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Metals and Controls SPECIAL EXPOSURE COHORT (SEC 236) ISSUES MATRIX

Effective Date: September 12, 2018 Draft 

NOTICE: This report has been reviewed to identify and redact any information that is protected by the Privacy Act 5 USC §552a

and has been cleared for distribution. 

F1 SEC Issue

Internal exposures associated with subsurface maintenance 

and repurposing activities in Building 10 during the 

residual period should be explicitly included in the ER. 

NIOSH should not assume that there is sufficient 

conservatism inherent in the internal dose reconstruction 

methods employed in the ER to account for these 

exposures.

F1 NIOSH Response

In October 2017, NIOSH (with SC&A’s participation) 

conducted interviews with personnel knowledgeable of 

subsurface activities during the residual period. Upon 

review of that data, NIOSH determined the current ER 

requires improvement to reflect exposure potential, and 

therefore created the subsurface exposure model white 

paper and will include the model in the revised ER.

F1 WG Notes: 

At the 5/3/18 meeting, the WG asked how NIOSH determined that the volumetric contamination data taken from the drain 

line characterization is representative of the exposures experienced by maintenance workers throughout the residual period; 

they asked if it could have been much higher. SC&A stated the use of a 95th percentile value from the sample data would 

accommodate the potential that there may have been higher contamination levels encountered that were missed by the 

characterization study. 

The following items were also discussed: the use of available sample data that was analyzed with either isotopic 

identification or gross alpha techniques, and the ability to model thorium exposures with the data. The amount of time 

subsurface work was performed each year as described by former workers was discussed. It was agreed that the use of a 

reference man heavy-breathing rate was a TBD issue. SC&A discussed their selected dust-loading value, and that it 

compared favorably with the value independently determined by NIOSH. 
Effective Date: September 12, 2018 Draft Page 2 of 25

Metals and Controls SPECIAL EXPOSURE COHORT (SEC 236) ISSUES MATRIX

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F1 SEC Issue 

(continued)

6/6/18: J. Beach email: 

1. NIOSH needs to demonstrate and back up their conclusions 

using example dose reconstructions applying assumptions 

and models being proposed with the information and data 

that is available.

2. NIOSH needs to confirm the adequacy and completeness of 

the data.

3. Work during M&C residual period; included renovations, 

demolition, and extensive maintenance all taking place 

without health physics support, training or knowledge of 

radiological hazards for the entire class period.

4. Radiological exposure potential in subsurface area drains, 

utility trenches and exterior areas during all previously 

mentioned activities have a high potential for residual 

radioactivity where workers were not monitored. The swipe 

samples NIOSH intends to use from late in the operation 

periods do not represent actual work that took place in the 

residual years.

5. No mention of maintenance work performed on the roof or 

potential exposure to workers is mentioned in the ER. As 

stated during worker interviews roof work could have taken 

2-3 months in a given year.

6. Unknown levels of Uranium and Thorium in subsurface 

areas inside and outside areas.

7. Combining and reducing all activities intrusive work, e.g., 

roof work, including rooftop, roof penetration work, roof 

line just under the roof deck, and drains, utility trenches, 

and exterior soil etc. to one month per year seems on the 

low side.

8. Please review and add petitioners concerns from [redacted] 

memo of May 28, 2018, as appropriate.

F1 NIOSH Response 

(continued)

1. As a standard practice, NIOSH documents example DRs and 

provides them to the Board after DR methods are determined 

and the ER is finalized.

2. This comment was discussed at the WG meeting and since 

then WG members have been provided with NIOSH’s 

Subsurface Exposure Model white paper. NIOSH 

considered the data available to characterize the subsurface 

environment and determined that the information used in this 

white paper was adequate for use with appropriate layers of 

conservatism applied. NIOSH will continue reviewing new 

information and working with SC&A to resolve any 

remaining data issues.

3. This statement is accurate for covered work but not for HFIR 

and D&D.

