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ISSUES RESOLUTION MATRIX FOR WR GRACE & COMPANY in Erwin, Tennessee SITE PROFILE

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applicability within the requirements of 42 CFR 82. 

Finding

Number 

Report 

Section Finding Description NIOSH Response

1 3 Accuracy and completeness of bioassay 

records not addressed. 

The accuracy and completeness of the 

recorded bioassay data have not previously 

been addressed by either DOE or NIOSH as 

part of a routine “verification and validation” 

(V&V) database review. SC&A performed a 

preliminary scan of the WRG DOE files for 

a small sampling of claimants and did not 

identify any outstanding issues. However, a 

broader and more detailed survey should be 

conducted that would determine if workers 

who should have been monitored because of 

job title (i.e., chemical operator, productionline operator, etc.) and/or location (i.e., 

production buildings, waste facilities, burial 

grounds, etc.) have recorded bioassay data 

for the corresponding periods when working 

in these areas.

The available bioassay data was extensively reviewed by NIOSH both for 

development of the TBD and evaluation of the SEC petition, although there 

are a number of additional claims added since that time.

NIOSH agrees that data review and analysis needs to be completed for the 

adequacy of claimant uranium bioassay data during the period of burial 

ground remediation. The review should focus on job titles, work locations 

and bioassay data to determine if those who should have been monitored 

based on job responsibilities were monitored. 

Derived default intakes for uranium for the operational and residual period 

currently exist and are based on actual air concentration data at WR Grace 

during the operational period, so no further development of a uranium 

coworker model is necessary. Based on NOCTS records, uranium bioassay 

began in late 1964, and it is quite extensive in claimant records from that 

point, with few exceptions. No bioassay has been found prior to that date, so 

it is already known to be deficient prior to late 1964. Default intakes are 

provided in the TBD for unmonitored periods. The TBD also provides 

default intakes that are to be used for the residual contamination period, with 

the exception for workers performing remediation of the burial grounds. 

Other than the period of burial ground remediation, review of adequacy of 

claimant uranium bioassay data is not needed or useful. 

Plutonium bioassay data is available for some workers starting in 1967. The 

available plutonium bioassay data will be reviewed and intakes are to be 

assessed (see Finding #3 response). 

Thorium bioassay data is not available for claimants, nor known to exist, 

during the AWE period, which is the basis for the SEC, from 1958-1970. 

Therefore, additional review of claimant data for thorium bioassay data is not 

needed.
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2 Insufficient uranium bioassay/intake data. 

If a worker’s uranium bioassay data are not 

available, the TBD recommends on page 25 

that the intake values in Table 3-15 be used 

to assign unmonitored dose during the 

operational period 1958–1970. There has 

been no documentation or substantiation of 

the appropriateness of using a 1961 air 

concentration data point for operating 

conditions at WRG during the entire 

operational period. Additional investigation 

of the use of the 1961 data for 1958–1970 is 

needed.

The methodology in the TBD provides a claimant favorable approach, as 

described below. 

The 1.71 x 103 pCi/day uranium inhalation intake in Table 3-15 of the TBD is 

based on exposure to an air concentration of 578.38 dpm/m3 for 2,000 hours 

per year. The air concentration is the 95th confidence level of the 1961 

breathing zone (BZ) samples from SRDB Ref ID 11771, as shown in TBD 

Table 3-8. It is used to calculate an upper bound internal exposure during the 

operational period. This is the basis for the default uranium intakes that are 

assigned during the operational period (1958-1970) for usage only if no 

uranium bioassay exists for an EE.

SRDB Ref ID 11771 also has results from November 1959 airborne dust 

surveys during operations at WR Grace. It states “Only two operations 

produce significant dust concentrations. The average concentration at 

digester charging, an unventilated operation, is 170 dpm/m3

. The average 

concentration at the dry box operation is 280 dpm/m3

.

The BZ sample results from the 1959 and 1961 surveys were not personal air 

samplers and are not directly representative of average worker exposures. 

However, both the 1959 and 1961 survey reports also included estimates of 

the workers’ average daily weighted exposures. The maximum reported

average daily weighted worker exposures from those two studies was 170 

dpm/m3

. The various results are shown in Tables 3-4 through 3-9 of the TBD.

