SC&A’s Review of 

ORAUT-TKBS-0060, 

revision 00, “Grand 

Junction Facilities”

Ron Buchanan, PhD, CHP

Advisory Board on Radiation and Worker 

Heath, Subcommittee for Procedure Reviews

November 3, 2021
Introduction

◆ The Grand Junction Facilities (GJF) were located in 

Grand Junction, CO; covered period 1943–2006

◆ The site was under contract to the U.S. Atomic Energy 

Commission to support uranium processing, assaying, 

and milling remediation

◆ Some limited thorium exposures

◆ 1986 – Start of GJF remedial action project

◆ 2006 – GJF site released

◆ Special Exposure Cohort (SEC) 1943 through 1985 due 

to lack of internal dose reconstructability

2
Grand Junction Facilities dose 

reconstruction

◆ Before technical basis document (TBD) issued, NIOSH 

used a dose reconstruction (DR) template, “Dose 

Reconstruction Methodology for the Grand Junction 

Facilities,” September 15, 2015 (NIOSH, 2015a)

◆ ORAUT-TKBS-0060, revision 00, “Site Profile for Grand 

Junction Facilities,” issued on May 18, 2018 (NIOSH, 

2018)

◆ Subcommittee for Procedure Reviews tasked SC&A with 

reviewing the TBD at the February 18, 2021, meeting

3
Other GJF documents

◆ DCAS-PER-047, issued in 2014 (NIOSH, 2014)

◆ SCA’s 2015 review of PER-047 (SC&A, 2015)

◆ NIOSH’s 2015 addendum to the petition evaluation report for SEC 

Petition SEC-00175 (NIOSH, 2015b)

◆ SCA’s review of NIOSH’s addendum to Petition SEC-00175 (SC&A, 

2016)

◆ NIOSH issued DCAS-PER-090 (NIOSH, 2019) on July 17, 2019, to 

address DR methods modified by issuing the GJF TBD to replace the 

previous DR template for GJF

– SC&A has not been tasked to review PER-090

4
ORAUT-TKBS-0060 outline

◆ Section 1.0 – Introduction

◆ Section 2.0 – Site Description

◆ Section 3.0 – Occupational Medical Dose

◆ Section 4.0 – Occupational Onsite Ambient and 

Environmental Dose

◆ Section 5.0 – Occupational Internal Dose

◆ Section 6.0 – Occupational External Dose

5
SC&A’s review of section 2.0 site 

description

◆ Section 2.0 contains a reasonable amount of information 

about GJF that provides a useful background for the dose 

reconstructor 

◆ Table 2-1 summarizes the buildings and their usage 

periods

◆ SC&A had no findings or observations in this section

6
SC&A’s review of section 3.0 

occupational medical dose

◆ 1943–1946: Preemployment, annual, and postemployment

◆ 1947–1961: Taken off site, no occupational medical dose to be 

assigned

◆ 1962–1969: Preemployment, annual, and postemployment

◆ 1970–present: Taken off site, no occupational medical dose to 

be assigned

◆ SC&A found that the recommended occupational medical x-ray 

methodology was consistent with other DOE sites 

◆ SC&A had no findings but did have one observation

7
Observation 1

Observation 1: The term “each year” needs to be 

replaced

The recommendations for 1943–1946 contain the term 

“each year.” This could be misleading, because all the 

x-ray exams would not be assigned for each and every 

year. This observation was also identified in SC&A’s 

(2015) review of DCAS-PER-047 as observation 2 

(p. 16) but does not appear to have been corrected in 

the recent TBD.

8
SC&A’s review of section 4.0 

occupational onsite ambient and 

environmental dose

◆ Section 4.0 recommends that no onsite ambient and 

environmental dose be assigned because it is accounted 

for in any co-exposure data assigned to unmonitored 

workers, and there is no indication that ambient doses 

were subtracted from the monitored doses

◆ SC&A concurs with this recommendation and had no 

findings or observations in this section

9
SC&A’s review of section 5.0 

occupational internal dose

◆ SC&A verified the prorated intake values for the 

Supervisor and Administrative personnel in the intake 

tables 

◆ SC&A verified the ingestion intake values in the tables 

based on OCAS-TIB-009, revision 0 (NIOSH, 2004, p. 4)

◆ SC&A concurs with the recommendations in this section 

and has no findings 

◆ SC&A did have two observations

10
Observation 2

Observation 2: Apparent inconsistency in DAC 

values

In section 5.3.4 of the TBD, NIOSH used a Th-230 

derived air concentration (DAC) value of 3.00×10-12

microcurie per milliliter (μCi/ml) to derive intake values 

for table 5-6 for co-exposure intakes after 1990. 

However, NIOSH’s (2017) memorandum indicated that 

a DAC value of 7×10-12 μCi/ml was being used at the 

site. There appears to be an inconsistency in the DAC 

values used that needs clarification.

11
Observation 3

Observation 3: Potential radon calibration chamber 

exposure

◆ The TBD states (p. 20):

Any exposure from radon while working around the radon calibration 

chamber were calculated as WLM and should be provided in a workers 

exposure file.

◆ Did NIOSH examine the claimant files and find that workers who 

entered the chamber had such working level month (WLM) dose 

records in some claim files? 

