NOTICE: This report has been reviewed to identify and redact any information that is protected by the 

Privacy Act 5 U.S.C. § 552a and has been cleared for distribution.

MEMORANDUM

TO: INL Work Group 

FROM: SC&A, Inc.

DATE: July 14, 2016 

SUBJECT: Progress Report: ANL-W SEC-00224 Review, Strategy of Using the 10% 

Maximum Permissible Concentration Rule for Performing Dose Reconstruction

NIOSH Evaluation Report Approach

As noted in the Special Exposure Cohort (SEC) 00224 evaluation report (ER) for Argonne 

National Laboratory-West (ANL-W), “with a few exceptions, the majority of the actinides at the 

EBR-II Complex were present with mixed fission products.” The principal exceptions noted were 

the Zero Power Plutonium Reactor (ZPPR) and the Fuel Cycle Facility (FCF). The potential for 

uranium exposures at ZPPR can be considered minimal because the fuel sources were coated and 

encapsulated, and a strong contamination control program was in place. However, at FCF, the 

ER is clear that “because of FCF Hot-Line start-up activities, FCF machine shop activities, and 

Cold-Line fuel production at the FCF, ITF, and FASB, more-than-incidental intakes of depleted 

and enriched uranium without fission products present could have occurred from August 1967 to 

as late as 1994.” Further, as noted in the ER, no uranium bioassay data has been found for 

ANL-W workers prior to July 1983 (after which there was a significant increase in uranium 

bioassays that can be used to estimate intakes). 

For its dose reconstruction approach, the National Institute for Occupational Safety and Health 

(NIOSH) concludes that “exposures to uranium without mixed fission products can be bound 

using 10% of MPC [maximum permissible air concentration] from available air monitoring 

data,” an approach referenced in ORAUT-OTIB-0018, Internal Dose Estimates for Facilities 

with Air Sampling Programs (hereafter referred to as “OTIB-0018”), ORAUT-OTIB-0033, 

Application of Internal Doses Based on Claimant-Favorable Assumptions for Processing as Best 

Estimates (hereafter referred to as “OTIB-0033”). These OTIBs provide a basis for assigning 

bounding doses assuming routine operating conditions where airborne exposures were strictly 

controlled to ensure airborne particulates did not exceed 10% of the MPC over the course of a 

worker’s employment. As emphasized during Advisory Board and SC&A reviews of these 

OTIBs,1

 this approach is sound if: 1) an adequate air sampling program was in place at the time 

that the worker of interest was employed at a given facility; 2) the worker can be assigned to a 

specific job category; 3) there is assurance that the air sampling data are representative of the 

breathing zone (notwithstanding the uncertainty assigned to the airborne concentrations); and 

4) appropriate consideration is given to possible exposures to tritium, carbon-14, radon, and 

noble gases, which are not covered. 

1 See SC&A’s Review of NIOSH/ORAUT Procedures and Methods Used for Dose Reconstruction (Supplement 1), 

August 3, 2007.

NIOSH similarly applies this dose reconstruction approach for thorium without mixed fission 

products (MFPs) present (FCF Hot-Line, as thoria crucible coatings, August 1963–November 

1967) and for plutonium without MFPs present (ZPPR).

 
Memo – ANL-W 10% MPC Strategy 2 SC&A – July 14, 2016 

NOTICE: This report has been reviewed to identify and redact any information that is protected by the 

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SC&A Review to Date

SC&A considers this ER approach (10% MPC) to be reasonable for ZPPR given the 

encapsulation of the fuel, but questionable for uranium and for thorium (without MFPs present) 

at FCF. SC&A has focused on the basis for applying OTIB-0018 and OTIB-0033 to these latter

potential exposures at FCF because: 

1. Historically, U.S. Department of Energy (DOE) reactor operations had more formality of 

operations, including contamination control, than did material production or processing 

operations – this is borne out in past reviews under the Energy Employees Occupational 

Illness Compensation Program Act. 

2. DOE Order 5480.11, governing occupational radiation protection requirements and 

instilling more uniform and robust health physics programs across DOE, was not issued 

until 1988. 

3. While the ANL-W site profile indicates that alpha emitters as a primary contaminant 

were limited on a facility basis to the Specific Manufacturing Capability facility, it is 

clear that for FCF there were specific operational campaigns that handled alpha-specific 

radionuclides (these included machining of uranium-235 [U-235] and depleted uranium, 

handling of thoria-coated crucibles, handling of plutonium fuel, etc.). 

The SC&A review strategy is principally based on two of the four criteria outlined above: 

• To review the relative “robustness” of the FCF health physics program, particularly the 

adequacy of the prevailing contamination control and air sampling programs at the time

• To evaluate the representativeness of what air sampling results existed during the time 

period in question to what would be representative of breathing zone for the workers 

involved in specific radiological operations

For the first review, SC&A searched and reviewed ANL-W references in the Site Research 

Database (SRDB) pertaining to the FCF health physics (HP) program as it pertained to alpha 

emitters as the primary contaminant, e.g., air sampling, respiratory protection, contamination 

control, intakes and uptakes, and smear and air sampling results. Attention was also focused on 

FCF operational experience during the time periods of interest regarding handling of pure alpha 

emitters.