NIOSH agrees with SC&A’s comment that the use of the single default 

intake value in the TBD is not representative of all exposures; however, given 

the limited data available and the uncertainty in selecting an appropriate value 

for a particular dose reconstruction, the assumption of 1.71E+3 pCi/d 

inhalation intake in Table 3-15 is a claimant favorable realistic bounding 

intake for operators. Further evaluation would not likely result in a higher 

default bounding intake. However, NIOSH will evaluate the intakes in Table 

3-15 to provide more realistic intakes for those workers who would not have 

been routinely exposed to such high levels of uranium.
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3 Use of operational-period plutonium 

results but not residual-period plutonium 

results, and not estimating non-bioassayed

workers’ plutonium doses during either 

period, are not consistent with the Special 

Exposure Cohort (SEC). 

The SEC was not based on lack of 

plutonium data, and it has not been 

documented that plutonium was not AEC 

weapons-related (and indications are that it 

could have been, in any case). Therefore, 

plutonium DR during the operational 

period should be included in the DR 

protocol, as it was for uranium, with 

provisions (such as using a coworker model) 

to bridge gaps in bioassays, or to compensate 

for lack of bioassays. Additionally, not 

assigning plutonium dose during the 

residual period assumes that all legacy 

plutonium from the operational period is still 

undisturbed in storage, burial grounds, 

ponds, buildings, duct work, etc., and creates 

no significant exposure hazard. However, 

this is not the situation during the residual 

period. Therefore, it appears that to 

substantiate that plutonium processed at 

WRG was not used in the AEC weapons 

program (and hence not to be included in the 

residual period as recommended in the 

TBD), NIOSH would need to locate 

government documents outside of the 

WRG/NFS company that would verify the 

origin, destination, and ultimate use of the 

plutonium material processed at the WRG 

facility during the operational period.

After additional review of the scope of the plutonium work at W. R. Grace, 

NIOSH concludes that dose received from plutonium work at W.R. Grace 

should be included in dose reconstructions. Therefore, an assessment of 

plutonium exposures from both the AWE and the residual contamination 

periods will be performed for a revision to the TBD in order to determine an 

appropriate methodology and if data capture efforts are needed. This 

methodology will assess the quantity of plutonium processed in order to 

evaluate unmonitored exposures, as well as reviewing existing claims with 

plutonium bioassay.
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4 Lack of neutron dose assignment. 

SC&A did not locate any recorded neutron 

doses in the claimants’ files reviewed to 

date. The TBD concludes (page 28) that 

there were potential neutron exposures, but 

“No attempt should be made to estimate 

neutron dose for workers not monitored for 

neutrons during the operational period.” 

Site profiles for other uranium- and 

plutonium-handling facilities incorporate 

neutron doses in the DR process, usually 

using the neutron-to-photon ratio (n/p) 

method, for workers potentially exposed to 

neutrons. Further investigation of the 

potential neutron exposures and methods 

to assign appropriate neutron doses is 

needed for the WRG facility.

NIOSH agrees that further investigation is necessary. The timeframe for 

when neutrons are assigned to be based on the results of the assessment of 

plutonium exposures from both the AWE and the residual contamination 

periods, (1958-March 1, 2011) from Issue #3. The NP ratio(s) from the 

assessment can be used to estimate neutron dose from the WR Grace source 

term.

5 Lack of dosimetry calibration 

knowledge. 

Because of the lack of information indicating 

otherwise, it appears that the dosimeters for 

WGR workers were read and recorded by 

outside vendors, with WRG depending on 

the processing companies to provide the 

correct correlation between the various 

radiation fields at WRG and the vendor’s 

calibration. It needs to be determined if any 

field measurements of the radiation energy 

spectra were made, and what calibration 

source(s) were used by the vendors. 

Dosimeters calibrated using higher-energy 

sources, such as Co-60, may not have 

correctly responded to the lower-energy 

photons from the various radionuclides 

present at WRG. Therefore, a correction 

It is agreed that there is limited information in the SRDB to address this 

finding. SRDB Ref ID: 23570 provides general Landauer information and 

the accuracy of the Landauer results are assumed to be sufficient for 

calculating doses. No additional data capture efforts are necessary. 
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factor may be needed, especially for 

determining the dose to skin and shallow 

organs.

