Fernald SEC Petition Revie

Status Update

Brad Clawson, Chair, Fernald Work Group 

John Stiver, SC&A Team

Presented to the Advisory Board on Radiation and Work

Idaho Falls, Idaho

July 16–17, 2013
Work Group Review: Overview

• April 19, 2006: SEC Petition qualified

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

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

• November 3, 2006: NIOSH Evaluation Report issued

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

estimate radiation doses with sufficient accuracy.”

• November 10, 2006: SC&A Site Profile Review

• July 2, 2007: SC&A SEC PER Review

• August 2007  July 2013: 16 Work Group meetings

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

issues (as of April 2011)

– O:\AB Document Review\Fernald\SC&A Work Products for SEC Issues Re
Status ‐ Work Group SEC Issue

1. Coworker Model for Uranium Internal Exposures – open2. Validation of the HIS‐20 database – closed*

3. Recycled Uranium (RU) – closed*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 associated 

‐ moved to site profile discussions

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

6A: DWE Data (1953–1967) – conditional closure**

6B: Chest Counts (1968–1989) – closed***

* Work Group recommendation.** New coworker model introduced by DCAS since closure recommendation in 2

*** SEC: 1968–1978 for all workers (based on mg thorium data). 1979–1989 mov

profile discussions March 2013 WG meeting.
Open Issue (#1): Coworker Model for Uranium 

Internal Exposures – Subcontractor Employee

Original Description of Issue – Concerns regarding the completeness and adequacy of the urbioassay data available for dose reconstruction and supporting Fernald internal dosimetry coworker model (OTIB-0078) Status of Issue – Numerous white paper exchanges and Work Group meeting dfrom inception to July 1, 2013, Work Group teleconference At July 1, 2013, Work Group teleconference, the Work Group motion to recommend to the Board that a class of workers comsubcontractor employees at Fernald from January 1, 1951, thrDecember 31, 1983, be added to the SEC 
Coworker Model for Uranium Internal Exposure

Subcontractor Employees, continued

Central Issues• Subcontractors were employed at Fernald from the beginning of 

in 1951

• Subcontractors were not included in the routine bioassay program 

when Westinghouse took over the M&O contract from NLO

• The uranium bioassay coworker model does not include subcontr

samples prior to 1986

• Prior to the March 2013 WG meeting, DCAS located 939 hardcop

records for about 180 subcontractors collected over a 9 ‐year per

1969 to 1985

• These uranium bioassay data are extremely limited and there are

data to make meaningful OPOS comparisons for these earlier yea

• SC&A observed bioassay records for a group of subcontractors fro

that appeared to be very high compared to the prime contractor 
Coworker Model for Uranium Internal Exposure

Subcontractor Employees, continued

March – July 2013 key activities and findings• As proof of principle, the WG asked DCAS to perform “best‐estimate” in

evaluations for these subcontractors using their data and compare this 

would have received from the 95th percentile of the coworker model

• The second aspect of this comparison exercise was for DCAS/ORAUT to 

subcontractor claimants from the pre‐1986 era with employment data

• If the best‐estimate intake values were all bounded by what would have 

assigned via the coworker model, this would be a very powerful piece o

that the surrogate data in the coworker model were appropriate for sub

• NIOSH’s response showed that depending on the solubility class, the 9

of the coworker model would bound intakes for some of the subcontrac

all

• SC&A observed that the NIOSH coworker doses for claimants extended 

the periods of bioassay intake, which biased results in favor of the cowo

• SC&A also observed that the assumptions used for the non‐claimants w

and constrained potential intake, again favoring the coworker model

• Even so, the comparison strongly suggests that the coworker model is n
1400000

12000001000000

800000600000400000200000

0

Type M DR integrated intake

pci Intake pCi Intake 2.E+07 2.E+07 1.E+07 1.E+07 1.E+07 8.E+06

6.E+064.E+062.E+060.E+00

Type S DR integrated intake

Coworker integrated intake

Coworker Model for Uranium Internal Exposure

Subcontractor Employees, continued
Coworker Model for Uranium Internal Exposures 

Subcontractor Employees, continued

March – July 2013 key activities and findings• At the July 1, 2013, WG teleconference, DCAS agreed that the uranium 

model was not bounding for the subcontractors prior to the mid ‐1980s

• It was determined that the hardcopy data supported a separate cowork

subcontractors in 1984 and 1985, but not prior

Table 1: Fernald CW Subcontractor Results in Hardcopy

Year No. of Individuals Results

1969 12 521971 13 851972 6 171973 3 41981 16 351983 38 1641984 82 2751985 67 3071986 79 370
Coworker Model for Uranium Internal Exposure

