Fernald SEC Petition Revie

SC&A Status Update since Advisory Board Mee

August 23-25, 2011 in Richland, Washingt

Presented by John Stiver, SC&A

Presented to the Advisory Board on Radiatio

Worker Health

Full Board Meeting Held in Tampa, Florid

December 7-8, 2011
Work Group Review: Overvie

• April 19, 2006: SEC Petition qualified 

– “All employees who worked in all facilities at the Feed Materials Prod

Center (FMPC) in Fernald, Ohio, from Jan 1, 1951 through Dec 31, 

• Nov 3, 2006: NIOSH Evaluation Report issued 

– “NIOSH found no part of the class under evaluation for which it cann

radiation doses with sufficient accuracy.” 

• Nov 10, 2006: SC&A Site Profile Review • July 2, 2007: SC&A SEC PER Review • August 2007 

 August 2011: Eleven Work Group meetings 

• May 24, 2011, ABRWH Meeting: SC&A presents detailed summ

issues (as of April 2011) 

• One final WG meeting to be scheduled before February Board m

– SC&A believes that the Work Group can soon reach closure on the r

SEC issues 

• Move to SP discussions or bring before the Board for SEC determination 
Work Group SEC Issues

1. Coworker Model for Uranium Internal Exposures – open 2. Validation of the HIS-20 database – closed* 3. Recycled Uranium (RU) – open 

4. Use of radon breath data for reconstructing doses from inhala

226 and Th-230 – closed* 

5. Review of radon emissions from the K-65 silos and associate

- moved to site profile discussions 

6. Reconstruction of internal exposures from inhalation of Th-23

6A: DWE Data (1953 – 1967) – closed* 6B: Chest Counts (1968 – 1989) - open 

7. Recycled Thorium (RT) – new issue 

Identified in SRS discussions (August 2011) as potentially significaPreliminary investigations suggest this may be tractable for Fernald 

(* recommended by SC&A) 
Open Issue (#1): Co-worker Model for Uranium 

Internal Exposures

Description of Issue – Concerns regarding the completeness and adequacy of the urbioassay data available for dose reconstruction and supporting Fernald internal dosimetry co-worker model (OTIB -0078, dateNovember 6, 2007) Status of Issue – Resolved except for matters related to the applicability of the cmodel to Fernald construction workers Open action Items – NIOSH to perform an analysis of construction worker (CW) vsuranium bioassay data for TIB-0078 and deliver a report • Report delivered November 4, 2011 SC&A is reviewing the report and will prepare a response (befWG meeting) 
Issue #1: Co-worker Model for Uranium Interna

Exposures, concluded

Preliminary SC&A Observations – • NIOSH concluded that most of the “Type 50” bioassay records in 

are for contractors 

• These "special" records were not included in the original coworke

because they were presumed incident-related 

• New analysis: when these records are considered, the coworker m

estimates go up by a factor around 1.25 or 1.6, depending whetheor quarterly data 

• Not clear if NIOSH is comparing the construction workers as a gro

group of non-construction workers or added in the type 50 records earlier model. The "pooled" data would be about 1.25 as high as tmodel 

• If pooled, data for construction workers ALONE would be much highe

factors they found. How much higher depends on the relative sampl

• The paper contains no details of the analysis, only a graph with th

results 

• SC&A believes that NIOSH should provide a new revision with de

sample sizes, fitted distributions by time periods) 
Open Issue (#3): Recycled Uranium (R

Description of Issue: Concern that default concentrations of Pu-239, Nother isotopes associated with RU at Fernald may not be bounding for of worker activities, buildings, and time periods. Status of issue: Numerous white papers have been exchanged where provides its technical basis in support of its default values and SC&A preasons it believes that the default values may not be bounding for all time periods. Recap: August 11, 2011, Work Group Meeting New NIOSH Position on 

1953-1960: Proposes no RU constituent intakes 1961-1972: Proposes “original” defaults 

Pu-239 (100 ppb U) Np-237 (3500 ppb U) Tc-99 (9000 ppb U) 

1973-1989: Proposes increased default values (value, basis) 

Factor of 4 for Pu-239 (100 ppb U 

 400 ppb U) (Subgroup 8; MgF2) 

Factor of 3 for Np-237 (3500 ppb U 

 11,000 ppb U) (Subgroup 11; Waste Re

Factor of 2 for Tc-99 (9000 ppb U 

 20,000 ppb U) (Subgroup 6B; LEU produ

Based principally on MgF2 concentration in metal reduction (Plant 5) 

 highes

worker exposures 
Issue #3: Recycled Uranium - continu

SC&A position on new proposed NIOSH default values (August 201

1953-1960: • This period can be bounded (site profile); however, SC&A believes 

of zero may not be adequate in an SEC context 

1961-1972: • This period can be bounded (site profile); questions remain as to w

should be (original vs. some higher value) 