4. NIOSH determined the need for follow-up interviews after 

presenting the original ER to the Board. NIOSH then 

obtained additional information that was used to create a new 

model for bounding subsurface exposures that do not use

swipe samples from late in the operational period.

5. NIOSH will address roof penetration work in a new white 

paper.

6. NIOSH determined the 44 inside samples and 292 outside 

samples sufficiently characterized the subsurface work 

environment.

7. This issue is addressed by issue P4.

8. [redacted] concerns were added to this matrix as issues P1 

through P10.
Effective Date: September 12, 2018 Draft Page 3 of 25

Metals and Controls SPECIAL EXPOSURE COHORT (SEC 236) ISSUES MATRIX

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F1 Actions:

To Be Determined
Effective Date: September 12, 2018 Draft Page 4 of 25

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F2 SEC Issue

NIOSH incorrectly transcribed some of the Landauer filmbadge dosimetry reports and incorrectly calculated annual 

95th percentile external penetrating doses to workers in the 

residual period. 

F2 NIOSH Response

NIOSH agrees transcription errors were made and has 

recalculated doses as follows. Film badges at the end of 

AWE operations (i.e., 1967) were processed quarterly by 

Landauer (SRDB 13654 pp. 18-20, 97-133). NIOSH used 

all 374 of the “X” or “Gamma” exposure results from 1967 

to determine the quarterly geometric mean (GM) dose rate 

and geometric standard deviation (GSD). A quarterly GM 

gamma dose rate was determined to be 12 mrem/quarter 

(or 4 mrem/month) with a GSD of 2.61. Since the GSD is 

less than the Battelle-TBD-6000 default value of 5, a GSD 

of 5 will be assumed to be claimant favorable. Doses will 

be assessed assuming a claimant favorable gamma energy 

of 100% 30-250 keV. 

F2 WG Notes: 

At the 5/3/18 WG meeting, SC&A described their finding and were made aware of NIOSH’s response above. This Issue 

will be held in abeyance pending the outcome of Observation 5. 

5/15/18: R. Anigstein email - SC&A agrees with the solution to this issue that is proposed by NIOSH. 
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F2 SEC Issue 

(continued)

6/6/18: L. Valerio email: 

1. SRDB 13654 (Landauer External Dosimetry Reports) 

appear to list daily readings in excess of 12 mrem/quarter. 

Pages 69-70 list some employee readings of 100+ Gamma 

& x-ray doses for one day? (e.g.: Page 69, employee 

identification number 0528 shows 170 mrem on 10/1/1966). 

In addition, readings for 4/1/66 show ~ 15 employees with 

readings above 100 mrem. Is this the quarterly value?

2. Film badges issued to “SR” and “Temp” status workers 

show substantially higher “Permanent” readings. How do 

these represent the 12 mrem/quarter?

F2 NIOSH Response 

(continued)

1. Page 69 contains data from 1966 and was not used because 

AWE operations were still winding down and had not yet 

reached residual levels. NIOSH only used data from the last 

year of the AWE period, i.e., 1967.

2. NIOSH intends to develop an exposure model that is based 

on exposures that are representative of M&C personnel. The 

SR (Smidgen Room) badges were area monitors, and the 

“Temp” badges could have been assigned for a fraction of a 

quarter; therefore they were not used (See SRDB 13631 p. 

11).

F2 Actions:

To Be Determined
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Metals and Controls SPECIAL EXPOSURE COHORT (SEC 236) ISSUES MATRIX

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F3 SEC Issue

NIOSH incorrectly calculated annual 95th percentile beta 

skin-doses to workers in the residual period. 

F3 NIOSH Response

NIOSH has recalculated doses as follows. Film badges at 

the end of AWE operations (i.e., 1967) were processed 

quarterly by Landauer (SRDB 13654 pp. 18-20, 97-133). 