◆ The radon calibration chamber could be a source term that may not 

be appropriately bounded by the 5.7 pCi/L found in Building 30B

12
SC&A’s review of section 6.0 

occupational external dose

◆ According to the GJF SEC, unmonitored external dose cannot be 

reconstructed prior to 1960. Therefore, this section is applicable to the 

period 1960 forward.

◆ SC&A reviewed the references in the TBD for the limit of detection (LOD) 

values and exchange frequencies and found them to be correct.

◆ Assignment of 100 percent 30–250 keV photons, 100 percent >15 keV 

betas, and 0.1–2 MeV neutrons is consistent with the potential radiation 

exposures at GJF (mainly uranium and decay products).

◆ SC&A analyzed the co-exposure methods for photons, betas, and 

neutrons presented in the TBD.

◆ SC&A has no findings concerning co-exposure photon dose data or their 

application.

13
SC&A’s review of section 6.5.2 

occupational external dose – betas

◆ The TBD (p. 27) recommends the use of a beta-to-photon 

dose ratio of 1.5 derived from the Radiation Exposure 

Monitoring System (REMS) database

◆ SC&A (2015, p. 14) reviewed the REMS data and 

concurred with using the beta-to-photon dose ratio of 1.5

◆ Since NIOSH recommends using the same ratio value of 

1.5 in the TBD, SC&A has no finding concerning 

co-exposure beta dose or its application

14
SC&A’s review of section 6.5.3 

occupational external dose – neutrons

◆ SC&A spot checked the missed dose data using the 

appropriate LOD and exchange values as summarized in 

table 6-3 of the TBD

◆ SC&A derived the same total neutron co-exposure doses 

as recommended in column 5 of table 6-5 in the TBD

◆ SC&A has no findings concerning co-exposure neutron 

dose data but did have two observations concerning 

assigning co-exposure neutron doses

15
Observation 4

Observation 4: Assigning 95th percentile 

neutron doses to geologist only

Workers with job titles other than geologist may have 

handled sources of neutrons in performing work and could 

have been in the 95th percentile exposure category. 

Geologists themselves may not have handled the tools as 

much as laborers and other workers.

16
Observation 5

Observation 5: Need substantiation for not 

assigning co-exposure neutron dose after 1985

The TBD states (p. 28):

After 1985, based on a review of GJF records, neutron 

dosimetry records are assumed to be complete. Therefore, 

no unmonitored dose should be assigned after 1985.

SC&A could not locate information in the TBD that supports this 

assumption. A summary of NIOSH’s review of the GJF records 

and the resulting assumption that monitoring for neutron exposure 

was complete would be appropriate to include in the TBD.

17
Summary

◆ SC&A reviewed the GJF TBD and compared the present TBD 

with the previous GJF DR template and previous SC&A 

reviews 

◆ SC&A found the TBD to provide reasonable and technically 

based recommendations, which were consistent with other 

DOE site profiles and the previous GJF DR template 

◆ SC&A had no findings in this review but did have five 

observations concerning:

1. the wording of text in the occupational medical section

2. DAC values used

3. radon calibration chamber exposure

4. neutron 95th percentile dose assignments

5. support of neutron dose recommendations in the external dose section

18
Questions?

19
References

National Institute for Occupational Safety and Health. (2004). Estimation 

of ingestion intakes (OCAS-TIB-009, rev. 0). 

https://www.cdc.gov/niosh/ocas/pdfs/tibs/oc-t9-ro.pdf

National Institute for Occupational Safety and Health. (2014). Grand 

Junction Operations Office (DCAS-PER-047, rev. 0). 

https://www.cdc.gov/niosh/ocas/pdfs/pers/dc-per47-r0.pdf

National Institute for Occupational Safety and Health. (2015a). Dose 

reconstruction methodology for the Grand Junction Facilities.

National Institute for Occupational Safety and Health. (2015b). SEC 

petition evaluation report Petition SEC-00175, addendum. 

https://www.cdc.gov/niosh/ocas/pdfs/sec/gjoo/gjfer-175add.pdf

20
References 2

National Institute for Occupational Safety and Health. (2017, July 27). 

Grand Junction monitoring program in 1991 [Memorandum]. 

https://www.cdc.gov/niosh/ocas/pdfs/dps/dc-gjoosec175r0-072717.pdf

National Institute for Occupational Safety and Health. (2018). Site profile 

for Grand Junction Facilities (ORAUT-TKBS-0060, rev. 00). 

https://www.cdc.gov/niosh/ocas/pdfs/tbd/gjf-r0-508.pdf

National Institute for Occupational Safety and Health. (2019). Grand 

Junction Operations Office (DCAS-PER-090). 

https://www.cdc.gov/niosh/ocas/pdfs/pers/dc-per90-r0-508.pdf

21
References 3

SC&A, Inc. (2015). A review of NIOSH’s program evaluation report 

DCAS-PER-047, “Grand Junction Operations Office” (SCA-TR-PR2015-

0093, rev. 1). https://www.cdc.gov/niosh/ocas/pdfs/abrwh/scarpts/scaper47-r1.pdf

SC&A, Inc. (2016). A focused review of the NIOSH SEC evaluation 

report for Grand Junction Operations Office, addendum to Petition SEC00175 (SCA-TR-2016-SEC006, rev. 0). 

https://www.cdc.gov/niosh/ocas/pdfs/abrwh/scarpts/sca-gjfsec66-r0.pdf

22