• Impact of MgF2 concentration with low feed levels – factor of 10 increa

appears to support 100 ppb chronic intake as bounding 

1973-1989: • Proposed higher defaults; probably bounding for the highest contin

subgroup of workers (Plant 5 metal workers and associated millwri

• Subgroup 10A feed concentrations could have impacted handlers a

blenders; also indirect exposures (bystander effect) (SEC issue 19785); 1986-1989 – good HP/IH program) 

• Small subset of workers but cannot identify based on work records 

• Intermittent exposures - covered by 400 ppb chronic intake? Intervals 

NIOSH Action Item: quantify down-blending intervals; assess impaSC&A action item: review NIOSH assessment 
Issue #3: Recycled Uranium - conclu

NIOSH “Downblender” assessment delivered November 2011 “Rationale for 400 ppb U Pu for 10A Process Stream at Fernald,” N2011 (Rich) 

Preliminary SC&A Observations • Estimates that any single worker would have spent at most 8 perce

annual work hours handling unblended POOS* (Group 10A) mater

• No data located that defined the down-blending and front-end hand

• However, can narrow to 1982-1985 timeframe, based on process know

• Relies on documented time to repackage 5 hoppers into drums in A

(SRDB 33730) and assumes sufficiently bounding for subsequent s

• Relies on unsubstantiated assumptions regarding shift time and nu

hoppers handled ( 8 hoppers > 400 ppb measured Pu) to reach 8% 

• Does not consider variability in measured Pu content/hopper (up to a fa

on DOE mass balance reports) 

• Time fraction could be higher based on reasonable alternative assump

hoppers considered, 8-hour shifts) 

• Nonetheless, SC&A’s initial impression is that the problem is t

SC&A to prepare response for Work Group prior to next Board mee*Plutonium Out Of Specification 
Open Issue (#6B) Use of Chest Counts to Reco

Th-232 Intakes (1968-1989) 

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

exposures (1968 -1989) 

• No DWE data after MIVRML introduced in 1968 – therefore compl

dependent on integrity of chest count data thereafter 

• SC&A believes that large uncertainties in data may render them inStatus of issue: White papers exchanged; issue first discussed 

the April 19, 2011, Work Group meeting 

• August 11, 2011, Work Group meeting: NIOSH to provide formal r

SC&A concerns regarding data adequacy and completeness 

• Responses delivered in November 2011 

• “Response to SC&A Response to NIOSH White Paper on FMPC MIVRML 

• “Response to SC&A Report on In-Vivo Thorium Coworker Model Data Com

• SC&A reviewing NIOSH responses and will provide final response for 

prior to next Board meeting 
Issue #6B: Use of Chest Counts to Reconstr

Th-232 Intakes (1968-1989), continued 

Recap: SC&A Concerns - Data Adequacy 

1968–1978: Reported in milligrams (mg) thorium (period of thorium proc

• MIVRML method appropriate for screening; not quantitative • Questionable calibration source used to derive MDL - contaminated with R• Questionable method to evaluate age of source and transform Ac-228/Pb

mg Th-232 – No raw data, just mg thorium reported 

• Uncertainty in age of source(s) at time(s) of intake (factor of ab

system using Pb-212; orders of magnitude if Ac-228 used) 

• Examples indicate Ac-228 used – very sensitive to age of source 

• Uncertainties in the resident time in the lung (progeny in-growth and trans

2.5 or more) 

• Predates OTIB-0044 (data less than MDL) • Inconsistencies between mg Th-232 and nCi Pb-212 for period of overlap 

mg Th-232 correspond to negative Pb-212 results (SC&A white paper – J

• Data for individual workers inconsistent with biokinetic processes (SC&A M

April 6, 2011) 

• Large variability and uncertainty in mg Th-232 data and lack of knowle

derivation may preclude ability to bound intakes 1968 - 1978 (SEC iss
Issue #6B: Use of Chest Counts to Reconstr

Th-232 Intakes (1968-1989), continued 

Recap: SC&A concerns - Data Adequacy, concluded 

1979–1988: Reported in nCi thorium (based on Pb-212 and Ac-2

stewardship) 

• Measurement variability (nCi Pb-212 and nCi Ac-228) on derived 

example - factor of about 2) 

• Uncertainties in the resident time in the lung (progeny in-growth/

• Predates OTIB-0044 (data less than MDL) • Uncertainties in the REMAB phantom (up to a factor of 3, pre-19

