SCA-TR-TASK3-0012, Rev. 0 

DRAFT 

NATIONAL INSTITUTE FOR 

OCCUPATIONAL SAFETY AND HEALTH 

ADVISORY BOARD ON RADIATION AND WORKER HEALTH 

REVIEW OF NIOSH/ORAUT PROCEDURES AND METHODS 

USED FOR DOSE RECONSTRUCTION 

A PRELIMINARY REVIEW OF NIOSH’S PROGRAM EVALUATION REPORT 

OCAS-PER-020, “BLOCKSON TBD REVISION” 

Contract No. 200-2009-28555 

SCA-TR-TASK3-0012, Rev. 0 

Prepared by 

Hans Behling, PhD 

S. Cohen & Associates 

1608 Spring Hill Road, Suite 400 

Vienna, VA 22182 

March 2009 

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.

 
Effective Date: 

March 23, 2009 

Revision No. 

0

Document No. 

SCA-TR-TASK3-0012

Page No. 

2 of 25

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.

Document No. 

SCA-TR-TASK3-0012 

Effective Date: 

Draft — March 23, 2009 

S. COHEN & ASSOCIATES: 

Technical Support for the Advisory Board on

Radiation & Worker Health Review of 

NIOSH Dose Reconstruction Program Revision No. 0 – (Draft) 

Task 3: Review of NIOSH/ORAUT Procedures 

And Methods Used For Dose Reconstruction 

A PRELIMINARY REVIEW OF NIOSH’S 

PROGRAM EVALUATION REPORT 

OCAS-PER-020, “BLOCKSON TBD 

REVISION” 

Page 2 of 25 

Document Reviewer: 

________________________ Date: ___________ 

U. Hans Behling, PhD, MPH 

Project Manager: 

________________________ Date: ___________ 

John Mauro, PhD, CHP 

Supersedes: 

N/A 

Record of Revisions 

Revision 

Number 

Effective 

Date Description of Revision 

0 (Draft) 03/23/2009 Initial issue 

01/13/2010 Document cleared as written for potential Privacy Act-protected information. 

Disclaimer updated and “Record of Revisions” table added to page 2. 
Effective Date: 

March 23, 2009 

Revision No. 

0

Document No. 

SCA-TR-TASK3-0012

Page No. 

3 of 25

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.

TABLE OF CONTENTS 

Executive Summary.........................................................................................................................5 

1.0 Statement of Purpose ...........................................................................................................7 

2.0

........................................................................................................................................8 

Subtask 1: Identify the Circumstances that Necessitated the Need for OCAS-PER020

3.0

........................................................................10 

Subtask 2: Assess NIOSH’s Evaluation/Characterization of the Issues and Their 

Potential Impacts on Dose Reconstruction

3.1 Site Description and Operational History..............................................................10 

3.2 Inclusion of Non-Uranium Activities in Dose Reconstruction..............................10 

3.3 Revised Intakes for Uranium Extraction in Building 55 .......................................11 

3.4 Revision to Radon Exposure Estimates.................................................................13 

3.5 Changes Associated with External Exposure ........................................................14 

3.6 Revisions to Doses from Residual Contamination ................................................14 

4.0 Subtask 3: Assess NIOSH’s Specific Methods for Corrective Action .............................15 

4.1 General Comments.................................................................................................15 

4.2

........................................................................15 

Issue #1: NIOSH’s Assigned Solubility Class Type M for Uranium and Its 

Use for Converting Urine Excretion Data to Inhalation Quantities for 

Building 55 May Be Inappropriate

4.3

..........................................................................................................19 

Issue #2: NIOSH’s Assigned f Value of 0.02 for Uranium and Its Use for 

Converting Urine Excretion Data to Inhalation/Ingestion Quantities May Be 

Inappropriate

1

4.4

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

Issue #3: The Assigned Radon Exposure Value of 0.112 WLM/year as a 

Bounding Value for Blockson May Be Inappropriate

5.0

...........................................................................................................................22 

Subtask 4: Evaluate the PER’s Stated Approach for Identifying the Universe of 

Potentially Affected Dose Reconstructions; and Assess the Criteria by Which a 

Subset of Potentially Affected Dose Reconstructions Was Selected for Reevaluation

6.0 Subtask 5: Conduct Audits of Dose Reconstructions Affected by OCAS-PER-020........23 

7.0 References..........................................................................................................................24 
Effective Date: 

March 23, 2009 

Revision No. 

0

Document No. 

SCA-TR-TASK3-0012

Page No. 

4 of 25

 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:

LIST OF TABLES 

Table 1. Inhalation and Ingestion Intakes for Calcining...............................................................11 

Table 2. Inhalation Rate for Operations Cited in OCAS-TKBS-0002 Revision 0 .......................12 

Table 3. Ingestion Rate for Operations Cited in OCAS-TKBS-0002 Revision 0 ........................12 

Table 4. Inhalation Rate for Building 551,2,3 .................................................................................12 

Table 5. Ingestion Rate for Building 551,2 ....................................................................................13 

Table 6. Radon Exposures Cited in OCAS-TKBS-0002 Revision 00..........................................13 

Table 7. Radon Exposures Cited in OCAS-TKBS-0002 Revision 01..........................................14 

Table 8. Airborne Uranium Concentrations During Packaging Operations of Yellowcake.........18 

LIST OF FIGURES 

Figure 1. Comparison of Rn Concentrations Using SC&A and NIOSH Parameters 222 ...............21 
Effective Date: 

March 23, 2009 

Revision No. 

0

Document No. 

SCA-TR-TASK3-0012

Page No. 

5 of 25

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.

 

EXECUTIVE SUMMARY 

Under the existing Task 3 project, SC&A has been tasked by the Advisory Board on Radiation 

and Worker Health (Advisory Board) to conduct an audit of the Program Evaluation Report 

(PER) OCAS-PER-020, which was prompted by extensive revisions to OCAS-TKBS-0002, 

Technical Basis Document for Atomic Energy Operations at Blockson Chemical Company, 

Joliet, Illinois, Revision 0. 

Because revisions to the Blockson technical basis document (TBD) impacted dose reconstruction 

methodology for nearly all exposure pathways, NIOSH elected to reassess all 91 Blockson 

Chemical Company claims, which had yielded probability of causation (POC) values less than 

50% under previous dose reconstructions. SC&A concurs that the selection criteria used by 

NIOSH do, in fact, encompass the universe of potentially affected dose reconstructions. 