6 Onsite medical x-ray exams not 

substantiated. 

It has not been substantiated that x-ray

exams were performed onsite at the WRG 

facility during the AEC operational period of 

1958–1970. Therefore, assigning offsite xray exams may not be consistent with 

ORAUT-OTIB-0079 (ORAUT 2011d) if the 

exams were performed offsite. While the 

TBD recommendations are claimant 

favorable, to ensure consistency with other 

site profiles, this is an area that needs further 

verification.

We have no definitive information of where occupational medical X-rays 

were taken during the operational period, (1958-1970). However, NIOSH 

does not believe that additional research or further verification is necessary. 

ORAUT-OTIB-0079, directs us to assume that X-rays were performed on site 

until substantive evidence exists to show otherwise. 

We currently have limited information regarding occupational medical Xrays for WR Grace, Erwin, Tennessee. SRDB Reference ID 11775, p. 5 of a 

Nuclear Safety Review (unknown year, but Davison era), indicates that a 

physician is utilized for the medical program at WR Grace which includes 

pre-employment, annual and termination physicals, for which the physicals 

include a pre-employment X-ray, but not for annual X-rays. SRDB 

Reference ID 41325, p. 8 (Worker Outreach Meeting from 2005) – discusses 

that annual PA chest X-rays were performed in the early years.

Due to the limited amount of information, the claimant favorable defaults 

established by the project are appropriate. The defaults are the assumption of 

annual PA chest X-rays during the operational period, (e.g., January 1, 1958 -

December 31, 1970). Because these are claimant favorable assumptions, no 

further action should be necessary.

Additionally, in order to provide clarification, it is recommended that the 

following be addressed in the next TBD revision:

1. SRDB Reference ID 11775, pg. 5 states that pre-employment, annual 

and termination physicals were done. However, it also states that xrays were NOT taken at the annual physical. This does not appear to 

have been included in the TBD.

2. Although the TBD references OTIB 79, the TBD should state that the 

x-rays are assumed to have been performed on site per the direction in 

OTIB 79, since no evidence to the contrary exists. See #3 below, 
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though. The TBD cites OTIB 79 as a justification for assigning Xrays, but makes no mention of onsite or offsite.

3. Include references not currently cited. For example, the worker 

outreach meeting from April 2011, SRDB Reference ID# 117711, p. 

20 is not referenced in the TBD published in Sept. 2011. 

7 The 2011 TBD does not adequately 

cover environmental doses. 

The methods for estimating dose in the 

TBD do not account for airborne 

radioactive materials that were generated 

by the cleanup and processing of waste 

from the ponds and burial grounds during 

the residual period to which monitored, as 

well as unmonitored, non-burial ground 

workers may have been exposed. These 

non-burial grounds workers may still have 

been exposed to environmental radioactive 

materials from the cleanup operations 

during the residual period. 

The internal and external environmental 

exposures throughout the site during both 

the AEC period (1958–1970) and from the 

cleanup of the AEC legacy materials 

during the period 1971–present are not 

adequately addressed.

For the operational period (1958-1970), it is reasonable to continue 

reconstructing doses based on available bioassay results and to assign default 

uranium intakes per Section 3.4 of the TBD for unmonitored uranium 

workers. Section 6 of the TBD, is considered to be appropriate: “It is not 

necessary to include an environmental dose component for W.R. Grace 

worker dose because all workers are assumed to have been exposed to 

operational conditions, and dose has been assigned accordingly.” (Also refer 

to response to Finding 2 on derivation of uranium default intakes and 

response to Finding 3 on not needing a plutonium coworker model for 

unmonitored plutonium workers). Additionally, the operational period 

(1958-1970) has a SEC for thorium.