NIOSH used all 14 of the Type 2 or “Skin” exposure 

results from 1967 to determine the quarterly geometric 

mean (GM) dose rate and geometric standard deviation 

(GSD). A quarterly GM skin dose rate was determined to 

be 36 mrem/quarter (or 12 mrem/month) with a GSD of 

1.98. Since the GSD is less than the Battelle-TBD-6000 

default value of 5, a GSD of 5 will be assumed to be 

claimant favorable. Doses will be assessed assuming an 

electron energy of 100% >15 keV. 

F3 WG Notes: 

No Action to Date 
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Metals and Controls SPECIAL EXPOSURE COHORT (SEC 236) ISSUES MATRIX

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F3 SEC Issue

(continued)

5/15/18, R. Anigstein email:

1. SC&A has a different interpretation of the beta skin 

dose dosimetry data. We found only 12 quarterly badge 

reports with beta skin doses during 1967—badges that 

had a blank in the beta column were not counted. We 

found three numerical results—60, 90, and 140 

mrem—and nine results recorded as “M” (minimal). 

Since the LOD for beta doses was 40 mrem, according 

to Landauer, we assigned these badges a value of 

LOD/2 or 20 mrem. On that basis, we obtained a GM 

of 29.22 mrem per quarter, or 9.7 mrem/month, with a 

GSD of 2.03. 

2. A larger issue is that the Landauer badges only 

recorded betas with energies > 1.5 MeV; whereas betas 

with energies as small as 100 keV can contribute to 

skin dose. This issue needs to be explored further. 

F3 NIOSH Response 

(continued)

1. NIOSH reexamined the Landauer report and agree with 

the SC&A’s numerical results but found 11 “M” results.

2. The general note Landauer provides on their standard 

form indicates dosage due to betas less than 1.5 MeV 

may be recorded but not necessarily in millirems unless 

arrangements were made for calibration at other energy 

ranges (SRDB 13654 p. 16). However, on page 17 of 

SRDB 13631, Landauer says in a private letter to M&C, 

“The skin dose will be determined by measuring the 

density at the open window and comparing this with a 

calibration curve prepared in the same way from 

exposures to the natural uranium beta. The difference 

between this value for the open window and the gamma 

radiation value determined will be reported as the skin 

dose.” 

F3 Actions:

NIOSH and SC&A will exchange spreadsheets used to calculate the Beta dose and hold a technical call if necessary to 

resolve the disparity identified as item 1 in the 5/15/18, R. Anigstein email above. 
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Metals and Controls SPECIAL EXPOSURE COHORT (SEC 236) ISSUES MATRIX

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O1 SEC Issue

SC&A suggests that a more appropriate approach to 

deriving the chronic airborne concentration of uranium 

from resuspension during the residual period would be to 

use the average value for the swipe data (i.e., 12.3 dpm/100 

cm2) and a resuspension factor of 1E-5/m. This would 

result in chronic uranium inhalation rates that are about 2 

times higher, but well within a reasonable range for these 

types of exposures, given the available data. 

O1 NIOSH Response

NIOSH agrees that the use of average contamination levels 

is more appropriate, and will instead model the more 

aggressive airborne dust-producing activities with an 

enhanced resuspension factor. An updated approach will 

be in the revised ER.

O1 WG Notes: 

At the 5/3/18 meeting, the WG questioned the appropriateness of the survey locations included in the model, and the overall 

representativeness of the swipe data used in this model, given that much of the information was illegible. NIOSH described 

how these obstacles were overcome, and SC&A described their independent review of the data. The WG asked how well 

the model bounded exposures in the ceiling area near the rafters, or work performing roof penetrations, or HVAC 

maintenance. NIOSH indicated that these work scenarios would be included in the revised ER. The WG also expressed a 

concern regarding whether the equipment and machinery in building 10 had pockets of residual contamination or if they 

had been surveyed. NIOSH explained that equipment was shipped off-site at the end of operations and that the site 

documented surveys of equipment (e.g. SRDB 114235 pp. 45). 