As a result of the reassessment that was prompted by OCAS-PER-020, revised dose estimates for 

32 claims yielded POC values 50% and were, therefore, compensable. For the remaining 59 

claims, revised tissue doses increased significantly, but resulted in POC values that were, 

nevertheless, below 50%. SC&A believes that the PER is being implemented appropriately, 

given the changes to the TBD. However, given that there might be a need for additional changes 

to the TBD (in light of issues under active consideration by the Blockson work group),* it is 

possible that additional revisions to the PER for Blockson might be needed in the future. 

As part of our audit, SC&A critically reviewed all revisions to the Blockson TBD for technical 

merit and/or claimant favorability. Of particular importance to claimant favorability are 

instances in which dose reconstruction could not be supported by claimant-specific or sitespecific data, but required the use of default values, assumptions, or surrogate data. 

Our review of OCAS-PER-020 and OCAS-TKBS-0002, Revision 01, identified the following 

three potential issues that were not adequately addressed in OCAS-PER-020: 

(1) For Building 55 workers, exposure to uranium may have involved low solubility or 

Type S uranium compound(s). 

(2) Equally, a lower solubility uranium material, if ingested, would imply the assumption of 

a lower f1 value. 

(3) Estimates of indoor radon concentrations employed surrogate data that are considered 

inappropriate and resulted in low exposure values. 

As discussed in Section 4 of this report, these three unresolved issues have the potential for 

significantly affecting organ doses that include the 59 claims that presently remain below a POC 

value of 50% under OCAS-PER-020. 

*

 These issues include (1) solubility class Type S for U, (2) f1 value of 0.002 for U, and (3) higher radon 

levels in Building 40. 
Effective Date: 

March 23, 2009 

Revision No. 

0

Document No. 

SCA-TR-TASK3-0012

Page No. 

6 of 25

 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:

Finally, it should also be mentioned that on November 11, 2007, NIOSH published Revision 02 

of OCAS-TKBS-0002, which included (1) changes to footnotes in Table 4a and Table 12a that 

now require consideration of Type M and Type S thorium in Building 55, (2) correction of errors 

contained in Table 7 and the resulting graph in Figure 6, and (3) correction to the liver dose in 

Table 8. 
Effective Date: 

March 23, 2009 

Revision No. 

0

Document No. 

SCA-TR-TASK3-0012

Page No. 

7 of 25

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.

1.0 STATEMENT OF PURPOSE 

To support dose reconstruction, the National Institute for Occupational Safety and Health 

(NIOSH) and the Oak Ridge Associated Universities Team (ORAUT) have assembled a large 

body of guidance documents, workbooks, computer codes, and tools. In recognition of the fact 

that all of these supporting elements in dose reconstruction may be subject to revisions, 

provisions exist for evaluating the effect of such programmatic changes on the outcome of 

previously completed dose reconstructions. Such revisions may be prompted by document 

revisions due to new information, misinterpretation of guidance, changes in policy, and/or 

programmatic improvements. 

The process for evaluating potential impacts of programmatic changes on previously completed 

dose reconstructions has been proceduralized in OCAS-PR-008, Preparation of Program 

Evaluation Reports and Program Evaluation Plans, Revision 2, dated December 6, 2006. This 

procedure describes the format and methodology to be employed in preparing a Program 

Evaluation Report (PER) and a Program Evaluation Plan (PEP). 

A PER provides a critical evaluation of the effect(s) that a given issue/programmatic change may 

have on previously completed dose reconstructions. A PER includes a qualitative and, in some 

cases, quantitative assessment of potential impacts. Most important in this assessment is the 

potential impacts on the probability of causation (POC) of previously completed dose 

reconstructions with POCs of <50%. 

As needed, a PEP may be issued that serves as a formal notification of an impending PER. The 

PEP provides a preliminary description of the issue(s) that will be addressed in the PER, and 

summarizes the likely scope of the effort required to complete the PER. 

Under the existing project, SC&A has been tasked by the Advisory Board to conduct an audit of 

OCAS-PER-020, Blockson TBD Revision. In conducting the PER review, SC&A is committed 

to perform five subtasks, each of which is discussed in this report. 
Effective Date: 

March 23, 2009 

Revision No. 

0

Document No. 

SCA-TR-TASK3-0012

Page No. 

8 of 25

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.

2.0 SUBTASK 1: IDENTIFY THE CIRCUMSTANCES THAT 

NECESSITATED THE NEED FOR OCAS-PER-020 

On September 11, 2006, NIOSH issued a technical basis document (TBD) entitled, Technical 

Basis Document for Atomic Energy Operations at Blockson Chemical Company, Joliet, Illinois,

OCAS-TKBS-0002, Revision No. 0. 

Following initial reviews of this TBD, NIOSH informed the Advisory Board on January 8, 2007, 

that NIOSH OCAS was withdrawing OCAS-TKBS-0002 for further evaluation and revision. A 

series of draft revisions identified as Revision 01-A, Revision 01-B, and Revision 01-C were 

issued on March 30, 2007; April 11, 2007; and June 14, 2007; respectively. These draft 

revisions addressed internal as well as external review comments, and resulted in expanded site 

descriptions, new radiological data, and the addition of several radionuclides. 

On June 20, 2007, NIOSH issued Revision 01 of OCAS-TKBS-0002, which formalized the 

acknowledged draft revisions and concluded that said changes “. . . revised internal and external 

dose modeling . . . [that] result in an increase of dose, and a PER is required.” 

On July 31, 2007, NIOSH issued OCAS-PER-020. Because PER-020 consists of three very 

brief sections (contained on a single page), it is introduced in this report as Exhibit 1. 
Effective Date: 

March 23, 2009 

Revision No. 

0

Document No. 

SCA-TR-TASK3-0012

Page No. 

9 of 25

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.

EXHIBIT #1 – OCAS-PER-020 
Effective Date: 

March 23, 2009 

Revision No. 

0

Document No. 

SCA-TR-TASK3-0012

Page No. 

10 of 25

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.

3.0 SUBTASK 2: ASSESS NIOSH’S 

EVALUATION/CHARACTERIZATION OF THE ISSUES AND 

THEIR POTENTIAL IMPACTS ON DOSE RECONSTRUCTION 

Under Subtask 2, SC&A is to ensure that PER issue(s) is/are fully addressed and characterized in 

the PER. 

