Discussion of Metals and Controls 

Remaining Issues

Brant Ulsh, Ph.D., CHP

NIOSH, Research Health Physicist

Advisory Board on Radiation and Worker Health

Metals and Controls Work Group Meeting

December 6, 2023

National Institute for Occupational Safety and Health
Overview (1 of 2)

 Introduction

 Specific Issues

– Green lube (coagulant)

– Interior pipe contamination

– Confined spaces

– Dust loading

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Overview (2 of 2)

 Specific Issues (continued)

– Intrusive activity

– Data applicability

– Extreme conservatism

– Conservatism of 95th percentile soil contamination value

 Conclusions

12/06/2023 3
Introduction 
Introduction – Developments Since Last WG Meeting 

(1 of 2)

 Josie Beach presented, “Update: M&C Work Group Review of SECRelated Issues” at the ABRWH Meeting on 2023-08-16.

 NIOSH issued their latest response, “NIOSH Response to “SC&A 

Review [April 2023] of NIOSH Response [January 2023] to SC&A’s 

Supplemental Review of M&C Work Group Issues [August 2022]” on 

2023-08-22.

 SC&A issued their latest response, “SC&A Review of Overall NIOSH 

Response to SC&A’s Supplemental Review of M&C Work Group 

Issues as of November 2023, Revision 0 PC-1” on 2023-11-22.

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Introduction – What Has Changed? (2 of 2)

 Much of this presentation will look familiar, because not much has

changed since our last presentation on 2023-07-13:

– No new evidence on green lube;

– No new evidence on interior pipe contamination;

– No new evidence on confined spaces;

– No new evidence on intrusive activity;

– No new evidence on data applicability;

– No new evidence on extreme conservatism;

– No new evidence on 95th percentile soil contamination –

conservative.

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Specific Issues
Green Lube (1 of 4)

 SC&A has conflated the “green lube” (term used by 

interviewee) with “coagulant” (term used by both NIOSH and 

SC&A) with chemicals used in water treatment.

 This is a residual period. Uranium/Thorium (U/Th) is in soil and 

adhered to pipes - not waterborne, not subject to coagulation. 

 No evidence has been presented that green lube is corrosive 

or abrasive enough to displace U/Th from pipe scale/residue.

– Undesirable qualities in a lubricant.

12/06/2023 8
Green Lube (2 of 4

)

 Many materials can clog a drain line (e.g. bacon grease, coffee grounds, 

vegetable oil, toilet paper, etc.)

 Just because a material can clog a 

drain, that doesn’t make it 

functionally similar to coagulants 

used in water treatment, and no 

evidence supporting such a similarity 

has been produced.

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Green Lube (3 of 4)

 Even if green lube displaced U/Th (for which no evidence has 

been produced), it would be into the larger wet mass of lube, 

lowering the concentration, not concentrating it (a fraction of 

U/Th displaced from pipes divided by large mass of green 

lube). No evidence of concentration has been presented.

 Even if U/Th became entrained in green lube (for which no 

evidence has been produced), it would have been nonrespirable, lowering the exposure potential.

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Green Lube (4 of 4)

 The references SC&A cited regarding the use of coagulants in 

water treatment covered: 

– Removal of pharmaceuticals from wastewater;

– Use of aluminum or iron salts – not lubricants;

– Use of plant-based coagulants.

 While specific plant-based coagulants exist, none of the cited 

references demonstrate that commonly used lubricants 

generally, let alone green lube specifically, are functionally 

similar to water treatment coagulants. 

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Interior Drain Pipe Contamination (1 of 5)

 SC&A continues to assert, “a wide array of intrusive 

activities, many involving power tools, were used to 

cut, clean out, and repair these pipes, including saws, 

drills, grinders, powered snakes, and cutting torches. 

The specific tools employed would have depended 

upon the type of pipe (e.g., cast iron versus clay), the 

size and nature of the clog, and the size and condition 

of the pipe." (emphasis added) 

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Interior Drain Pipe Contamination (2 of 5)

 SC&A continues to assert, “While the Bridgeport Brass 

AWE hazard assessment focuses on the cutting of 

steel pipes, torch cutting was among several means by 

which cast iron (CI) pipes and vitreous clay (VC) pipes 

were cut at M&C by maintenance workers.”

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Interior Drain Pipe Contamination (3 of 5)

 As we previously stated, cutting torches (capable of generating 

fumes due to high temperatures) would not have been used on 

the clay or cast iron drain pipes. Torches are used on carbon 

steel pipes. No evidence was provided to support the routine 

use of torches on CI and VC pipes at M&C.

 Snap cutters, power snakes and saws would have been used, 

and the latter could generate respirable particulates.

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Interior Drain Pipe Contamination (4 of 5)

 There are 6 scale samples from inside pipes. 