O1 Actions:

NIOSH will create a white paper and include methods to bound exposures in the ceiling area, work performing roof 

penetrations, and HVAC maintenance. 
Effective Date: September 12, 2018 Draft Page 9 of 25

Metals and Controls SPECIAL EXPOSURE COHORT (SEC 236) ISSUES MATRIX

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O2 SEC Issue

The distinction between production and non-production 

workers should be better defined in the ER. After 

discussions with NIOSH, it was determined that the 

production worker group is intended to refer to workers 

who may have entered production areas. This includes 

construction trade workers, including but not limited to 

those listed in the ER. Additional text adding clarity to this 

point would ensure this distinction is consistently applied 

to workers. 

O2 NIOSH Response

NIOSH will revise the ER to clarify with language such as 

the following. All atomic weapons employees in the 

Facilities Construction and Maintenance Services 

Organization (Facilities) or Production Machine 

Operators/Helpers and Production Repair & Maintenance 

(R&M) organizations having access to, and work within 

Buildings 4, 5, and 10, or that performed subsurface work 

in the area surrounding Building 10, in the former Burial 

Area, the Metals Recovery Area, the Building 11 Stockade 

Area, the Building 11 Railroad Spur Area, and in the 

Building 12 West and South Lawn Areas, are considered to 

be production workers. The remaining atomic weapons 

employees having access to, and work within Buildings 4, 

5, and 10, are considered non-production or administrative 

employees.

O2 WG Notes: 

At the 5/3/18 meeting, the WG expressed a concern regarding the job titles of those that performed subsurface work outside 

of building 10. NIOSH explained that former workers indicated which job descriptions were called upon to perform this 

work and that it was the same group that was identified to perform the inside subsurface work and other maintenance 

activities such as HVAC maintenance and roof penetrations.
Effective Date: September 12, 2018 Draft Page 10 of 25

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O2 SEC Issue

(continued)

5/15/18, R. Anigstein email – SC&A disagrees with the 

distinction between construction, maintenance, and repair 

workers, and other workers who spent a major portion of 

their workdays in the residually contaminated areas. This is 

a TBD issue which does not affect the SEC. However, 

looking ahead, all workers whose doses will be 

reconstructed should be assigned radiation exposures of 

workers in the residually contaminated areas, unless it can 

be established that a large majority of their time was spent 

outside these areas, in which case they should be assigned 

to a separate job category. 

O2 NIOSH Response

(continued)

The description above includes both production and 

maintenance type workers (i.e. the primary occupants of 

the contaminated facilities); however, NIOSH agrees that 

all M&C workers that had access to Buildings 4, 5, and 10 

should be assigned radiation exposures commensurate with 

their occupancy rate. 

O2 Actions:

To Be Determined
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O3 SEC Issue

NIOSH should consider adopting the approach used in the 

ER for Carborundum and the ER and technical basis 

document for General Steel Industries (GSI) for deriving 

ingestion doses during the residual period. 

O3 NIOSH Response

When estimates of air concentration values are available, 

the OTIB-009 approach is the preferred approach. When 

air concentration data is not available, but surface or massbased contamination values are, NIOSH uses NUREG 

/CR-5512. The contamination data used for estimating 

ingestion rates are taken from the end of AWE operations 

and decayed over time consistent with the source-term 

depletion rate calculated with OTIB-70 methods.

O3 WG Notes: 

No Action to Date 
Effective Date: September 12, 2018 Draft Page 12 of 25

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O3 SEC Issue

(continued)

5/15/18, R. Anigstein email – OCAS-TIB-009 describes 

two pathways that contribute to the ingested intakes. One 

(Mode 2) is the deposition of the airborne activity on a 

beverage cup, the other (Mode 3) is the hand-to-mouth 

transfer from a contaminated surface. During the 

operational period, the two pathways make approximately 

equal contributions. Since the air concentration due to 

resuspension is much smaller than that during the AWE 

period, Mode 2 can be neglected during the residual period. 

Mode 3 assumes that 10% of the contamination on an area 

of 0.0155 m2 is ingested per day, which is equal to the 

contamination on an area of 0.00155 m2. This is double the 

ingestion rate of 10-4 m2/h cited in NUREG/CR-5512. 