Section 2.0 of PER-020 (see Exhibit #1) briefly states that revisions incorporated in Revision 01 

of OCAS-TKBS-0002 will impact several exposure pathways and are likely to increase radiation 

dose estimates, and that the magnitude of revised dose estimates will vary among the types of 

cancers that represent individual claimants. Correspondingly, NIOSH concluded that “. . . It is, 

therefore, not possible to determine the effect on the Probability of Causation (POC) without a 

new dose reconstruction.” 

Due to the fact that OCAS-PER-020 does not identify or characterize specific revisions to 

OCAS-TKBS-0002 that are likely to affect dose estimates and POC values, a brief summary of 

revisions salient to OCAS-PER-020 is presented below. 

3.1 SITE DESCRIPTION AND OPERATIONAL HISTORY 

Critically new information added to Blockson’s site description and operational history includes 

non-uranium work activities inclusive of those in Building 40. This facility received calcined 

phosphate feed, which was oxidized with chlorine and digested with sulfuric acid. This 

produced phosphogypsum in Building 40 and phosphoric acid, which was transferred as feed 

material to Building 55, where uranium was extracted under contract to the Atomic Energy 

Commission (AEC). 

While certain radionuclides originally contained in calcined phosphate rock are predominantly 

retained in the phosphoric acid along with uranium, select other radionuclides do not report to 

the acid feed, but are retained in the phosphogypsum produced in Building 40. Key among the 

radionuclides with potential radiological impacts to workers in Building 40 are polonium, 

radium, and radon (and associated progeny). 

3.2 INCLUSION OF NON-URANIUM ACTIVITIES IN DOSE RECONSTRUCTION 

For non-uranium activities (that include workers assigned to Building 40), NIOSH selected the 

calciner on the assumption that this facility/operation was likely to have subjected non-uranium 

workers to bounding intakes of radioactivity. The calciner was a large outdoor furnace used to 

heat phosphate rock in order to degrade organics in preparation of acid digestion in Building 40. 

Inhalation intakes for non-uranium workers are based on surrogate-facility air sampling data, 

which identified a peak dust loading of 50.4 mg/m3

 in the vicinity of a phosphate rock calciner. 

Applying a 0.014% uranium content in phosphate rock, NIOSH derived daily inhalation and 

ingestion activity values for 12 radionuclides, as given in Table 1 below, along with their 

recommended solubility classes. 
Effective Date: 

March 23, 2009 

Revision No. 

0

Document No. 

SCA-TR-TASK3-0012

Page No. 

11 of 25

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.

Table 1. Inhalation and Ingestion Intakes for Calcining 

Radionuclides Inhalation (pCi/day) Ingestion (pCi/day) 

U-2381; Th-2301; U-2341, Ra-2262; Pb-2103 16 0.47 

Po-2104 160 4.7 

Th-2311; Pa-2311; Ac-2271 0.73 0.021 

Th-2321; Ra-2282; Th-2281 0.52 0.016 1

 Solubility Class 1 = Type M or S (based on claimant favorability) 

2

 Solubility Class 2 = Type M 

3

 Solubility Class 2 = Type F 

4

 Solubility Class 2 = Type F or M (based on claimant favorability) 

3.3 REVISED INTAKES FOR URANIUM EXTRACTION IN BUILDING 55 

Internal exposure to workers in Building 55 from either inhalation or ingestion in OCAS-TKBS0002, Revision 0, Revision 01, and Revision 02, are all based on the results of 122 urinalyses 

representing “20” workers. The analyses for uranium was performed by fluorometry and defined 

in units of μg/liter. 

In order to derive daily inhalation quantities from urine data, NIOSH assumed the solubility 

class Type M for uranium, which at the 95th percentile level yielded (1) an inhalation intake of 

82 pCi/day total uranium (or 41 pCi/day for U-238 and 41 pCi/day for U-234) for production 

workers; and (2) 26 pCi/day total uranium (or 13 pCi/day U-238 and 13 pCi/day U-234) for 

administrative personnel. 

Alternatively, NIOSH converted urine data to a daily ingestion exposure by means of a f1 value 

of 0.02, which yielded ingestion intakes of 278 pCi/day total uranium for production workers and 

82 pCi/day for administrative workers. 

Changes incorporated in Revision 01 and Revision 02 to OCAS-TKBS-0002 that are relevant to 

PER-020 include the addition of the following radionuclides; Th-230, Pb-210, Po-210, Th-231, 

Pa-231, Ac-227, Ra-226, and Ra-228. 

For ease of comparison, original intakes derived for inhalation and ingestion as cited in 

Revision 0 are reproduced below in Table 2 and Table 3. These should be compared to the 

revised values shown in Table 4 and Table 5. 
Effective Date: 

March 23, 2009 

Revision No. 

0

Document No. 

SCA-TR-TASK3-0012

Page No. 

12 of 25

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.

OCAS-TKBS-0002 Rev. 0 Intakes

Table 2. Inhalation Rate for Operations Cited in OCAS-TKBS-0002 Revision 0 

Worker Category Intake Rate for Type M Material Distribution

Administrative 25 pCi/day total U Constant value 

Administrative 0.35 pCi/day Th-2282 Constant value 

Administrative 0.35 pCi/day Th-2322 Constant value 

Production workers 82 pCi/day M total U Constant value 

Production workers 1.1 pCi/day Th-2282 Constant value 

Production workers 1.1 pCi/day M Th-2322 Constant value 

 1. Intake rates are normalized to units of calendar days. The intake period for operations is March 1, 

1951, through March 31, 1962. 

 2. Thorium intake rates are derived from ratios in ORAUT-OTIB-0043. Solubility types for thorium are 

based on recommendation in ICRP Report 68. 

Table 3. Ingestion Rate for Operations Cited in OCAS-TKBS-0002 Revision 0 

Worker Category Intake Rate Type M Material Distribution

Administrative 83 pCi/day total U Constant value 

Administrative 1.2 pCi/day Th-2282 Constant value 

Administrative 1.2 pCi/day Th-2322 Constant value 

Production workers 270 pCi/day total U Constant value 

Production workers 3.6 pCi/day Th-2282 Constant value 

Production workers 3.6 pCi/day Th-2322 Constant value 

1. Intake rates are normalized to units of calendar days. The intake period for operations in March 1, 

1951, through March 31, 1962. 

