Fernald SEC Petition and 

Site Profile Review Status 

Update

Presented by John Stiver (SC&A, Inc.)

Meeting of the Advisory Board on Radiation and Worker Health 

Held in Santa Fe, New Mexico

August 23–24, 2017
Background – Fernald [Feed Materials Production 

Center (FMPC)] Operations and Processes

 The FMPC was located near the unincorporated village of Fernald in the Great Miami 

River Valley, about 20 miles northwest of Cincinnati in southwestern Ohio. The FMPC 

site covered an area of 1,050 acres. The production area encompassed approximately 

136 acres in the center of the site. 

 Fernald began operations in 1951 and was fully operational by the end of 1954; 

production ceased in 1989. Its primary function was to convert uranium ore 

concentrates and recycled materials to either uranium oxides or highly purified 

uranium ingots and billets for machining or extrusion into tubular forms of 

assorted uranium enrichment. These products were prepared for use as production 

reactor fuel cores and target fuel elements. In addition, thorium was processed, but in 

small proportion to uranium.

 Production area facilities included nine separate plants, the pilot plant, ancillary 

buildings, and administrative buildings that were connected with a network of 

roadways. These facilities, along with concrete storage pads, gravel ground cover, 

railroad access, sanitary landfill, and metal scrap piles, were surrounded by security 

fencing.

 Outside the fenced production area, the Waste Storage Area included six low-level 

radioactive waste storage pits, two earthen-bermed concrete silos containing K-65 

residues (high specific activity radium-bearing residues), one concrete silo containing 

metal oxides, and all affected adjoining areas. 2
Historical Overview – November 2006–Present

 Site Profile Review – 11/10/2006

 Identified 33 findings 

 SEC Petition 00046: Proposed class qualified for evaluation (April 2006) – All 

employees of DOE, DOE contractors, and subcontractors employed at FMPC from 

January 1, 1951, through December 31, 1989

 SEC ER Review – 07/02/2007

 Six principal SEC issues were identified

 Issue 1: Coworker model for uranium internal exposures

 Issue 2: Validation of the HIS-20 database

 Issue 3: Recycled uranium (RU)

 Issue 4: Use of radon breath data for reconstructing doses from inhalation of Ra-226 and 

Th-230

 Issue 5: Review of radon emissions from the K-65 silos and associated exposures

 Issue 6: Reconstruction of internal exposures from inhalation of Th-232 [daily weighted 

exposures (DWEs) (Issue 6A) and chest counts (Issue 6B)]

 SEC 4.5-1: Absence of performance standards/quality assurance for personnel 

dosimeters

 See Fernald issues matrix, Rev. 5, for detailed narrative on finding 

resolution

3
Historical Overview (cont.)

 Twenty-two Work Group Meetings (August 2007–July 2017)

 Many white paper exchanges and Work Group discussions

 After July 28, 2017, Work Group meeting:

 Three classes have been added to the SEC

 June 2012: All employees of DOE, DOE contractors, or subcontractors who worked at all 

locations at the FMPC in Fernald, Ohio, from January 1, 1968, through December 31, 

1978; based on inability to reconstruct internal doses to thorium from chest count 

data reported in milligrams thorium 

(https://www.cdc.gov/niosh/ocas/pdfs/sec/fernald/fmpchhsdes-46.pdf)

 September 2013: All employees of the FMPC in Fernald, Ohio, who were not employed 

by National Lead of Ohio, NLO, or the Department of Energy or its predecessor agencies, 

who worked at the FMPC from January 1, 1951, through December 31, 1983; based 

on insufficient internal monitoring data for other-than-prime contractor and DOE 

employees during that time 

(https://www.cdc.gov/niosh/ocas/pdfs/sec/fernald/fmpchhsdes-46b.pdf)

 September 2013: All employees of DOE, DOE contractors, or subcontractors who 

worked at all locations at the FMPC in Fernald, Ohio, from January 1, 1954, through 

December 31, 1967; based on inability to reconstruct internal doses to thorium 

from time-weighted airborne radioactivity concentration values termed daily 

weighted exposure (DWE) 

(https://www.cdc.gov/niosh/ocas/pdfs/sec/fernald/fmpchhsdes-46c.pdf)

4
SEC Issue 1: Coworker Model for Uranium 

Internal Exposures

 Description of Issue:

 Completeness and adequacy of uranium bioassay data for dose 

reconstruction and to support ORAUT-OTIB-0078, Fernald 

internal dosimetry coworker model

 Issue Resolution:

 OTIB-0078 was revised 3 times from 2009 to 2016; the coworker 

model was incorporated into the occupational internal dose 

technical basis document (TBD-5), Rev. 03 (May 2016), and the 

TIB was then cancelled.