Since the Mode 3 pathway is dependent only on the surface 

contamination level, it can be applied just as readily as 

NUREG/CR-5512. It is more claimant favorable and 

consistent with the ingestion intakes assigned in other 

circumstances.

O3 NIOSH Response

(continued)

TIB-9 is based on the concept that ingestion is proportional 

to contamination and contamination is proportional to 

airborne. We are aware that the NUREG hourly ingestion 

rate is approximately one-half of that used in TIB-009. In 

fact, this issue was addressed in a review by the 

Procedure’s Subcommittee. The discussion of this is 

documented in the Board Review System under 

Overarching Issue #2.

O3 Actions:

To Be Determined
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O4 SEC Issue

Exposures experienced by High Flux Isotope Reactor 

workers cannot be used “as supporting evidence to validate 

the bounding method used in Section 7 of this report”, as 

stated on page 24 of the ER. 

O4 NIOSH Response

NIOSH agrees that exposures to personnel working within 

the HFIR Fuel Manufacturing Area were likely much 

larger than exposures to covered personnel. NIOSH will 

delete or edit our comparison to the reference cited by 

SC&A (SRDB 24654 p. 34) to clarify the assessment. 

O4 WG Notes: 

At the 5/3/18 WG meeting, SC&A agreed with the NIOSH response. 

O4 Actions:

To Be Determined
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O5 SEC Issue

SC&A is concerned that it may be inappropriate to use 

external dosimetry data collected during the last year of 

Atomic Weapons Employer (AWE) operations as the basis 

for bounding the external doses during the residual period. 

Specifically, during the AWE operations period, large 

quantities of uranium and thorium were on site and handled 

by AWE workers to manufacture fuel elements and fuel 

assemblies. All of this fuel, which would have been 

responsible for the majority of external exposures to AWE 

workers, was removed from the site at the end of AWE 

operations and would not have been present during the 

residual period. 

O5 NIOSH Response

AWE fuel was removed at the end of AWE operations in 

1967; however, a sizable amount of HIFR fuel remained 

(SRDB 168315). Therefore, rad levels inside the HFIR 

area would have been higher than those outside of HFIR as 

concluded by SC&A in Observation 4 above. In addition, 

M&C was required by their H&S Manual to perform 

routine surveys and would have identified anomalous rad 

levels in accessible areas (SRDB 16985). The highest 

average dose to HFIR workers during a 5 1⁄4 year period 

was 48.3 mrem/quarter. This compares favorably with the 

doses NIOSH calculated for those outside HFIR area, i.e. 

12 mrem/quarter.

In its current approach, NIOSH does not deplete the source 

term for external doses during site residual period, making 

doses assigned in the ER more conservative than that 

described by this observation. However, NIOSH agrees 

that the source term over time should deplete for these 

exposures, and will provide new calculations in the revised 

ER to maintain an agreement with depletion of external 

doses. NIOSH doesn’t believe this as an SEC issue 

because there are other methods including Section 5.1.2 of 

Battelle TBD-6000 available to bound these doses. 
Effective Date: September 12, 2018 Draft Page 15 of 25

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O5 WG Notes: 

At the 5/3/18 WG meeting, SC&A stated that reliance on film badge data from the end of AWE operations (i.e. 1967) was 

inappropriate because the fuel that caused that film badge data was no longer on-site. NIOSH stated that the new method 

uses the geometric mean of the data as opposed to the 95th percentile and that 45% of the film badge results were reported 

as the minimum quantity measurable, making the use of this data appropriate. NIOSH also pointed out that NMMSS 

inventory data shows 694 kg of uranium present in 1966 and 172 kg in 1967 (a 4 fold decrease), which indicates the 1967 

data was obtained during a period after the AWE source-term was significantly reduced.