2. Thorium intake rates are derived from ratios in ORAUT-OTIB-0043. 

3. Ingestion intakes provide bounding dose to the stomach intestine, upper large intestine, lower large 

intestine, and colon. The f1 values are 0.02 for uranium ingestions and 0.0005 for thorium ingestions.

Revised Intakes Cited in Rev. 02 of OCAS-TKBS-0002

Table 4. Inhalation Rate for Building 551,2,3

Radionuclides Intake (pCi/d)

Production Workers

Intake (pCi/d) 

Administrative Workers

U-238, Th-230, U-234, Pb-210, Po-210 41 13 

Th-231, Pa-231, Ac-2274

1.9 0.59 

Ra-226 1.9 0.59 

Th-232, Ra-228, Th-228 1.4 0.41 

 1. Intake rates have been normalized to calendar days. 

 2. Intakes are based on Type M lung solubility for materials likely to have been present in Building 55 

operations except for thorium, lead, and polonium. Pb-210 is Type F, and Po-210 is Types F or M per 

ICRP 1994. Thorium could have been Type M or Type S. Thorium and polonium solubility types must be 

selected based on the types that provide the largest dose to the organ or tissue of concern. 

 3. See Table 3b of OCAS-TKBS-0002, Rev. 02, for dose to tissues of the gastrointestinal tract. 

 4. U-235 is allowed for in the U-238 and U-234 values. Values given are for radionuclides in the U-235 chain. 
Effective Date: 

March 23, 2009 

Revision No. 

0

Document No. 

SCA-TR-TASK3-0012

Page No. 

13 of 25

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.

Table 5. Ingestion Rate for Building 551,2 

Radionuclide f1 Values4 Intake (pCi/d)

Production Workers

Intake (pCi/d) 

Administrative Workers

U-238, U-234, 

Th-230 

Pb-210 

Po-210 

0.02 

0.0005 

0.2 

0.1 

139 41 

Th-231, Pa-231, Ac-2273 0.0005 6.4 1.9 

Ra-226 0.2 6.4 1.9 

Th-232, Th-228 

Ra-228 

0.0004 

0.2 4.5 1.4 

1. Intake rates are normalized to units of calendar days. 

2. Ingestion intakes provide bounding dose to the stomach, small intestine, upper large intestine, lower large 

intestine, and colon. See Table 3a [of OCAS-TKBS-0002, Rev. 02] for estimating dose to all other tissues. 

3. U-235 is allowed for in the U-238 and U-234 values. Values given are for radionuclides in the U-235 chain. 

4. fl values are from ICRP 68. 

3.4 REVISION TO RADON EXPOSURE ESTIMATES 

In the absence of Blockson-specific radon measurements, NIOSH employed surrogate values 

described in ORAUT-OTIB-0043, Revision 00, Characterization of Occupational Exposure to 

Radium and Radon Progeny During Recovery of Uranium from Phosphate Material. 

Initial radon dose estimates defined in Revision 0 of OCAS-TKBS-0002 were based on a 

geometric mean radon air concentration value of 0.751 pCi/l having a geometric standard 

deviation (GSD) of 2.0 and an assumed equilibrium fraction of 0.4. These values translated into 

annual exposures as reproduced in Table 6. 

Table 6. Radon Exposures Cited in OCAS-TKBS-0002 Revision 00 

Dose Component Annual Dose/Exposure1 Distribution

Radon progeny 0.036 WLM (lungs only) Lognormal, GSD=2.0 

Radon progeny 75 rem alpha (ET1 only)2 Lognormal, GSD=2.0 

Radon progeny 0.30 rem alpha (ET2 only)2 Lognormal, GSD=2.0 

Radon gas 0.002 rem alpha (non-respiratory tract tissues only) Constant value 

1. Exposure and dose values from ORAUT-OTIB-0043. 

2. ET1 and ET2 dose conversion factors from OCAS-TIB-0011. 

In Revision 01 of OCAS-TKBS-0002 radon dose estimates were based on the identical dataset 

described in ORAUT-OTIB-0043. However, the geometric mean of 0.751 pCi/l and GSD of 2.0 

were replaced with the constant 95th percentile radon air concentration of 2.33 pCi/l and 

corresponding annual doses reproduced in Table 7. 
Effective Date: 

March 23, 2009 

Revision No. 

0

Document No. 

SCA-TR-TASK3-0012

Page No. 

14 of 25

 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:

Table 7. Radon Exposures Cited in OCAS-TKBS-0002 Revision 01 

Dose Component Annual Dose/Exposure1 Distribution

Radon progeny 0.112 WLM (lungs only) Constant value 

Radon progeny ET1 and ET2 tissues2

Constant value 

Radon gas 0.002 rem alpha (non-respiratory tract tissues only) Constant value 

1. Exposure and dose values from ORAUT-OTIB-0043. Values are normalized for a 365 day year. 

2. ET1 and ET2 doses are to be applied as alpha dose and calculated from WLW values using 

conversion factors in OCAS-TIB-0011. 

3.5 CHANGES ASSOCIATED WITH EXTERNAL EXPOSURE 

Penetrating Radiation. Revisions to external penetrating exposures reflect the addition of 

numerous radionuclides contained in yellowcake inclusive of Th-232 and its progeny. As a 

result of the expanded list of contributing radionuclides, dose rates at 30 cm from a drum of 

yellowcake increased by a factor of about 6.6. 

To determine annual doses, the median external dose was based on an exposure period of 

400 hours per year at a 1-foot distance from a drum with a GSD of 2.7; for a 95th percentile 

value, the exposure duration was assumed at 2,000 hours per year. 

Beta Dose. The expanded list of radionuclides that were assumed to exist in yellowcake also 

increased estimates of beta doses to the skin. The original median beta dose to skin of 0.8 rem 

per year with a GSD of 2.7 increased to 1.2 rem per year with a GSD of 2.7. Furthermore, 

Revision 01 of OCAS-TKBS-0002 also added a beta skin dose of 1.5 rem per year from 

contaminated clothing, and an annual dose of 30 rem to hands and forearms from contact with 

yellowcake. 