Subcontractor Employees, continued

March – July 2013 key activities and findings• Research revealed that uncontrolled subcontractor uranium exposure p

existed as early as mid‐1952 and likely since the beginning of uranium h

1951:

• (SRDB 3230, pg. 118) Dated August 7, 1952:

[Redacted] has the difficult problem of getting management and supervisors 

the fields of good housekeeping practices, general health and safety supervis

enforcement procedures which will insure proper control of uranium contam

hundreds of contractor and subcontractor personnel running around “loosareas. However, the sooner National Lead of Ohio management and the top 

of the construction contractor know the AEC requirements for health and saf

the sooner bad practices will be curtailed. [Emphasis added.]

• At July 1, 2013, WG teleconference, the WG passed a motion to recomm

Board that a class of workers comprising subcontractor employees at Fe

January 1, 1951, through December 31, 1983, be added to the SEC
Issue #6A: Reconstruction of Internal Exposures fro

Inhalation of Th‐232 (DWE Data)

• Description: Use of BZ and GA sampling data and associated d

weighted exposures (DWEs) to reconstruct Th‐232 intakes

• Central Issues

– Data Adequacy and Completeness

• Sufficient DWE Data to Bound Internal Doses from Th‐232 in 

buildings from 1954–1967

– Given Adequate Data, are NIOSH’s Proposed Methods Suffi

Robust to Reconstruct Doses in Accordance with 42 CFR 83 

Requirements?

• Status

– March 2008 – June 2013

• Numerous white papers exchanged• NIOSH produces 5 Revisions of the DWE Coworker Model
Review: Daily Weighted Exposure (DWE) Conce

• Introduced by AEC HASL in 1953• Monitoring concept was transferred to the FMPC staff; used at F

the beginning of site operations since 1954

• DWE reports ‐ summaries of data prepared by the FMPC Industr

and Safety (IH&S) staff for use by management

– Provided Estimate of Average Worker Exposure by Job Type

– Used to Assess and Control Radioactive Dust Levels in a Plan

assess intakes)

– Provided a Standardized Methodology through FMPC History

• Based on Gross Alpha Air Activity Concentration (AAC) Measurem

– Applicable to Workplace Alpha Emitters (U, RU, Th, U, and Th 
Review: DWE Description

• Time‐Weighted Alpha Air Concentration (AAC)

– Job‐ and Building‐specific

– Several Tasks per Job (3 to >20)

– High, Low, and Average AAC in dpm/m3 Reported 

Task Associated with a Job

– Time to Complete Each Task Reported

– Sample Type (BZ, GA)

• BZ – Most Job‐specific Tasks

• GA – Ambient, Typically Less Contributor to Do

cafeteria, washroom)
DWE Reports ‐ Summary

• Job‐Specific DWE Represents:

– Task‐weighted Average Air Concentration of Given 

Emitter (e.g., Th‐232)

– For Specific Day(s)

– For the Monitored Worker(s)

– Time Weighting is Crucial

• Link between the AAC at a location and time to 

worker exposure

• In Reality ‐ have a Distribution of DWEs for Workers in 

Job (key concept)

– There was Spatial and Temporal Variation in AAC E

by Any Given Worker

– No Uncertainty Analysis
DWE Uncertainty Analysis

Davis and Strom 2008 – Highlights

• Reviewed six HASL reports covering five sites that were visited between 1

to characterize radiological hazards arising from the use of U, U ore, Th, o

222 

• 63 job titles for which DWEs are reported. Each job title was held by 1 to 1

from a total of 165 employees across the sites 

• Job titles involve from 1 to 13 operations, and each operation is characteriz

air samples. A total of 428 air samples are reported. 