O5 Actions:

To Be Determined
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P1 SEC Issue

The data from the AWE-operational period was from 

controlled work areas where workers had received health 

physics training and engineering-administrative controls 

were in place to limit contamination to workers and the 

workplace. The class of employees who are the subject of 

this petition, M&C Facilities Construction & Services, and 

R&M (M&C maintenance) workers, did not enjoy any of 

these benefits. They were untrained, unmonitored and 

unaware of the significant quantities of AWE source 

materials that they were exposed to on a routine basis when 

working in subsurface soils, in drains, in utility trenches, 

on the roofs and in exterior areas where waste materials 

had been handled. Furthermore, the M&C maintenance 

workers came in direct contact with the source materials, 

using aggressive work practices with no 

engineering/administrative controls to limit exposure. 

There is simply no comparison between the two 

populations. 

P1 NIOSH Response

In the ER, NIOSH created a model to bound doses to the 

majority of M&C workers, i.e., those that performed 

production and support tasks. NIOSH has since obtained 

additional information and has developed another model to 

bound doses to those that performed more invasive tasks, 

as identified by the petitioner in our Subsurface Exposure 

Model white paper. 

P1 WG Notes: 

No Action to Date 

P1 Actions:

To Be Determined
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P2 SEC Issue

The 1982 decommissioning surveys, on which the NRC 

based its decisions to release the building interiors for 

unrestricted use, were substantially flawed. More 

importantly, they were limited in scope. They only covered 

accessible former AWE manufacturing areas (note: most of 

the former AWE manufacturing areas had already been repurposed by this time and were under heavy use 24-hours 

per day, so access was extremely limited). There were no 

intrusive surveys of subsurface areas, or inside the drains 

and utility trenches that served the former AWE areas, or 

any of the overhead areas, or any of the exterior areas 

where waste had been managed. And as evidenced by the 

comprehensive characterization surveys conducted in 1994 

and 1995, the 1982 surveys missed considerable amounts 

of residual activity even in the limited areas they did cover.

P2 NIOSH Response

NIOSH used the 1982 decommissioning surveys to 

develop part of the model in the ER used to bound doses to 

the majority of M&C workers and not to those that 

performed more invasive tasks as identified by the 

petitioner. NIOSH considers accessible contamination 

levels to be more appropriate for use in modeling 

exposures to the typical worker, as opposed to the 

contamination in inaccessible areas that was removed 

during D&D after 1994. 

P2 WG Notes: 

No Action to Date 

P2 Actions:

To Be Determined
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P3 SEC Issue

The 1992 characterization surveys were limited to the 

former burial site. In 1992, we were still ignorant of the 

other areas where residual radioactivity from AWEoperations had come to be located: the previously released 

building interior areas, subsurface soils, subsurface drains, 

utility trenches, roofs and the exterior areas where waste 

had been managed. The full extent of the residual 

contamination remained unknown until after the 

comprehensive characterization surveys were conducted in 

1994 and 1995. 

P3 NIOSH Response

The 1992 characterization surveys are only a small part of 

the data set NIOSH uses in the new subsurface model. 

NIOSH considered the data available to characterize the 

subsurface environment and other work environments. 

NIOSH determined that the information published in the 

Metals and Controls Corp. Subsurface Exposure Model 

white paper was adequate for use with appropriate layers of 

conservatism applied. Additionally, NIOSH used 

characterization data from 1982, 1992, and 1994-95 to 

develop the subsurface, internal, and external models. 

NIOSH will continue reviewing new information and to 

resolve any remaining data issues.

P3 WG Notes: 

No Action to Date 

P3 Actions:

To Be Determined
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P4 SEC Issue

I am skeptical of the estimate of the one-month duration of 

excavation activity over any given year. In addition, to 

open trench excavations (which seems to be the basis of the 

one month estimate), M&C maintenance workers would 

have been exposed to subsurface residual radioactive 

source materials, perhaps even more often, for tasks that 

required no excavation. This would have included snaking 

out plugged drains, pulling wires through underground 

conduit, installing and repairing services in subsurface 

utility trenches, etc.