3.6 REVISIONS TO DOSES FROM RESIDUAL CONTAMINATION 

A modest change to external exposures from residual facility contamination resulted from shift 

in fractional contribution of photon energy. In Revision 00 of OCAS-TKBS-0002, the photon 

dose was divided equally between 30–250 keV and the >250 keV energy ranges; in Revision 01, 

the photon dose is split 10% for 30–250 keV and 90% for >250 keV. 

Internal Dose. The revised increase in the number of radionuclides assumed present in 

yellowcake during the years of uranium extraction (see Section 3.5 above) also raised estimates 

of inhalation and ingestion intake rates post-1962 from residual contamination. 

The assigned solubility classes of inhaled or ingested radionuclides from residual 

contamination were identical to those assigned during the uranium extraction period. Except 

for Th, Pb, and Po, all other intakes are assumed Type M. 

Radon Exposures. Revision 0 of OCAS-TKBS-0002 did not address potential exposure to radon 

in Building 55 after the cessation of uranium extraction in 1962. In Revision 01, radon exposure 

from declining residual contamination is assumed to have occurred. Starting with the pre-1962 

operational annual exposure of 0.112 WLM, NIOSH assumed a decline in radon that paralleled 

the decline in residual surface contamination. 
Effective Date: 

March 23, 2009 

Revision No. 

0

Document No. 

SCA-TR-TASK3-0012

Page No. 

15 of 25

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.

4.0 SUBTASK 3: ASSESS NIOSH’S SPECIFIC METHODS FOR 

CORRECTIVE ACTION 

In instances where the PER involves a technical issue, SC&A will review the scientific basis 

and/or sources of information to ensure the credibility of the corrective action and its consistency 

with current/consensus science. 

4.1 GENERAL COMMENTS 

SC&A examined all relevant changes introduced in OCAS-TKBS-0002, Revision 01 (and 

Revision 02) that gave rise to OCAS-PER-020 and concludes the following: 

(1) All changes introduced in revisions to OCAS-TKBS-0002 had the effect of either adding 

radiation exposure that had not been previously considered in Rev. 0 of OCAS-TKBS0002 or, by varying degree, increased previous internal and external dose estimates. 

(2) With potentially three exceptions, all revisions were either based on credible science or 

employed reasonable, plausible assumptions that were claimant favorable. 

Of potential concern regarding the adequacy of OCAS-PER-020, therefore, are three issues with 

significant potential impacts on worker dose reconstruction. Important to note here is the fact 

that these issues have already been raised by SC&A at previous Blockson Work Group 

meetings/discussions. A brief overview of the issues is presented below, with the intent to 

stimulate further discussion and resolution. 

4.2 ISSUE #1: NIOSH’S ASSIGNED SOLUBILITY CLASS TYPE M FOR 

URANIUM AND ITS USE FOR CONVERTING URINE EXCRETION DATA TO 

INHALATION QUANTITIES FOR BUILDING 55 MAY BE INAPPROPRIATE 

In Section 3.2.2 of OCAS-TKBS-0002, Revision 01, NIOSH states the following: 

. . . Various studies have shown that U3O8 closely corresponds to the clearance 

rate associated with material Type M. Some studies have also shown that high 

fired material can produce uranium compounds that clear more slowly from the 

lungs, i.e., indicative of material Type S (Rucker, et al. 2001). Type M uranium is 

the most appropriate lung solubility material type based on the process used for 

uranium extraction at Blockson. The U3O8 product was produced from wet 

phosphoric acid by filtering the precipitated uranium and then using a dryer to 

dewater the solids (Blockson 1953a). . . . Based on these processes and the 

results of various studies that have been summarized by Rucker, et al., Type M 

material is used to derive intakes from bioassay results. 

. . . Individual worker intakes were determined using IMBA-ExpertTM by assuming 

a chronic inhalation intake of Type M uranium with parameters recommended by 

the ICRP [ICRP 1994]. [Emphasis added.] 
Effective Date: 

March 23, 2009 

Revision No. 

0

Document No. 

SCA-TR-TASK3-0012

Page No. 

16 of 25

 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:

OCAS-TKBS-0002 provides the following information regarding the Blockson urine bioassay 

data and their interpretation: 

(1) One hundred twenty-two (122) urine sample results are available, for which total 

uranium levels were defined fluorometrically. 

(2) Urine sample data represent a total of 20 Blockson workers. 

(3) Results ranged from 0 to 17 μg uranium per liter urine. 

(4) Bioassay data reported for uranium in μg/l were converted to daily excretion defined in 

pCi/day by multiplying values by 1.4 liter/day and 0.677 pCi/μg of uranium. 

(5) Individual worker intakes were determined using IMBA ExpertTM by assuming a chronic 

inhalation intake of Type M uranium. 

(6) For daily intake rate calculation purposes, intakes were assumed to have occurred 

beginning in the year sampled and ending with the last sample date. 

Regarding NIOSH’s basis for assigning solubility class Type M for uranium, SC&A reviewed 

the cited reference (Rucker et al. 2001) and came to a different conclusion. Rucker et al. (2001) 

did, in fact, cite a 2000 DOE Standard (Guide of Good Practices for Occupational Radiological 

Protection in Uranium Facilities), which had classified U3O8 as Class W. However, the 2000 

DOE Standard was replaced by a 2004 DOE Standard with the same title (DOE 2004). In 

Table 2-11 of DOE 2004, U3O8 is classified of “Y.” Under the new ICRP classification system, 

solubility class “Y” is now designated as absorption Type S. It must further be noted that ICRP 

Publication 68 (ICRP 1994) recommends solubility class Type S for UO2 and U3O8, as shown in 

Exhibit #2. 

On the basis of these recommendations and the absence of empirical site-specific solubility 

studies, there is no technical justification for NIOSH to unequivocally assign a solubility class M 

for Blockson. It is SC&A’s opinion that for dose reconstruction, either Type M or Type S 

should be assumed, depending on which type results in a more claimant-favorable dose 

assessment. Lastly, support for Type S solubility class is provided in a 1984 study that was 

acknowledged by NIOSH but dismissed, as explained below. 
Effective Date: 

March 23, 2009 

Revision No. 

0

Document No. 

SCA-TR-TASK3-0012

Page No. 

17 of 25

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.

EXHIBIT #2: ICRP’s Default f1 Value: U – Zr 

Table A.38-7. ICRP-recommended “default” values of f1 (U - Zr).