 Issues related to the applicability of the uranium coworker model 

to Fernald construction workers were the basis for the addition of 

a class of workers to the SEC (non-NLO/NLO, Inc. employees 

from 1951 to 1983).

5
SEC Issue 2: Validation of the HIS-20 Database 

(Issue 2 has two parts – 2A and 2B)

 Description of Issue 2A:

 Complete the validation of the accuracy with which hardcopy 

dosimetry data were converted into electronic data for the 

HIS-20 database.

 CanberraTM HIS-20 database used in uranium bioassay (coworker) study

 Status of Issue:

 On December 3, 2010, NIOSH delivered a complete validation 

study that resolved all of SC&A’s concerns.

 At the February 8, 2011, Work Group meeting, it was 

recommended that Subpart A of Issue 2 be closed.

6
SEC Issue 2: Validation of the HIS-20 Database 

(continued)

 Description of Issue 2B:

 Concerns about the integrity of the hardcopy bioassay data, as 

raised by the petitioner

 Status of Issue:

 Although SC&A prepared a report that describes strategies for 

investigating data integrity issues that could adversely affect the 

ability to reconstruct internal doses, the WG agreed that any 

such investigations would require considerable time and costs 

and will likely be inconclusive – not tasked; issue closed

7
Issue 3: Recycled Uranium

 Description of Issue 3:

 Concern: Default concentrations (on U mass basis) of Pu-239 (100 ppb 

U), Np-237 (3,500 ppb U), and Tc-99 (9,000 ppb U) associated with RU 

at Fernald may not be bounding for some classes of worker activities, 

buildings, and time periods.

 Dosimetric significance: Pu dose 2–5 times U dose (bone surfaces, 

liver, red marrow)

 Three periods of interest (1953–1985a)

o 1953–1960: 45 MT storage; little exposure potential

o 1961–1972: RU processed but data suggest most was “within 

specification” (nominally 10 ppb U)

o 1973–1985: RU with high concentrations received from GDPs (termed 

POOS for “plutonium out of specification”)

o Post-1986: In 1986, WMCO replaced NLO as Fernald M&O and 

instituted comprehensive improvements in HP/IH programs

a Although SC&A’s SEC concerns about RU end in 1985, exposure potential to RU for Fernald workers 

continued throughout the life of the facility.

8
Issue 3: Recycled Uranium (cont.)

 Six WG meetings from October 2008 to July 2017

 Many white paper exchanges and discussions (2008–2012)

 February 2012: NIOSH and WG agreed to the following RU 

contaminant concentrations and moved the RU issue to site 

profile status

9

RU contaminant 1961–1972 1973–present

Pu-239 100 ppb U 400 ppb U

Np-237 3,500 ppb U 11,000 ppb U

Tc-99 9,000 ppb U 20,000 ppb U
Issue 3: Recycled Uranium (cont.)

 Status of Issue as of August 2017 

 TBD-5, Rev. 03 (March 2017): NIOSH proposes lower constituent 

concentrations than agreed upon by the WG for 1961–1972.

 Pu-239 (100 ppb U  10 ppb U), Np-237 (3,500 ppb U  400 

ppb U), Tc-99 (9,000 ppb  6,000 ppb U)

 NIOSH stated that the data do not support the original 

concentrations (factor of 10 was applied “administratively” to 

assure claimant favorability) and that “dose reconstructions are 

now done differently” than they were in 2012.

 SC&A remains concerned that these new defaults may not 

adequately bound intakes to workers not covered by the SEC 

(< 250 days).

 MgF2 process loop and impact on metal workers in Plant 5 and millwrights in 

Plant 1 (highest continuous exposure potential)

 NIOSH agreed to provide a more detailed explanation for their 

new default levels for 1961–1972.

 Issue remains active (TBD Findings 9 and 11 and SEC P3).

 Component related to Am-241 closed at July 28, 2017, WG 

meeting (Finding 10). 

10
SEC Issue 4: Use of Radon Breath Data for 

Reconstructing Doses from the Inhalation of Ra-226 

and Th-230

 Description of Issue 4: SC&A agrees – radon breath analysis is a 

scientifically valid method for reconstructing the intake of Ra-226 and 

Th-230 when the intake ratios of the two radionuclides are known and the 

impacted worker population can be identified.