P4 NIOSH Response

NIOSH and SC&A made a concerted effort to ask site 

experts about occupancy rates during worker interviews 

(SRDBs 170018 p. 6, 169916 p. 5, 169938 p. 8, 169924 p. 

7, and 169919 p. 5). NIOSH distilled that information to 

arrive at the 1-month occupancy rate. In SC&A’s ER 

review on page 8, they also arrived at a 1-month occupancy 

rate. NIOSH appreciates that maintenance rates would 

have varied from 1968 to 1997, and will reassess the 

interview transcripts to confirm if one month is an 

appropriate occupancy rate for combined maintenance 

work. 

P4 WG Notes: 

No Action to Date 

P4 Actions:

To Be Determined
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P5 SEC Issue

The 1995 Drainage System Characterization Report 

includes 15 grab samples of accumulated sediment or 

surrounding soils in discrete locations of the pipe where 

elevated direct measurements were observed. The grab 

sample analyses report an isotopic analysis of uranium, but 

no other radionuclides. In retrospect, we now know that 

thorium would have also been present, as it was historically 

processed on the same manufacturing equipment as 

uranium during the AWE program. But given the 

limitation of the 1995 survey measurements, we have no 

way of knowing how much thorium source term was 

present in the residual radioactivity to which the M&C 

maintenance workers were exposed.

P5 NIOSH Response

NIOSH is aware that a small amount of thorium work was 

done on the same equipment in the same areas as the 

uranium work. NIOSH is also aware that the equipment 

was cleaned or shipped offsite, and the areas cleaned (not 

D&D’d) when those Ops ceased prior to the start of the 

residual period. NIOSH relies on the available data and 

has modeled thorium exposures for those areas where we 

have thorium data. If the petitioner is aware of new 

information, NIOSH will consider it. 

P5 WG Notes: 

No Action to Date 

P5 Actions:

To Be Determined
Effective Date: September 12, 2018 Draft Page 21 of 25

Metals and Controls SPECIAL EXPOSURE COHORT (SEC 236) ISSUES MATRIX

NOTICE: This report has been reviewed to identify and redact any information that is protected by the Privacy Act 5 USC §552a

and has been cleared for distribution. 

P6 SEC Issue

NIOSH may argue that there were numerous gross-alpha 

measurements of contaminated subsurface soils 

documented under Building 10, but I would argue that is 

not the same as the drains. So while NIOSH may be able 

to conservatively assume the worst case for the gross alpha 

measurements and reconstruct the dose to the organ of 

concern that would result in the highest dose, whether that 

be for thorium or uranium, the same cannot be said of the 

subsurface drains, where we only have isotopic uranium 

analysis and some direct measurements of beta/gamma 

radiation. Therefore, we can never know for sure what the 

exposures were to M&C maintenance workers who were 

exposed to source materials in the drains.

P6 NIOSH Response

In the Subsurface Exposure Model white paper, NIOSH 

presented a new method to model exposures to source 

materials in the drains that assign both uranium and 

thorium exposures to M&C maintenance workers. 

P6 WG Notes: 

No Action to Date 

P6 Actions:

To Be Determined
Effective Date: September 12, 2018 Draft Page 22 of 25

Metals and Controls SPECIAL EXPOSURE COHORT (SEC 236) ISSUES MATRIX

NOTICE: This report has been reviewed to identify and redact any information that is protected by the Privacy Act 5 USC §552a

and has been cleared for distribution. 

P7 SEC Issue

SC&A’s review of subsurface exposures in outside areas 

relies heavily on the Sowell (1985) Radiological Survey, 

but this investigation was largely limited to surface surveys 

with only a dozen or so soil borings with samples collected 

at certain pre-determined depth intervals. Relying on the 

Sowell (1985) data to estimate the bounding dose of 

excavation activities is not representative of the likely 

exposures of M&C maintenance workers.

P7 NIOSH Response

The Sowell (1985) Radiological Survey is only a small part 

of the data set NIOSH uses in the new subsurface model. 