 There 12 direct beta scintillator readings of scale from inside pipes. 

 There are additional interior pipe surface contamination samples. 

 There are 20 sediment/soil samples (surrounding pipes). 

 This set of data was NOT meant to be representative. It was meant 

to be biased high by focusing on the areas of highest contamination 

potential identified during the Pilot investigation. Intended to 

identify max, not range.

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Interior Drain Pipe Contamination (5 of 5)

 “The scope of the cited sampling of scale is very limited for

purposes of characterizing the range of activity levels within

M&C drain pipes and what may represent the upper bound of

that activity” (SC&A 2023, p. 19). (emphasis added)

 All sampling at every site is "limited;" M&C's sampling is more

comprehensive than what was previously accepted by the

Board for other sites.

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Confined Spaces

 “SC&A clearly acknowledges that this issue, by past practice and 

experience, is a TBD issue for which there are obviously means 

and information by which a more accurate dust loading factor 

can be derived." (SC&A 2023, p. 30)

 NIOSH agrees with the general need to review OTIB-70 and TBD6000 on the issue of confined spaces.

 NIOSH agrees that further discussion – if necessary – should be 

in the context of a TBD issue.

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Dust Loading (1 of 3)

 “SC&A stands by its original finding 2 (SC&A, 2022) that NIOSH’s

proposed application of Mound project data for deriving the

M&C dust loading factor does not satisfy the Board’s surrogate

data policy for site and process similarity given disparities

between the sites for confined space conditions” (SC&A 2023, p.

30).

 SC&A originally concurred with NIOSH.

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Dust Loading (2 of 3)

 “The renovation indoor dust loading of 10-4 g/m3 (100 μg/m3 ) 

might include excavation and would seem to independently 

support NIOSH’s use of 212 μg/m3 as a reasonable estimate 

when applied to the M&C subsurface indoor excavation 

scenario." (SC&A 2021, p. 18)

 “This range provides a prudently conservative estimate of actual 

radioactive dust-loadings in the workplace or household, and

serves as an adequate basis for the first-level generic screening 

analysis." (SC&A 2021, p. 18–19)

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Dust Loading (3 of 3)

 “...SC&A suggests that NIOSH also refer to NUREG/CR-5512 (in

addition to the Mound outdoor data) as a basis for the selected 

dust loading for both M&C and for use in OTIB-0070." (SC&A 

2021, p. 19)

 NIOSH concurred in our 8/23 response paper. We stand by our 

concurrence.

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Intrusive Activity

 We propose to use survey data from 1996 throughout the 

residual period (1968-1997). Similar to:

– Chapman Valve (soil data from 1987, and 1992 applied 

back to 1949)

• Diverse, intrusive work, similar to the situation at M&C

• Linde (data from 2001 applied to 1970-2006)

• Subsurface maintenance utility work, confined spaces

– Vitro (air data from 1977 applied to 1965 – 1985)

12/06/2023 21
Data Applicability (1 of 2)

 SC&A asserted, “A judgment on the question of 

whether there is sufficient similarity of conditions 

and processes between the D&D era, during which 

the 1995 characterization sampling was conducted, 

and the preceding M&C residual period maintenance 

activities resides with the Board, as it did for Linde 

Ceramics on a similar question between Linde’s D&D 

and renovation periods." (emphasis added)

12/06/2023 22
Data Applicability (2 of 2)

 The 1995 survey was not part of the D&D era. It was part of 

the maintenance period, prior to D&D.

 Weston stated that the purpose of the survey was, “The 

drainage system investigation was performed...in support of 

Nuclear Regulatory Commission (NRC) license termination and 

to assess the potential for inadvertent exposures to nonradiological workers performing routine drainage system 

maintenance...." (Weston, 1996, p. 2)(emphasis added)

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Extreme Conservatism (1 of 8)

 NIOSH has specified what it meant by extreme conservatism –

“conservative assumptions appropriate for a bounding scenario."

 SC&A’s inaccurate representation of NIOSH’s use of this phrase are 

based on its unsubstantiated assertions regarding confined spaces, 

green lube, and the applicability of sampling data from late in the 

maintenance period to the preceding years – a practice consistent 

with 20 years of program precedent. 

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Extreme Conservatism (2 of 8)

 SC&A selectively quoted former Board Member Melius, “carried to 

an extreme, we could take any site . . . and we could come up with 

what we think is the highest possible exposure at that site that 

would occur, and that would be bounding, and apply that to 

everybody that ever worked at the site” (ABRWH, 2011, p. 129). 

However, the essential questions, as the former Board Chair put it, 

are “is that a plausible bound? And then, who are we trying to 

characterize?” (ABRWH, 2011, p. 129). 