Element Route of Intake - 

Type of Material

Default 

Value of f1

ICRP 

Publ. #(a)

Comments

U - Uranium Inhalation - F 0.02 71 - 

 - M 0.02 71 Recommended default in the absence 

of specific information. 

 - S 0.002 71 - 

 - F 0.02 68 Most hexavalent compounds [UF6, 

UO2F2 and UO2(NO3)2].

 - M 0.02 68 Less soluble compounds (UO3, UF4, 

UCl4) and most other hexavalent 

compounds. 

 - S 0.002 68 Highly insoluble compounds (UO2 and 

U3O8). 

 Ingestion 0.02 68 Unspecified compounds. 

 Ingestion 0.002 68 Most tetravalent compounds (UO2, 

U3O8, UF4). 

Y – Yttrium Inhalation - M 0.0001 30(2), 68 Unspecified compounds. 

 - S 0.0001 30(2), 68 Oxides and hydroxides. 

 Ingestion 0.0001 68 All compounds. 

Zn – Zinc Inhalation - F 0.5 71 - 

 - M 0.1 71 Recommended default in the absence 

of specific information. 

 - S 0.01 71 - 

 - S 0.5 68 All compounds. 

 Ingestion 0.5 68 All compounds. 

Zr - Zirconium Inhalation - F 0.002 71 - 

 - M 0.002 71 Recommended default in the absence 

of specific information. 

 - S 0.002 71 - 

 - F 0.002 68 Unspecified compounds. 

 - M 0.002 68 Oxides, hydroxides, halides and 

nitrates. 

 - S 0.002 68 Zirconium carbide. 

 Ingestion 0.002 68 All compounds. 

(a)Key to ICRP Publications:

Publ. #30(2) - ICRP Publication 30: Part 2. (ICRP 1980).

Publ. #68 – ICRP Publication 68 (ICRP 1994).

Publ. #71 – ICRP Publication 71 (ICRP 1995). 
Effective Date: 

March 23, 2009 

Revision No. 

0

Document No. 

SCA-TR-TASK3-0012

Page No. 

18 of 25

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.

Summary of the 1984 Eidson and Damon Study. As part of a potential alternative method for 

estimating inhalation intakes at Building 55, NIOSH had reviewed air sampling data reported in 

a 1984 study by Eidson and Damon. This study cited uranium air concentrations in behalf of 

yellowcake packaging operations at four uranium processing mills, which employed the 

following six steps common to those at Blockson: 

(1) No Activity* – This includes time when no other activity is occurring or has occurred for 

at least two hours prior. Generally, the mill was shut down for maintenance or all 

available dried yellowcake was packaged during a previous shift. Workers are generally 

not present in the packaging area during this time. 

(2) Barrel loading – This occurs when a barrel is placed under a hopper containing the dried 

yellowcake. The yellowcake is allowed to fall into the barrel. The amount of time 

workers spend in this area depends on the volume of the yellowcake in the hopper. 

(3) Barrel uncovering – This step occurs when a filled barrel is removed from beneath the 

hopper. In some cases, the barrel may be vibrated to compact the yellow cake before 

removing the barrel from beneath the hopper. (It is not known if the barrels at Blockson 

were vibrated.) 

(4) Powder sampling – This occurs when a worker takes a sample of yellowcake for 

laboratory analysis. At Blockson, this was done prior to the pans of yellowcake being 

dumped into the barrels. 

(5) Lid sealing – This occurs when a worker places a lid on the barrel and seals it. 

(6) Other activities – This step includes maintenance and cleaning of the area with water 

hoses. 

Airborne concentrations reported by Eidson and Damon (1984) in behalf of the six packaging 

steps are summarized in Table 8 as median, maximum, and minimum values. On the basis of 

these empirical measurements, the authors concluded that the median aerosol concentrations in 

the packaging areas ranged from 27 pCi/m3

 to 230 pCi/m3 uranium. 

Table 8. Airborne Uranium Concentrations During Packaging Operations of Yellowcake 

(Source: Data from Table 1 of Eidson and Damon 1984) 

Uranium Concentration (pCi/m3) Packaging Step Medium Maximum Minimum 

No Activity 27 34 18 

Drum Loading 115 948 14 

Powder Sampling 55 68 12 

Lid Sealing 230 433 74 

Small Spill 1,963 2,031 1,286 

 

*

 Note: The definition of “No activity” given above was taken verbatim from Eidson and Damon (1984). 
Effective Date: 

March 23, 2009 

Revision No. 

0

Document No. 

SCA-TR-TASK3-0012

Page No. 

19 of 25

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.

Using the lowest median air concentrations of 27 pCi/m3

 defined for the “No activity” 

measurement, a daily inhalation intake of 259 pCi/day U is estimated (i.e., 27 pCi/m3 × 1.2 m3/hr 

× 8 hr/d = 259 pCi/d). This minimum value is more than three times the 95th percentile value of 

82 pCi/d derived by NIOSH from urine data that assumes the solubility class Type M. 

NIOSH dismissed this discrepancy with the following explanation (see Section 3.2.2 of OCASTKBS-0002, Rev. 01): 

Comparison of the above uranium mill results [i.e., study data reported by Eidson 

and Damon 1984] to Blockson operations cannot readily be made due to 

differences in operations and in quantities produced. . . . The mills processed 

uranium bearing ores that contained larger relative uranium concentrations, and 

in typically larger quantities.

SC&A questions the merit of this explanation for the following reasons: (1) the specific activity 

level of yellowcake must be assumed as constant regardless of the starting levels of uranium in 

the ore from which it was derived; (2) minimum and median values reported by Eidson and 

Damon (1984) must reasonably be assumed to have involved packaging activities involving a 

single drum at-a-time; and (3) whenever site-specific data are unavailable, NIOSH routinely 

makes use of surrogate data such as these. 

In order to illustrate the potential impact on converting urine data to inhalation intake by 

erroneously assuming a solubility class Type M for uranium (if, in fact, the true solubility had 

been Type S), the following IMBA calculations were performed for a 24-hour termination urine 

sample containing 10 μg of total uranium after a 1-year and a 5-year chronic exposure period. 

Derived Inhalation (pCi/day) 

Exposure Duration Type S Type M Ratio Type S/Type M

1 year 664 109 6.1 

5 year 546 84 6.5 

Our sample calculation suggests that, if the solubility class Type S had been applied by NIOSH 

to convert Blockson urine data, a daily inhalation quantity of about 600 pCi would have been 

estimated. Such a value would be entirely consistent with the empirical air monitoring data 

reported by Eidson and Damon (1984), as summarized in Table 8. 