 Remaining Issue – Reconstructing Th-230 dose in uranium- and radium-poor 

raffinates

 WG agreed that potential intakes could be bounded and moved this issue to site profile 

status.

 Status of Issue as of August 2017:

 Many white papers have been exchanged and discussed in previous WG 

meetings.

 July 28, 2017, WG meeting: NIOSH believes that there is no exposure potential 

to uranium- and radium-poor raffinates due to the nature of process equipment 

and physical form of the material. NIOSH to provide official written position on 

uranium- and radium-poor raffinates exposure potential.

 Issue remains active (TBD issues 7 and 8).

11
SEC Issue 5: Review of Radon Emissions from 

the K-65 Silos and Associated Exposures

 Description of Issue 5: SC&A Position

 Radon release rate from the K-65 silos as estimated by NIOSH is substantially 

underestimated.

 Method to derive the atmospheric dispersion factors, given the source term, is 

scientifically flawed but results in an overestimate of the atmospheric dispersion 

factors at receptor locations (still doesn’t compensate for underestimated source 

term).

 Status of the Issue:

 Many white papers have been exchanged; both sides “agree to disagree.”

 As a practical matter, NIOSH believed that this issue has little significance with 

respect to the dose reconstruction for actual claimants, and both parties (i.e., 

NIOSH and SC&A) agreed that this is not an SEC issue.

 April 2011: Board agreed to move from SEC issues to TBD issues.

 Status as of August 2017

 TBD-4, Rev. 01 (December 2015): NIOSH has incorporated the 95th percentile 

of the modeled doses in the RAC report, as agreed upon by the WG.

 Issue closed (TBD issues 25 and 26).

12
SEC Issue 6A: Reconstruction of Internal 

Exposures from the Inhalation of Th-232

(DWE Data) 

 Description of Issue 6A: Use of breathing zone (BZ) and GA 

sampling data and associated time-weighted air concentrations 

(DWEs) to reconstruct Th-232 intakes pre-1968

 Status of Issue:

 Many white papers exchanged and discussed over several WG meetings

 July 2013: SEC voted for all workers 1954–1967 based on inability to 

reconstruct intakes of Th-232 with sufficient accuracy from DWE data 

 Most DWE air sampling based on gross alpha activity was not focused on 

thorium work occurring at the site but rather on uranium work; thus, the 

samples contained unknown proportions of uranium and thorium.

 Workers could not reliably be placed in thorium-processing facilities during the 

periods of interest.

13
Issue 6B: Reconstruction of Internal Exposures 

from the Inhalation of Th-232 (Chest Count Data)

 Description of Issue 6B: Use of chest counts to reconstruct Th-232 

exposures (1968–1988)

 Two periods of interest

 1968–1978: Results reported in milligrams thorium

 April 2012: SEC voted for all workers from 1968 to 1978 based on 

inability to place a sufficiently accurate upper bound on intakes based 

on results reported in milligrams thorium

 empirical equation used to get mg thorium from count data 

 Not applicable to forms and varying equilibrium conditions at 

Fernald

 Extremely large uncertainties

 1979–1988: Reported in nCi thorium (based on Pb-212)

 WG accepted NIOSH methodology for reconstructing doses based on 

activity measurements of Pb-212

14
Finding 4.5-1: Absence of Performance 

Standards/Quality Assurance for Personnel Dosimeter

 Description of Finding 4.5-1:

 SC&A did not question the merits/use of the dosimetry data but implied 

the need to consider the quality of these data in context with stated 

limitations. SC&A recommended expanding the range of uncertainty that 

is normally afforded to personnel dosimeters that were used at the time 

to account for these deficiencies.

 More an issue of uncertainties introduced by human error:

 Control badges not routinely processed with badges worn by workers

 Did not have a bona fide official training program for the technicians who 

assessed the badges

 Finding Disposition:

 Because there was really no way to rectify the deficiencies, the WG 

agreed to close this out at the September 2014 WG meeting.

15
Fernald WG Recommendation on SEC-00046

The Fernald WG recommends that the Board 

find radiation doses can be estimated with 

sufficient accuracy for National Lead of Ohio 

(NLO) and NLO, Inc. and Westinghouse 

Materials Company of Ohio (WMCO) 

employees from 1979 through 1989, and for 

covered employees other than NLO and NLO, 

Inc. employees from 1984 through 1989. This 

would complete the Board’s consideration of 

SEC Petition 00046.