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Extreme Conservatism (3 of 8)

 SC&A did not quote Board Member Lockey, “It would be very 

difficult to say that for a guard, for instance, we are being 

unreasonable in setting a high exposure level for that guard 

because we don't have exposure records, but we do have for 

electricians or for a concrete worker." (ABRWH, 2011, p. 131). 

(emphasis added)

12/06/2023 26
Extreme Conservatism (4 of 8)

 SC&A did not quote Board Member Munn, “We do not have a 

situation where there is a long, unexplained period of potential 

extremely high exposure. We have a relatively short period of 

activity that takes place after decontamination, where the 

probability of extremely high doses is extremely low. The bounding 

dose that has been established is not likely to have been exceeded 

if it were at all, certainly not for any period of time." (ABRWH, 

2011, p. 133). (emphasis added)

12/06/2023 27
Extreme Conservatism (5 of 8)

 Board Member Munn continued, “If we are going to take a 

position that it is impossible for us to make bounding 

calculations as a reasonable argument, then we ought to be very 

straightforward about that and say we are not going to allow 

that, even though it has been specifically prescribed, as I 

understand it, by the legislation, that that is okay." (ABRWH, 

2011, p. 133). (emphasis added)

12/06/2023 28
Extreme Conservatism (6 of 8)

 SC&A did not quote Board Member Melius just one page later, “So, 

we have a lot of uncertainty, and the uncertainty leads to a 

bounding level that is quite high in order to be bounding, to try to 

take into account what is happening at the site." (ABRWH, 2011, p. 

130). (emphasis added)

12/06/2023 29
Extreme Conservatism (7 of 8)

 More Melius: “...during a residual period there may be different 

activities, but it is unlikely to lead to as high exposures or 

unusually high exposures. And so, the OTIB-70 approach is 

probably something that is appropriate and something I am 

personally comfortable with in these situations." (ABRWH, 2011, 

p. 146). (emphasis added)

12/06/2023 30
Extreme Conservatism (8 of 8)

 Clearly, the Board questioned whether high bounding doses were 

sufficiently accurate. 

 71 mrem is very low and comparable to natural background. 

Sufficient accuracy is not an issue at this low dose.

 Board previously accepted 100 mrem bounding dose at Sandia.

 In fact, doses <100 mrem are below NRC and DOE’s threshold for 

required monitoring! How can this be high enough to present 

sufficient accuracy concerns?

12/06/2023 31
Conservatism of 95th Percentile 

Soil Contamination Value

 Based on worker interviews and discussions with SC&A and the 

Work Group, NIOSH determined that exposure to contaminated 

soil near the Priority 1 drain pipes represented a bounding 

scenario.

 The highest soil concentration was found near a U fuel pin in a 

drain pipe. It is both bounding and plausible, as it is based on an 

observed condition.

12/06/2023 32
Soil Scenario is Bounding

 Other scenarios were developed in response to SC&A and WG 

concerns to show that they could be bounded to satisfy SC&A 

and WG concerns.

– NIOSH maintains that the soil scenario is bounding.

12/06/2023 33
Conclusion
Conclusion (1 of 3)

 Green lube (coagulant) – no evidence of concentration 

mechanism, and implausible.

 Interior pipe contamination/scale – data requested by SC&A and 

WG, and NIOSH provided it. Soil scenario is bounding.

 Confined spaces – not an issue at M&C for work with 

contaminated soils. TBD - not SEC- issue.

 Dust loading – agrees with (SC&A 2021) and NUREG/CR-5512. TBD 

- not SEC - issue.

 Intrusive activity – consistent with Chapman Valve, Vitro, and 

Linde, all accepted by the Board.

12/06/2023 35
Conclusion (2 of 3)

 Data applicability – 1995 survey is from the end of the 

maintenance period and was intended to assess maintenance, 

non-radiological worker doses. Directly relevant.

 Extreme conservatism – consistent with 20 years of program 

precedent. Low bounding dose (below required monitoring 

threshold), so not a sufficient accuracy issue.

 Conservatism of 95th percentile soil contamination value – data 

includes hot spots, biased high. Also includes contributions from 

noncovered contaminants.

12/06/2023 36
Conclusion (3 of 3)

 What is the concern?

– Bounding dose is too high to be sufficiently accurate?

– OR is it not high enough to be bounding? 

 We have addressed every issue raised by SC&A and the WG.

 Our positions today are the same as they were in 7/23, and even 

earlier. We can bound the dose with sufficient accuracy.

 No new evidence has been presented to change our conclusions, 

only unsupported speculation.

12/06/2023 37
For more information, contact CDC

1-800-CDC-INFO (232-4636)

TTY: 1-888-232-6348 www.cdc.gov

The findings and conclusions in this report are those of the authors and do not necessarily represent the 

official position of the Centers for Disease Control and Prevention.