4.3 ISSUE #2: NIOSH’S ASSIGNED f1 VALUE OF 0.02 FOR URANIUM AND ITS 

USE FOR CONVERTING URINE EXCRETION DATA TO 

INHALATION/INGESTION QUANTITIES MAY BE INAPPROPRIATE 

Section 3.2.2 of OCAS-TKBS-0002, Revision 01, allows for an alternative use/interpretation of 

Blockson urine bioassay data, as given in the following statements: 

Workers also had the potential to ingest uranium from contact with contaminated 

surfaces or from eating or drinking in the area [i.e., Building 55]. When deriving 

intakes from the bioassay results, a chronic ingestion of uranium results in a 
Effective Date: 

March 23, 2009 

Revision No. 

0

Document No. 

SCA-TR-TASK3-0012

Page No. 

20 of 25

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.

higher dose to certain tissues of the gastrointestinal tract when compared to the 

dose from the inhalation intakes described above. Therefore, intakes are 

presented in Table 4b based on the presumption that all the uranium in the 

workers urine was due to ingestion. . . . Since bioassay results are from intakes 

by all pathways a worker should be assigned Building 55 intakes from inhalation 

or ingestion, not both. [Emphasis added.] 

Inspection of Table 4b in OCAS-TKBS-0002, Revisoin 01, identifies the assumed f1 value of 

0.02 for uranium. As noted in Exhibit #2 above, ICRP Publication 68 recommends a 10-fold 

lower default f1 value of 0.002 for most tetravalent uranium compounds that include UO2, U3O8, 

and UF4. 

Use of the lower ICRP f1 value for converting bioassay data to ingestion quantities would have 

the obvious effect of raising ingestion quantities, which in turn would differentially raise doses to 

select tissues during transit through the GI tract. 

4.4 ISSUE #3: THE ASSIGNED RADON EXPOSURE VALUE OF 0.112 WLM/YEAR 

AS A BOUNDING VALUE FOR BLOCKSON MAY BE INAPPROPRIATE 

Currently, NIOSH’s bounding radon estimate of 0.112 WLM per year for Blockson workers was 

based on 1998 data reported by the Florida Institute of Phosphate Research (FIPR 1998), as 

summarized in ORAUT-OTIB-0043. Data extracted from this study and deemed applicable to 

Blockson by NIOSH yielded a radon air concentration of 2.33 pCi/l at the 95th percentile. 

Applying the fractional progeny equilibrium value of 0.4, the annual bounding exposure of 

0.112 WLM was derived by means of the following equation: 

Radon Exposure pCi l      WL

pCi l  work mo yr 



 

 2 33   0 01

. / 0 4 12 .

/ . /

 = 0.112 WLM/yr 

SC&A has previously questioned the value of 0.112 WLM per year as a bounding value, as well 

as the applicability of FIPR (1998) data as the basis for this value. Using first principles, SC&A 

developed a model for Blockson radon exposures that was described in the report, “Evaluation of 

Radon Levels in Building 40 at Blockson Chemical” that was submitted for evaluation to NIOSH 

and the Blockson Work Group on July 29, 2008, and posted on the OCAS website on August 12, 

2008. 

SC&A’s model yielded exposures that were substantially higher (i.e., 62 pCi/l ) than NIOSH’s 

bounding value of 2.33 pCi/l of radon air concentration and the corresponding 0.112 WLM/yr 

exposure. During the October 15, 2008, Blockson Work Group meeting, SC&A was asked to 

address issues raised by NIOSH and its consultant, Dr. Naomi Harley, and to reassess select 

parameters used in our model. Key model parameters of concern included the range of radon 

evolution fractions and building ventilation rates. 

In response to the Work Group’s directive, SC&A issued a supplemental report on December 8, 

2008, entitled “Revised Calculation of Rn222 Concentrations in Building 40.” SC&A’s revised 
Effective Date: 

March 23, 2009 

Revision No. 

0

Document No. 

SCA-TR-TASK3-0012

Page No. 

21 of 25

 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.

calculation yielded radon air concentrations in Building 40 of 5.97 pCi/l and 36.30 pCi/l at the 

50th and 95th percentile levels, respectively. 

However, NIOSH opined that a more realistic range of radon evolution fractions from the 

digestion of ore in hot sulfuric acid and a lower building air exchange rate would yield radon 

levels of 3.65 pCi/l and 12.92 pCi/l at the 50th and 95th percentile values. Figure 1 depicts the 

two datasets and their differences, which at the time of this review, however, have not been 

formally resolved. 

Figure 1. Comparison of 222Rn Concentrations Using SC&A and NIOSH Parameters 

NOTICE:
Effective Date: 

March 23, 2009 

Revision No. 

0

Document No. 

SCA-TR-TASK3-0012

Page No. 

22 of 25

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.

5.0 SUBTASK 4: EVALUATE THE PER’S STATED APPROACH FOR 

IDENTIFYING THE UNIVERSE OF POTENTIALLY AFFECTED 

DOSE RECONSTRUCTIONS; AND ASSESS THE CRITERIA BY 

WHICH A SUBSET OF POTENTIALLY AFFECTED DOSE 

RECONSTRUCTIONS WAS SELECTED FOR RE-EVALUATION 

In Section 3.0 of OCAS-PER-020 entitled, “Plan for Resolution or Corrective Action,” NIOSH 

provides the following explanation and plan for corrective action: 

It is not possible to determine the magnitude of the change to dose without a new 

dose estimate. Since (as of issuance of this PER) no Blockson Chemical Company 

claims have yet been completed with the newest revision to the TBD, NIOSH is 

requesting that all Blockson Chemical Company claims with a Probability of 

Casusation less than 50% be returned for a new estimate. . . . A new dose 

reconstruction will be completed for each of the claims using the latest revision to 

the Blockson TBD. [Emphasis added.] 

NIOSH identified a total of 91 claims for which a dose reconstruction was performed prior to the 

revision of OCAS-TKBS-0002 and for which the calculated POC was less than 50%. SC&A 

concurs that the selection criteria used by NIOSH do, in fact, encompass the universe of 

potentially affected dose reconstructions and, therefore, obviate the need for further analysis. 
Effective Date: 

March 23, 2009 

Revision No. 