Data capture efforts are recommended in order to properly address this 

finding for the remediation portion (1991-March 2011), of the residual period 

at WR Grace. Workers (in their interviews) indicate that both lapel SRDB 

Ref ID: 98196 and boundary air samples were taken SRDB Ref ID: 98200

and 117711 in 400 and 410 where the remediation was done. The main two 

buildings used in the Ponds 1, 2, 3, 4 and the Burial ground D&D work were 

the 400 and the 410 Buildings. Therefore, data capture efforts are needed to 

include all survey and air data post 1990 for 400 and 410 buildings and/or 

ponds/burial grounds areas to determine if the derivation of environmental 

doses are warranted. 
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Seconda

ry 

Finding 

A

3 Table 3-15, Table 5-2, and Table 5-3 

based on 365 days instead of 250 days 

per year. 

SC&A found that Tables 3-10 and 3-11 on 

page 22 of the TBD are based on 250 

days/year (i.e., 2,000 hours/year × 1 day/8 

hours = 250 days/year); However, Table 3-

15 on page 26, Table 5-2 on page 33, and 

Table 5-3 on page 34 are all based on 365 

days/year, but use the data from Tables 3-

10 and 3-11 that are based on 250 

days/year. Therefore, the values in Table 

3-15, Table 5-2, and Table 5-3 are too 

small by a factor of 365/250 = 1.46, and 

need to be revised upward in value by a 

factor of 1.46 to be correct.

NIOSH has reviewed the calculations. The intake rates in Tables 3-15 and 5-2 

are normalized to a calendar day intake rate based on an air concentration of 

578.38 dpm/m3

.

578.38 dpm/m3 x pCi/2.22 dpm x 1.2 m3/hr x 2000 hr/yr x 1yr/365 d 

= 1.71 x 103 pCi/d

Likewise, Table 5-3 is also a calendar day intake basis. So it appears that no 

adjustment is needed in the current TBD. However, in the next TBD 

revision, NIOSH will add footnotes to the tables to indicate that the values 

are normalized to calendar day rates.

Seconda

ry 

Finding 

B

3 AEC material buried and removed from 

ponds and grounds not documented or 

accounted for. 

SC&A has not found sufficient

documentation of the materials that were 

buried and then removed from the ponds, 

burial grounds, and trenches to allow for 

the determination of the potential exposure 

to workers, especially the ability to 

separate the AEC legacy weapons/ 

research-related materials from the other 

materials. Although it is stated on page 31 

of the TBD that, “The contents and 

locations of most disposal pits are well 

documented,” there are no references 

provided.

Workers involved with the remediation of the ponds/burial grounds were 

assumed to have been on a bioassay program and monitored 

accordingly. Therefore, in those cases we would assess the bioassay data and 

assign dose accordingly. The residual intakes would only be used to limit 

bioassay for non- remediation workers.

Additional data capture efforts are needed to determine if bioassay for all 

radionuclides was performed, or if only primary radionuclide (uranium) was 

monitored for and if we should be associating radionuclides to that. In 

general, the contents of the AEC material buried and removed from the ponds 

and grounds requires further evaluation.
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Seconda

ry 

Finding 

C

Burial Grounds workers and definition 

issue. 

Because many workers changed job 

locations/duties frequently (an “operator” 

at WRG could be doing anything from 

mixing chemicals, pressing pellets, digging 

a ditch, or operating a bulldozer), it would 

be difficult for the dose reconstructor to 

determine if a specific worker was 

involved in burial grounds activities. Also, 

it is not clear if the term Burial Grounds 

includes the trenches and ponds, where a 

large of amount of the cleanup took place 

in the residual period, or just the North 

Burial site, as indicated in Figure 2-2 of 

the TBD.

It is agreed that the definition of “Burial Grounds Workers” should be 

provided in the next TBD revision. 

Seconda

ry 

Finding 

D

Methods used to derive Table 5-5 not 

provided. 

External annual exposure rates for the 

residual period (1971–present) are provided 

on page 36 of the TBD. Presumably, the data 

in this table were derived from the maximum 

DWE of 578 dpm/m

3 

coupled with the 

average depletion rate of 0.00067/day from 

Table 5-1. However, it is not stated how the 

values in Table 5-5 were calculated; i.e., 

what resuspension rate was used, how the 

penetrating versus non-penetrating doses 

were derived, or whether rather this residual 

contamination is on the floor, work surfaces, 

ground, etc., and if this includes components 

of RU.

Further information on the methods used to derive the Table 5-5 TBD values 

should be documented in the next TBD revision to explain what we did.