• Equilibrium factor (EF) of 0.42 for Pb-212 measurements based 

system (no translocation out of lung) 

• Experimental data indicate EF could be lower 

• Raw data are available - nCi thorium data may be adequate to 

intakes (site profile) 

• NIOSH coworker model uses a GSD of 7 

• Does not appear to address measurement uncertainties • Possibly adequate when applied to a distribution of results for multip

year, but not quantified 
Issue #6B: Use of Chest Counts to Reconst

Th-232 Intakes (1968-1989), continued 

Preliminary SC&A Observations: Response to SC&A Response to NI

Paper on FMPC MIVRML Calibration” (data adequacy) 

• General Issue #1: Large variability and uncertainty in mg Th-232 

of knowledge on derivation 

• Original SC&A Position 

• Large uncertainties and imprecisions in the data may render them inadeq

intakes 

• NIOSH position 

• SC&A arguments surrounding the lack of usefulness of the thorium lung c

to large uncertainties in the data are invalid 

• Large uncertainties in source data result in larger GSDs in model 

• Large proportion of sub-MDL data indicative of minimal exposure potentia

• SC&A Observation 

• SC&A’s concerns regarding disequilibrium of thorium source term(s) in ab

for 1968-1978 stand (factor of 200 for Ac-228 measurements) 

• High MDL indicative of limitations in the counting system. Still has signific

potential at sub-MDL intakes (MDL intakes can result in Sv-level organ do

• NIOSH model uses a GSD of 3 based on spread of all annual data – does 

uncertainties in individual measurements 
Issue #6B: Use of Chest Counts to Reconstr

Th-232 Intakes (1968-1989), continued 

Preliminary SC&A Observations: Response to SC&A Respons

White Paper on FMPC MIVRML Calibration” (data adequac

• General Issue #2: Appropriateness of MIVRML (Y-12) meth

quantitative estimates of thorium intake (SRDB 011596) 

• Original SC&A Position 

• The method used to estimate thorium burdens in mg carries man

and should only be used for qualitative assumptions about thoriu

• NIOSH position 

• NIOSH does not agree with SC&A that the in-vivo counting data 

for screening (selected quotes from SRDB 011596) 

• Cites SC&A data completeness paper as evidence of tacit accep

• SC&A Observation 

• SC&A’s position stands on limitations of the Y-12 method (e.g., p

SRDB 011596) 

• SC&A completeness study based on assumption of adequate da

(completeness and adequacy studies done in parallel) 
Issue #6B: Use of Chest Counts to Reconst

Th-232 Intakes (1968-1989), continued 

Preliminary SC&A Observations: Response to SC&A Respons

White Paper on FMPC MIVRML Calibration” (data adequac

• SC&A Summary Position 

• NIOSH wants to use the results in mg of thorium without know

those results mean 

• Do not know which daughter (Ac-228 or Pb-212) was measured • Do not know how the results from the daughters were transform

lung burdens 

• Do not know the sensitivity of the measurements • Few individuals had results in mg of thorium and results in Pb-21

results do not match, using NIOSH assumptions 

• Weldon Springs precedent: (pp 55-56 of NIOSH ER) disregar

counts due to uncertainties as to when intakes occurred (dise

• “The cases where such use of the in-vivo counts would be neces

limited to those with very specific circumstances and information

• SEC Issue remains for mg thorium data (1968-1978) 
Issue #6B: Use of Chest Counts to Recons

Th-232 Intakes (1968-1989), continued 

Recap: SC&A Concerns - Data Completeness (presuming adequate dSC&A tasking – formal response (February and April 2011 Work Group • Are thorium workers and their associated exposure potential adequately rep

dataset? 

• If not, do chemical operators provide a reasonable surrogate for thorium wo

a coworker model? 

• Were the workers with the highest exposure potential to thorium targeted m

for monitoring? 

Preliminary SC&A Observations: “Response to SC&A Report on In-Vi

Coworker Model Data Completeness” (1968-1978; mg thorium data

• Issue #1: Identification of thorium workers and their relative exposu

• Original SC&A Position 

• Identified thorium workers in 1968 had higher recorded lung burdens than c

who were not associated with thorium work as well as the “all worker” grou

• To characterize subsequent years, a separate comparison was made whic

thorium worker population was constant (1968-1978) 

 reached similar co
Issue #6B: Use of Chest Counts to Recons

Th-232 Intakes (1968-1989), continued 

• Issue #1, continued 

• NIOSH position 

• Analyzed empirical 1968 data using the Kolmogorov-Smirnov (KS) test an

thorium workers identified in Starkey memo are not from a different paren

• Does not feel comparisons assuming a constant thorium worker populatio

• SC&A Observation: 