16
Site Profile Status Update

 Original Site Profile Review – 11/10/2006

 Of the 33 original findings, 27 are closed, 4 are in progress, and 2 were 

transferred to Subcommittee for Procedure Reviews (SCPR) 

 November 24, 2014, SC&A review of NIOSH white paper, Fernald 

Dose Reconstruction Methodology for the Post Special Exposure 

Cohort (SEC) Period, 1979–2006, Revision 2, June 23, 2014 

 7 findings and 7 observations

 May 12, 2016, SC&A review of Internal Dosimetry Coworker Data for 

the Feed Materials Production Center, ORAUT-OTIB-0078, Revision 

03, August 19, 2015

 2 findings and 6 observations

17
Findings In Progress or Transferred from 2006 Site 

Profile Review

 Findings 7 and 8 (raffinates poor in uranium and radium) In 

Progress

 July 28, 2017, WG meeting: NIOSH believes that there is no exposure potential 

to uranium- and radium-poor raffinates due to the nature of process equipment 

and physical form of the material. NIOSH to provide official written position on 

uranium- and radium-poor raffinates exposure potential. (Related to SEC Issue 

4; Slide 11)

 Findings 9 and 11 (RU) In Progress

 July 28, 2017, WG meeting: NIOSH has revised its position on recycled uranium 

contaminant ratios for the period 1961–1972. NIOSH to provide official written 

position on the revised ratios. (Related to SEC Issue 3; Slide 10)

 Findings 17 and 19 (correction factors for extremity beta 

exposures measured by film badges) Transferred

 July 28, 2017, WG meeting: Determined that the treatment of extremity doses is 

a program-wide issue currently under review by the SCPR. These finding to be 

transferred to the SCPR as part of the review of ORAUT-OTIB-0013 and closed 

as they relate to the Fernald TBD review.

18
Post-SEC Thorium Methods

 1979–1989:

 Monitored workers: use individual Mobile in Vivo Radiation 

Monitoring Laboratory (MIVRML) results

 Unmonitored workers: coworker intakes developed from 

MIVRML results

 1990–1994: 

 Monitored workers: use individual In Vivo Examination Center 

(IVEC) monitoring records

 Unmonitored workers: assign 10% of the derived air 

concentration (DAC) to all “radiological workers”

 1995–2006:

 Monitored workers: use individual IVEC results or BZ data as 

appropriate

 Unmonitored workers: no coworker dose assignment

19
Post-SEC Thorium Review

 Findings 1, 3, and 5: NIOSH to assign unmonitored thorium intakes to 

all radiological workers (1979–1994)

 July 28, 2017, WG meeting: WG recommends closure

 Finding 2: Intake Assignment

 SC&A recommended assignment of the 95th percentile to all radiological workers

 Fernald Work Group determined the 50th percentile with associated GSD is sufficient 

for most radiological workers

 95th Percentile Exceptions: workers who submitted baseline fecal sampling and 

workers employed by IT Corporation (subcontractor handling repackaging activities)

 July 28, 2017, WG meeting: WG recommends closure

 Finding 4: NIOSH to investigate use of higher Class Y DAC value for 

1990–1994 instead of currently proposed of Class W DAC for 

application of 10% DAC values used in unmonitored thorium dose 

reconstruction and provide official written position on issue

 July 28, 2017, WG meeting: In Progress

20
Post-SEC Thorium Review (cont.)

 Observation 1: In vivo monitoring program focused on high exposure 

potential (primarily uranium) jobs such as the chemical operators. No 

action required.

 Observation 2: Workers with positive in vivo results for thorium 

daughters (Pb-212/Ac-228) were resampled 10 times as often as rest of 

monitored population. No action required.

 Observation 3: SC&A concurs with the following claimant-favorable 

assumptions discussed at December 2014 WG meeting; No action 

required.

 Triple separation of thorium prior to intake

 Bias adjustment for chest counts of Ac-228 and Pb-212

 Criteria for unsupported radium exposure (see Post-SEC Thorium Finding 7)

 Observation 4: Notes that review of in vivo coworker distributions not 

performed at the time of review due to SEC discussions of timeweighted OPOS (TWOPOS) methods. No action required.

21
Post-SEC Thorium Review (cont.)

 Observation 5: Review of 22 unmonitored claimants (1990–

1994) indicated chronic exposure to thorium above 10% of the 

DAC is highly unlikely. No action required. 