• A significant fraction of workers (i.e., 104 of 165, or 63%) were exposed ab

contemporary MACs 

• Focused on variability in observations as evidenced in the air sample data 

which dominates the DWA uncertainty 

• Sources of uncertainty and variability: 

– measurement uncertainty, variability, and mistakes in data processing and comm

the representativeness of air samples to what a worker actually breathed 

– Variability arises due to uncertainty in aerosol particle size distributions, process 

placement of air samplers, changes in ventilation 

• Ran Monte Carlo simulations to generate distributions of discrete DWE and 

fits to DWE 
Davis and Strom 2008 – Highlights (continue

• Log-normal fits allow for the possibility that exposures can be la

smaller than those actually observed 

• Upper 95th percentile of the GSD value is about 4, and the uppe

percentile is between 7 and 8. 

– Supports a GSD of 5 when a concentration measurement is ava

there is no information on uncertainty. 

• Using the distribution of all air samples from a plant without time 

or assignment to specific jobs does not produce a DWE or GSD representative of any individual worker for that site. 

• The means of unweighted site-wide average concentrations exc

DWAs for all workers in 60 of 63 cases. 

• The site-wide average concentration is a biased estimator of exp

it can be used in making compensation decisions when it is requfavorable to a claimant. 
Fernald Thorium Buildings and Timeline

Reference - White Paper on the Use of FMPC DWE Reports for Estimation of ChronicDaily Intake Rate, Rev. 3, Robert Morris, Oak Ridge Associated Universities Team, Cincinnat

Ohio. October 2010.
Fernald DWE Data and Coworker Models

• March 2008 – NIOSH Posted for Review

– 160 DWE Reports for the plants identified in the previous slide

– Spreadsheets with Sample DWE Data for Th‐232 Plants for 1955, 1966, Plant 

Sample data 

Data used

Plant Year Work

1 1955 12 4 1955 66 9 1955 11

Totals 19
Fernald DWE Data and Coworker Models

• March 2008 – June 2013

– Numerous white papers exchanged

– NIOSH produces five Revisions of the DWE Coworker Model

– March 2009 NIOSH CW Model Rev. 2

• Questionable statistical approach, unwarranted level of granularity (year, building

• July 2009: SC&A Review – 20 findings related to uncertainty and modeling approa

– October 2010: NIOSH CW Model Rev. 3

• Incorporated uncertainty from Davis and Strom (2008)

• Assigns the highest DWE for a given building in a given year to all workers in that 

combination with a GSD of 5

• SC&A agreed in principle with that approach, with the caveat that NIOSH demons

feasibility of implementation

– November 2012 – SC&A analysis demonstrates it was not possible to place w

given facility in a year

– June 2013 NIOSH CW Model Rev. 5 – Like Rev. 3, it is a one size model, but a

highest DWE for the entire site to all workers for each year of thorium produ

attempt to place workers in particular buildings)
Fernald DWE Data and Coworker Models (contin

Rev. 5 DCAS Coworker model uses limiting DWE for each 

Limiting Daily Weighted Exposure (MAC) for Plants and Years Where Thorium w

Location 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 19

Plant 1 N/A* 23.4 6.1 2.2 1.4 3.0 0.7 0.9 1.5 0.9 1.0 0

Plant 4 6.4 4.5 1.3 ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ 

Plant 6 ‐ ‐ ‐ ‐ ‐ 2.6 6.2 25.0 4.0 22.3 ‐ Plant 8 ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ 

Plant 9 N/A 215.1** N/A ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ 

Pilot Plant 5.9 N/A 2.0 ‐ ‐ ‐ ‐ ‐ ‐ ‐ 5.9 N

*N/A = No daily weighted exposure reports are available.