• SC&A agrees that thorium workers do not constitute an independent work

However, SC&A’s position remains that workers who handled thorium had exposure potential to thorium than workers who did not 

• SC&A feels the constancy assumption would only act to underestimate th

worker exposures and so the comparisons are meaningful 

• Issue #2: Number of Positive Results Identified During the Product

• Original SC&A Position 

• Less than 3% of the chest counts (mg of Th) were at or above the stated 

questionable data set for developing a viable coworker model (MDL intakerem 

 Sv organ doses) 

• Percentage of samples >MDL for workers who handled thorium >non-thor

(7% vs. 3%) 
Issue #6B: Use of Chest Counts to Reconst

Th-232 Intakes (1968-1989), continued 

• Issue #2, continued 

• NIOSH position 

• Coworker models use uncensored data and so the number of records bel

irrelevant 

• SC&A Observation 

• NIOSH model predates OTIB-0044 and relies on OTIB-0095. Problem w

data <MDL rectified by OTIB-0044. If mg thorium data deemed adequate to update model (Site Profile) 

• Large proportion of lung burdens >MDL for “thorium workers” suggests tha

handled thorium had higher exposure potential than workers who did not 

• Issue #3: Monitoring Criteria for Inclusion in the MIVRML Lung Co

• Original SC&A Position 

• Aside from 1968, the thorium in-vivo monitoring program was not focused 

workers but rather on the much larger uranium operations at the site 

• Thorium chest counts are always coupled with uranium lung counts

always true 

• In-vivo monitoring showed no bias towards plants with thorium oper

appeared to concentrate on Plant 5 (no known thorium operations) 
Issue #6B: Use of Chest Counts to Reconst

Th-232 Intakes (1968-1989), concluded 

• Issue #3, continued 

• NIOSH position and SC&A Observation 

• Specific site interview indicates no preferential sampling was conducted fo

after 1968. “People chosen for lung counts were chosen for overall expos

necessarily thorium exposure potential” (SC&A agrees) 

• Concludes that there is no correlation between a worker’s monitoring fre

thorium lung burden (SC&A agrees) 

• Summary of SC&A position on data completeness (presuming ade

• In-vivo monitoring records for thorium are essentially complete 

• No significant chronological gaps were identified • No evidence that highest exposed worker population was systematically 

monitoring program 

• SC&A believes NIOSH should assign a sufficiently bounding intake ra

percentile) to assure claimant favorability 

• ORAUT 2008 provides no guidance as to how the coworker model should 

assure claimant favorability 

• New NIOSH response on data adequacy suggests lower bound of 50th pe

guidance is provided for determining an upper bound 
Recycled Thorium (new issue) 

• SC&A first became aware of receipts of recycled thorium at Fernald at the S

teleconference on August 12, 2011 

• SRDB review - hundreds of metric tons of recycled thorium were received a

mid-1960s to late 1970s (most from SRS) 

• Principal concern is exposures to U-233, U-232, Th-234, Pa-233, and fissio

during processing, handling, and storage of RT (similar to RU) 

• Previous investigations of thorium intakes have focused on proposed NIOS

models based on air sampling and chest count data (SEC issue #6) and intfrom raffinates (SEC issue #4) 

• Ability to reconstruct intakes of RT constituents is predicated on the veracity of th

coworker models (SEC issue) 

• Sparse data on source term configurations and periods of concern - may re

capture/review 

• Accommodating RT will likely result in changes to the TBD 

• Primary constituents of interest are uranium isotopes and progeny (U-232, U-233

• Fernald has an abundance of U bioassay data; principal concern will be external 

from U, Th progeny; U-232, U-233 n/p ratios) and bounding internal DCFs to acc

• SC&A to deliver a paper for discussion at the WG meeting before the next B
Summary

Issues remain to be dispositioned with NIOSH and • Work Group deferring action on recycled uranium for 1973 throu

pending SC&A response to NIOSH down-blender assessment 

– Quantified front-end handling intervals to bound periods during whi

blenders (and bystanders) may have been exposed to subgroup 10concentrations 

• Are new higher defaults bounding for those years when 10A materials h• If so, we can move this issue to Site Profile discussions? 

• Work Group deferring action on thorium chest count data (1968-

pending further assessment 

– SC&A to provide formal responses to NIOSH on the November 201

adequacy and completeness reports 

– SEC concerns remain (1968-1978) 

• SC&A to provide white paper on recycled thorium • SC&A believes that the remaining SEC issues should be resolve

final Work Group meeting 
Questions?