 Observation 6: SC&A requested clarification on breathing zone 

“codes” used to identify thorium results. These location codes 

are discussed in Attachment E of the internal dose TBD update. 

No action required.

 Observation 7: Temporal collection and measurement criteria 

for BZ samples not apparent in the Fernald database. NIOSH 

provided additional information specifying that BZ data were 

collected on a daily basis but generally reported on a weekly 

basis. No action required. 

22
Thoron and Unsupported Radium

 NIOSH to investigate modeling of Building 65 thoron 

exposures in lieu of current site-wide model and provide 

official position on assumed occupancy factors for thoron 

exposure (subject of SC&A Finding 6)

 July 28, 2017, WG meeting: In Progress

 NIOSH to assign intakes of unsupported radium only in 

the rare case where the in vivo result for Ac-228 is a 

factor of 1.5 or higher than the associated Pb-212 result 

(subject of SC&A Finding 7)

 July 28, 2017, WG meeting: WG recommends closure

23
Uranium Coworker Model

 Methods developed in OTIB-0078, Rev. 03, and 

integrated into Attachment C of Fernald internal TBD

 Uranium intakes derived using 400,000+ bioassay 

results

 Unmonitored intake assignment

 All prime contract workers 1952–2006

 All construction trade subcontract workers 1984–2006a

(SEC-00046 established for subcontractors 1951–1983) 

a SC&A is not clear as to whether NIOSH intends to develop a separate coworker model for the transitional 

period from 1984 to 1985.

24
Uranium Coworker Model (cont.)

 SC&A Review of OTIB-0078 (2 findings)

Finding 1: Treatment of negative and zero 

bioassay results is inconsistent with guidance 

in ORAUT-RPRT-0053.

Finding 1 Resolution: Future revisions of the 

coworker model will use RPRT-0053 

methods. Effect likely not significant. 

 July 28, 2017, WG meeting: WG recommends 

this finding be put In Abeyance.

25
Uranium Coworker Model (cont.)

 SC&A Review of OTIB-0078 (2 findings)

Finding 2: Paired bioassay measurements 

for the same worker are different by 1–3 

orders of magnitude on the same day.

Finding 2 Resolution: NIOSH investigation 

determined the higher result was correct, and 

the lower results were removed from analysis.

 July 28, 2017, WG meeting: WG recommends 

closure.

26
Uranium Coworker Model (cont.)

 SC&A Review of OTIB-0078 (6 observations)

 Observation 1: SC&A could not recreate NIOSH’s calculation 

for some years in the late 1980s and early 1990s. 

 Resolution: SC&A and NIOSH exchanged calculation files and found that 

different procedures were used. NIOSH used correct procedure for those 

years. WG recommends closure.

 Observation 2: As expected, use of TWOPOS methods reduced 

the variability in derived distributions but did not significantly 

affect the geometric mean.

 Resolution: TWOPOS methods behaved as expected. WG recommends 

closure.

27
Uranium Coworker Model (cont.)

 SC&A Review of OTIB-0078 (6 observations)

 Observations 3–6: additional information in bioassay database 

“comments column” was not utilized in coworker calculations, 

including:

 Reported analytical results below control limit (Obs. 3)

 Notations that sample represents a pre-employment sample (Obs. 4)

 Indications of contaminated or otherwise invalid samples (Obs. 5)

 Identification of solubility type and intake route (Obs. 6)

 NIOSH acknowledges that in future revisions such comments in 

the Fernald database will be considered.

 WG recommends Observations 3–5 be put In Abeyance until future 

revisions. The effect on overall doses is not likely to be significant (low 

priority).

 The accuracy of information designating solubility type and intake route 

could not be confirmed, thus will not be used. WG recommends closure of 

Observation 6.

28
Path Forward – Site Profile Review

 NIOSH to provide official written positions on uranium- and radiumpoor raffinates (Findings 7, 8) and recycled uranium (Findings 9, 

10). 

 NIOSH to provide official written position on use of higher Class Y 

DAC value for 1990–1994 instead of Class W DAC for application of 

10% DAC values used in unmonitored thorium dose reconstruction 

and provide official written position on issue (post-SEC thorium 

Finding 4).

 NIOSH to investigate modeling Building 65 thoron exposures in lieu 

of current site-wide model and provide official position on assumed 

occupancy factors for thoron exposure (thoron, Finding 6).

 Schedule WG meeting to disposition active findings. Await future 

revision of TBD-5 to disposition issues in abeyance.

29
Questions

30