**The highest DWE value in 1955 was 686 MAC but included dust loads above the physiolo

level for unprotected breathing. Application of a respiratory protection factor would decrevalue to less than 20 MAC. 215 MAC was adopted as the limiting case since it involved job

physiological tolerance level for unprotected breathing and did not require a respiratory fa
Fernald DWE Data and Coworker Models (continu

NIOSH has Th air sampling data from the Pilot Plant from 1965 and 1967 and pla

the 95th % of BZ samples for each year and the higher for 1966. They would the

Plants 1 and 8 DWE and use the highest for that year

Year # Total Samples

Concentration (dpm/m3) Corresponding

Intake (nCi/d)

# Total

Thorium BZ

Samples

Concentration (dpm/m3) 

GM GSD

95th

Percentile GM GSD 95th Percentil

1964 63 31.8 4.1 330.1 (4.7 MAC) 1.04 16 43.7 2.4 574.3 (8.2 MAC1965 67 73.7 7.1 1852.4 (26.5 MAC) 5.82 21 117.0 2.4 484.6 (6.9 MA

19662 N/A

1967 61 69.8 4.1 705.5 (10.1 MAC) 2.22 43 118.2 3.7 1027.3 (14.7 MAC) 

*These values do not bound the current 95th percentile values presented in ‘Summary of Th

Rate Guidance DRAFT TO DCAS 05‐30‐13.docx’ found at [O:\AB Document Review\Fernald\

Mar03_2013 WG mtg\Item 10 Method for Using DWE]. Thus, Plants 1 and 8 DWEs are boun

[1] Per the NIOSH text document, they plan to use the 95th percentile of thorium breathing zone samples only.[2] NIOSH does not plan to use these data, but rather use the DWE values for the Stokes Furnace Operator in 19

roughly 5.85 MAC – 1.3 nCi/d).

[3] NIOSH plans to use the higher of the DWE values for 1965 or 1967 for this year unless bounded by Plant 1.
Fernald DWE Data and Coworker Mode

• July 1, 2013, WG teleconference meeting

– WG requested summary data for limiting DWEs proposed in Rev. 5 co

# of Job Types

Evaluated in Limiting # of DWE’s for Duration of Limiting Plan

Year Thorium Plants Plant/DWE Limiting Plant Study 

1954 14 Plant 4 14 Unspecified

1955 59 Plant 9 32 5/17/1955 – 10/31/1955 

1956 51 Plant 1 20 Jan‐Dec 1956 

1957 22 Plant 1 22 Unspecified

1958 12 Plant 1 12 Aug – Nov 1958 

1959 67 Plant 1 12 8/26/1959 – 10/1/1959 

1960 70 Plant 6 58 3/1/1960 – 6/22/1960 

1961 82 Plant 6 70 Aug‐Oct 1961 

1962 83 Plant 6 72 Feb‐Mar 1962 

1963 81 Plant 6 72 Oct‐Nov 1963 

1964 19 Pilot Plant 2 3/1/1964 – 10/31/1964 

1965 16 Plant 1 16 Feb‐Sept 1965 1966 29 Plant 8 14 Unspecified

1967 17 Plant 1 17 Unspecified

Average 44 31 
Summary – Issue 6A Th‐232 Coworker Model for 195

Based on DWE

• DWE data adequacy and completeness do not appear to be a p

thorium buildings from 1954–1967 for purpose of constructing 

coworker model for Th‐232

– Job types appear to be well represented

– Sufficient DWEs exist for each year and limiting plant to ascertain 

job type

– GSD of 5 accounts for uncertainties– Air dust study duration per year available for 10 of 14 years

• Ranges from 28 to 356 days, average of 135 days

– 1965–1967: “proof of concept” comparison shows that 95th perc

on DWE data from Plants 1 and 8 are bounding

– High dust loads identified in historic communications reflected in 

• Does not appear to be systematic suppression of high results

• Dust studies used for process improvement, not intake assessment
SUMMARY

• Work Group recommends full Advisory Board review and actio

dose reconstructability of subcontractor exposure at Fernald fo

– Uranium from 1951 through 1983, when the uranium bioassay co

model is not bounding for subcontractors

• Work Group recommends acceptance of NIOSH’s ability to reco

thorium exposures from 1954 through 1967 based on the thor

coworker model based on DWE.

• Completes remaining SEC issues for petition period.

• Work Group will continue to focus on resolving remaining site p

issues.
Questions?