0

Document No. 

SCA-TR-TASK3-0012

Page No. 

23 of 25

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.

6.0 SUBTASK 5: CONDUCT AUDITS OF DOSE RECONSTRUCTIONS 

AFFECTED BY OCAS-PER-020 

The selection and number of dose reconstructions to be audited by SC&A will be made by the 

Advisory Board. At this time, NIOSH has informed SC&A that all 91 claims that were 

identified as potentially affected by OCAS-PER-020 have been reassessed. Of the 91 claims 

reassessed, dose reconstructions that were based on new guidance contained in Revision 01 of 

OCAS-TKBS-0002 resulted in 32 claims for which the new POCs were 50% and were, 

therefore, compensable. For the remaining 59 claims, revised tissue doses increased 

significantly, but resulted in POC values that were, nevertheless, below 50%. 

Thus, the universe of dose reconstructions from which the Advisory Board may select a subset 

for audit under Subtask 5 is currently defined by these 59 Blockson claims. However, given the 

three unresolved issues raised under Subtask 3 in this review [i.e., (1) solubility class Type S for 

U, (2) f1 value of 0.002 for U, and (3) higher radon levels in Building 40], the Board may wish to 

delay a dose reconstruction audit under OCAS-PER-020 until these issues are resolved. 
Effective Date: 

March 23, 2009 

Revision No. 

0

Document No. 

SCA-TR-TASK3-0012

Page No. 

24 of 25

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.

7.0 REFERENCES 

Blockson 1953a. Uranium Recovery from Wet Process Phosphoric Acid, Abstract, prepared by 

Stoltz, Emil Jr., February 23, 1953 [SRDB Ref ID 4027]. 

DOE (U.S Department of Energy) 2000. DOE Standard: Guide of Good Practices for 

Occupational Radiological Protection in Uranium Facilities. DOE-STD-1136-2000: 2-16. 

DOE (U.S Department of Energy) 2004. DOE Standard: Guide of Good Practices for 

Occupational Radiological Protection in Uranium Facilities, DOE-STD-1136-2004. 

http://www.hss.energy.gov/nuclearsafety/techstds/standard/std1136/doe-std-1136-2004.pdf. 

Eidson, A.F., and E.G. Damon. 1984. “Predicted Deposition Rates of Uranium Yellowcake 

Aerosols Sampled in Uranium Mills,” Health Physics, 46(1): 165-176. 

FIPR (Florida Institute of Phosphate Research) 1998. Evaluation of Exposure to Technologically 

Enhanced Naturally Occurring Radioactive Materials (TENORM) in the Phosphate Industry, 

Publication 05-046-155. Bartow, Florida. 

ICRP (International Commission on Radiological Protection) 1980. Limits for Intakes of 

Radionuclides by Workers: Part 2. ICRP Publication 30; Ann ICRP 4(3/4). Oxford: Pergamon 

Press. 

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

Intakes of Radionuclides by Workers, ICRP Publication 68; Ann ICRP 24(4). Oxford: Elsevier 

Science Ltd. 

ICRP (International Commission on Radiological Protection) 1995. Age-dependent Doses to 

Members of the Public from Intakes of Radionuclides: Part 4 Inhalation dose Coefficients. ICRP 

Publication 71; Ann ICRP 25(3-4). Oxford: Elsevier Science Ltd. 

OCAS-PER-020. 2007. Blockson TBD Revision, Rev. 0, National Institute for Occupational 

Safety and Health, Office of Compensation Analysis and Support: Cincinnati, Ohio. July 31, 

2007. 

OCAS-PR-008. 2006. Preparation of Program Evaluation Reports and Program Evaluation 

Plans, Revision 2. National Institute for Occupational Safety and Health, Office of 

Compensation Analysis and Support: Cincinnati, Ohio. December 6, 2006. 

OCAS-TIB-0011. 2006. Lung Dose Conversion Factor for Thoron WLM, Rev. 2. National 

Institute for Occupational Safety and Health, Office of Compensation Analysis and Support: 

Cincinnati, Ohio. January 13, 2006. 

OCAS-TKBS-0002 (Rev. 0). 2006. Technical Basis Document for Atomic Energy Operations 

at Blockson Chemical Company, Joliet, Illinois, Rev. 0. National Institute for Occupational 

Safety and Health, Office of Compensation Analysis and Support: Cincinnati, Ohio. September 

11, 2006. 
Effective Date: 

March 23, 2009 

Revision No. 

0

Document No. 

SCA-TR-TASK3-0012

Page No. 

25 of 25

 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:

OCAS-TKBS-0002 (Rev. 01). 2007. Technical Basis Document for Atomic Energy Operations 

at Blockson Chemical Company, Joliet, Illinois, Rev. 01. National Institute for Occupational 

Safety and Health, Office of Compensation Analysis and Support: Cincinnati, Ohio. June 20, 

2007. 

OCAS-TKBS-0002 (Rev. 02). 2007. Technical Basis Document for Atomic Energy Operations 

at Blockson Chemical Company, Joliet, Illinois, Rev. 02. National Institute for Occupational 

Safety and Health, Office of Compensation Analysis and Support: Cincinnati, Ohio. November 

21, 2007. 

ORAUT-OTIB-0043. 2006. Characterization of Occupational Exposures to Radium and Radon 

Progeny during Recovery of Uranium from Phosphate Materials, Rev. 00. Oak Ridge 

Associated Universities: Cincinnati, Ohio. January 6, 2006. 

Rucker, T.L. et al. 2001. Uranium Lung Solubility Class Selection at Bechtel Jacobs Company 

LLC-Operated Facilities. http://www.lanl.gov/BAER-Conference/BAERCon-47p-Rucker.pdf. 

SC&A. 2008. Evaluation of Radon Levels in Building 40 at Blockson Chemical, Revised Draft, 

SC&A, Inc., Vienna, VA. August 12, 2008. 

http://www.cdc.gov/niosh/ocas/pdfs/abrwh/scarpts/scablockrad.pdf 

SC&A. 2007. Revised Calculation of Rn222 Concentrations in Building 40, Draft Letter Report, 

SC&A, Inc., Vienna, VA. January 10, 2007. 

http://www.cdc.gov/niosh/ocas/pdfs/abrwh/scarpts/drblockseceval.pdf