SC&A found that FCF relied on respirators (half and full) to control against intakes of airborne 

particulates when performing work in the cells and on components withdrawn from the cells. No 

clear evidence has been found that respirators were routinely worn for other work (e.g., 

machining, decontamination work, maintenance) under the premise that HP surveillance and 

available ventilation would mitigate against undue potential exposure to airborne particulates. It 

is not clear that the first and third premise of OTIB-0018 were satisfied in these cases, i.e., 

that an adequate air sampling program was in place and that the air sampling data were

representative of the breathing zone. The location of FCF air samplers is key given the nature 
Memo – ANL-W 10% MPC Strategy 3 SC&A – July 14, 2016 

NOTICE: This report has been reviewed to identify and redact any information that is protected by the 

Privacy Act 5 U.S.C. § 552a and has been cleared for distribution.

of the work. Unlike Experimental Breeder Reactor I (EBR-I), machining and decontamination 

activities would have entailed close-in, hands-on procedures by workers, and general air 

sampling would not have likely captured these exposures. A review of this issue – general versus

breathing zone air sampling – is provided in SC&A’s Review of Petition Evaluation Report for 

SEC-00224, Argonne National Laboratory-West Regarding the Use of General Area Air 

Sampling for Internal Dose Assessment, issued July 13, 2016. That review concludes that, “given 

the high degree of uncertainty surrounding GA [general area] air sampling data at the FCF (and 

possibly other locations at ANL-W)...NIOSH’s proposed value of 10% MPC(40) as a bounding 

value for internal dose assessment lacks credibility.” 

In terms of contamination control, the monthly HP reports for FCF during 1968–1969 are replete 

with instances where contaminations were experienced when components were removed from 

the cells, when decontaminations were performed in plastic tents, when components were 

machined, and when respirators/anti-Cs were not worn properly. Even for actual high-potential 

exposure work in the cells, stringent respiratory protection requirements were not imposed until 

1967, on the heels of an intake incident. While judgments on the robustness of the HP 

program at FCF are obviously subjective, it is clear that FCF was at the lower end of the 

ANL-W spectrum, particularly compared to the reactors. 

Next Steps

SC&A will continue to investigate the following questions as the inquiry proceeds: 

• Are there any corroborating data or references that can be produced to support the 

assumption that general air concentrations at FCF (and ANL-W, at large) closely 

correspond to operational air concentrations to which workers would have been actually 

exposed?

• Otherwise, if non-representativeness of air sampling data precludes use of OTIB-0018 

and OTIB-0033 and coworker model development remains an option, how can that be 

accomplished if no breathing zone air sampling data, smear data, or bioassay data 

exist for a particular activity (e.g., machining of U-235, depleted uranium)? Is FCF the 

only facility for which this is an issue? Are there any source term characterization data 

for these activities?

• A review of the 1968–1969 monthly HP reports for FCF show incidental contaminations 

involving MFPs and alpha particulates occur frequently (just about every month) and 

were typically found by frisking of personnel or contamination surveys following jobs. 

How can these incidental exposures be addressed when follow-up smears, air 

sampling, and bioassays are usually lacking? 

• While the technical basis document (ORAUT-TKBS-0007-5) indicates that, “If personnel 

were required to work in an area or building where known air contamination was 

present, respirators were worn to reduce internal contamination intake to levels below 

detectable amounts,” it not clear for FCF that this was rigorously implemented, 
Memo – ANL-W 10% MPC Strategy 4 SC&A – July 14, 2016 

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particularly before 1967, as shown by the then-newly enacted control policies issued 

following a serious incident.2 Alpha contaminations without MFPs were routinely 

detected on personnel performing work in the FCF small decontamination room, FCF 

machine shop, FCF chemical analysis laboratory, and FCF Rooms 20 and 26, without 

respiratory protection being indicated (see SRDB Ref. IDs 59958 and 59959). If 

respirator use was not rigorously enforced for routine work at FCF involving 

potential intakes of airborne particulates (e.g., outside of cell work), how can these 

potential intakes be bounded when air sampling and smear data are not available?

2 See SRDB Ref. IDs 140297, 145077, 138885, and 138887. 

References

NIOSH 2016. SEC Petition Evaluation Report: Petition SEC-00224, National Institute for 

Occupational Safety and Health, Cincinnati, Ohio. February 18, 2016. 

ORAUT-OTIB-0018. Internal Dose Estimates for Facilities with Air Sampling Programs, 

Revision 01, Oak Ridge Associated Universities. August 9, 2005. 

ORAUT-OTIB-0033. Application of Internal Doses Based on Claimant-Favorable Assumptions 

for Processing as Best Estimates, Revision 00, Oak Ridge Associated Universities. April 20, 

2005. 

ORAUT-TKBS-0007-5. Idaho National Laboratory and Argonne National Laboratory – West – 

Occupational Internal Dose, Revision 03, Oak Ridge Associated Universities. March 2, 2010. 

SC&A 2007. Review of NIOSH/ORAUT Procedures and Methods Used for Dose Reconstruction 

(Supplement 1), SC&A, Inc., Vienna, Virginia. August 3, 2007. 

SC&A 2016. Review of Petition Evaluation Report for SEC-00224, Argonne National 

Laboratory-West Regarding the Use of General Area Air Sampling for Internal Dose 

Assessment, SC&A, Inc., Vienna, Virginia. July 13, 2016.