NIOSH considered the data available to characterize the 

subsurface environment and other work environments. 

NIOSH determined that the information published in the 

Metals and Controls Corp. Subsurface Exposure Model 

white paper was adequate for use with appropriate layers of 

conservatism applied. Additionally, NIOSH used 

characterization data from 1982, 1992, and 1994-95 to 

develop the subsurface, internal, and external models. 

NIOSH will continue reviewing new information and 

continue to resolve any remaining data issues.

P7 WG Notes: 

No Action to Date 

P7 Actions:

To Be Determined
Effective Date: September 12, 2018 Draft Page 23 of 25

Metals and Controls SPECIAL EXPOSURE COHORT (SEC 236) ISSUES MATRIX

NOTICE: This report has been reviewed to identify and redact any information that is protected by the Privacy Act 5 USC §552a

and has been cleared for distribution. 

P8 SEC Issue

Internal Exposures Associated with HVAC Maintenance. 

SC&A suggests a couple of alternative approaches to 

estimate the accumulated activity on HVAC air filters with 

no allowance for any residue from the former AWE 

operations, only what has been deposited during Year-1 

from airborne concentrations associated with resuspension 

of low levels of removable surface contamination inside 

the buildings. This does not resemble what the M&C 

maintenance workers have described as grime and debris 

accumulated during years of AWE operations involving 

metal finishing operations including melting, forging, 

extrusion, rolling, chemical milling, machining, welding, 

and assembly. 

P8 NIOSH Response

NIOSH agrees with the general approaches taken by 

SC&A to model exposures to HVAC workers, and the only 

contamination that can be used to model exposures is 

contamination that originated prior to the start of the 

residual period on 1/1/1968. 

NIOSH will create a white paper to include a description of 

HVAC work and will demonstrate how exposures to 

HVAC workers are bounded. 

P8 WG Notes: 

No Action to Date 

P8 Actions:

To Be Determined
Effective Date: September 12, 2018 Draft Page 24 of 25

Metals and Controls SPECIAL EXPOSURE COHORT (SEC 236) ISSUES MATRIX

NOTICE: This report has been reviewed to identify and redact any information that is protected by the Privacy Act 5 USC §552a

and has been cleared for distribution. 

P9 SEC Issue

For roof penetration activities, there should be no depletion 

of the source term. Each time a roof penetration was made, 

the Facilities Construction & Services maintenance worker 

would have been exposed to the full dose of whatever 

source material had accumulated in that particular location. 

Each roof penetration was a new location with an undepleted source term.

P9 NIOSH Response

NIOSH believes the petitioner is referring to this area’s 

inaccessible nature, and that it was not routinely cleaned. 

NIOSH has methods available to bound exposures to 

personnel that access these areas and will address these 

exposures in a separate white paper.

P9 WG Notes: 

No Action to Date 

P9 Actions:

To Be Determined
Effective Date: September 12, 2018 Draft Page 25 of 25

Metals and Controls SPECIAL EXPOSURE COHORT (SEC 236) ISSUES MATRIX

NOTICE: This report has been reviewed to identify and redact any information that is protected by the Privacy Act 5 USC §552a

and has been cleared for distribution. 

P10 SEC Issue

The 1982 decommissioning surveys were substantially 

flawed. More importantly, they were limited in scope. 

They only covered accessible former AWE manufacturing 

areas (Note: most of the former AWE manufacturing areas 

had already been re-purposed by this time and were under 

heavy use 24-hours per day, so access was extremely 

limited). There were no intrusive surveys of subsurface 

areas, or inside the drains and utility trenches that served 

the former AWE areas, or any of the overhead areas, or any 

of the exterior areas where waste had been managed.

P10 NIOSH Response

NIOSH created a new method to model subsurface 

exposures that do not rely upon the 1982 decommissioning 

surveys. 

P10 WG Notes: 

No Action to Date 

P10 Actions:

To Be Determined