) of the refining 

process (SC&A 2008, Section 

3.2).

Observation 1 NIOSH states in Section 1 that 

the report provides the technical 

basis for reconstructing doses 

for AWE sites that refined 

uranium under government 

contract during the period 

1942–1958; however, no basis 

is provided for selecting 1942–

1958 as the relevant time 

period. We also note that 

NIOSH refers elsewhere to 

1944 as the start date (pg. 4, 

second paragraph). NIOSH 

should document the basis for 

the dates and correct any 

inconsistencies. 

Observation 2 As noted in Section 2.0 of TBD6001, Christofano and Harris 

(1960) do not present 

information on exposures from 

the solvent extraction unit 

operation. NIOSH notes in 

Section 8.2.2 that the air 

concentration data for solvent 

extraction are under 

development. NIOSH should 

provide the appropriate data. 

Observation 3 TBD-6001 should address 

possible exposures to Th-230 

and Ra-226 for workers 

handling ore (SC&A 2008, 

Section 3.2). 
Effective Date: 

September 9, 2010

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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. 

TBD-6001 Issues Matrix 

Finding or 

Observation SC&A TBD Reviewa

 NIOSH Initial Response SC&A Comments on 

NIOSH Response 

Observation 4 TBD-6001 also does not address 

exposures to enriched uranium 

(EU) or recycled uranium (RU). 

In light of this, Section 1 of the 

report, titled “Purpose and 

Scope,” should make it clear 

that this document should only 

be used for workers involved in 

the processing of uranium ores 

and concentrates, and that it 

does not provide direction 

regarding exposures to workers 

who might have handled EU, 

RU, or ores containing Th-232 

(SC&A 2008, Section 3.2). 

Observation 5 Any use of a default air 

concentration for nonoperational areas should provide 

some guidance as to what 

should be considered “nonoperational areas of the plant.” 

Use of a value of 7 dpm/m3 

would not be appropriate for all 

types of non-operational 

locations (SC&A 2008, Section 

6.1). 

Observation 6 No information is provided as to 

how doses are apportioned to 

laborers, supervisors, and 

clerical staff in Table 7.3 of 

TBD-6001 (SC&A 2008, 

Section 7.5). 

Observation 7 It should be noted that in several 

of the TBD-6001 lognormal 

tables in Section 8, the reported 

GSD is less than 1, although the 

GSD for a lognormal 

distribution must be greater than 

1. Hence, there appears to be an 

error here that needs to be 

corrected (SC&A 2008, Section 

8.1). 

Observation 8 SC&A provided a list of minor 

clarifications and corrections 

that should be made to TBD6001 (SC&A 2008, Section 9). 

Observation 9 Table 8.3 lists the GSD of the 

daily weighted average for ore 

as 4.939. Although not stated in 

TBD-6001, we presume that the 

GSD is calculated based on 

equations 3 and 10 of Strom 

2007. Using these equations, 

we calculate the GSD to be 

3.539. NIOSH should confirm 

what the correct value is for the 

GSD, and document the 

procedures used to calculate 
Effective Date: 

September 9, 2010

Revision No. 

 0 (Draft)

Document No. 

SCA-TR-SP2010-0034

Page No. 

 27 of 28

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. 

TBD-6001 Issues Matrix 

Finding or 

Observation SC&A TBD Reviewa

 NIOSH Initial Response SC&A Comments on 

NIOSH Response 

median and GSD values in 

Section 8.0 of TBD-6001. 

Observation 10 NIOSH states in Section 3.5 of 

TBD-6001 that, “The dose 

reconstructor should use the 

default values shown above. 

The default values of ICRP-66 

(ICRP 1994) should be used.” 

This is very confusing. In one 

sentence, the dose reconstructor 

is advised to use Table 3.12 and 

in the next, he is advised to use 

ICRP-66. In addition to 

confusing instructions, we 

believe that the correct 

reference should be ICRP-68, 

Annexe F, Table F.1. There are 

similar problems with the 

introductory material at the 

beginning of Section 8.0 in 

TBD-6001. 

Observation 11 While the assumption of a 5-μm 

AMAD is often used for 

calculating inhalation doses, it 

is of questionable relevance 

when calculating surface 

contamination levels (SC&A 

2008, Section 6.1, p. 20). 

Observation 12 In its review of TBD-6000, 

SC&A raised some concerns 

about the use of an air 

concentration of 7 dpm/m3

 for 

non-operational areas of a plant 

(SC&A 2007, Section 5). We 

further note here that exposures 

to workers in non-operational 

areas may be higher than that 

(SC&A 2008, Section 6.1, p. 

20). 

Observation 13 NIOSH should explain why the 

calculations discussed in 

Section 8.4.2 are not done on 

the same basis as those in 

Section 3.4.2 (SC&A 2008, 

Section 8.2, p. 36). 

a – SC&A 2008. Draft Review of Battelle-TBD-6001, Site Profiles for Atomic Weapons Employers That Refined 

Uranium and Thorium, Revision FO Dated December 13, 2006, Contract No. 200-2004-03805, Task Order No. 1, 

SCA-TR-TASK1-0026. 

Note: The “Observations” tabulated above are based on comments made by SC&A in the text of SC&A 2008, but 

not specifically delineated as “Observations.”

Other References: 

Adley, F.E., Gill, W.E., and Scott, R.H., 1952. Study of Atmospheric Contamination in the Metal 

Melt Building. U.S. Atomic Energy Commission, HW-23352 (rev.), April 4, 1952. 
Effective Date: 

September 9, 2010

Revision No. 

 0 (Draft)

Document No. 

SCA-TR-SP2010-0034

Page No. 

 28 of 28

 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. 

NOTICE:

Allen 2009. Battelle-TBD-6000 Issue 5 White Paper, Comparison to Adley Contamination Data. 

October 9, 2009. 

Christofano E. and W.B. Harris. 1960. The Industrial Hygiene of Uranium Refining. Env Health 

1(5):74-96. 

ICRP (International Commission on Radiation Protection) 1994. Human Respiratory Tract 

Model for Radiological Protection. Publication 66. Ann. ICRP 24(3-1). Oxford: Pergamon 

Press. 

ICRP (International Commission on Radiological Protection) 1994. Dose Coefficients for 

Intakes of Radionuclides by Workers, Publication 68, Pergamon Press, Oxford, England. 

SC&A 2007. Draft Review of Battelle-TBD-6000, Site Profiles for Atomic Weapons Employers 

that Worked Uranium and Thorium Metal, Contract No. 200-2004-03805, Task Order No. 3. 

SC&A, Inc., Vienna, Virginia. September 14, 2007. 

SC&A 2008. Draft Review of Battelle-TBD-6001, Site Profiles for Atomic Weapons Employers 

That Refined Uranium And Thorium, Revision FO Dated December 13, 2006, SCA-TR-TASK1-

0026, Rev. 0. SC&A, Inc., Vienna, Virginia, and Saliant, Inc., Jefferson, Maryland. February 26, 

2008. 

Strom, Daniel F. 2007. Default Assumptions and Methods for Atomic Weapons Employer Dose 

Reconstructions. Battelle-TIB-5000, Rev. 00, Effective date: April 2, 2007.