PANTEX SEC PETITION REVIEW

Summary of Progress

Presented by Brad Clawson

Chair, Pantex Work Group 

Advisory Board on Radiation and Worker Health

Pasco, Washington

August 23-25, 2011
Work Group Review: Overview

• Nov 20, 2007: Petition qualified

– “All employees who worked in all facilities at the Pantex Plant in Amarillo, TX, 

from Jan 1, 1951 through Dec 31, 1991”

• Aug 8, 2008: NIOSH Evaluation Report issued

– “NIOSH found no part of the class under evaluation for which it cannot 

estimate radiation doses with sufficient accuracy.”

• May 4, 2010; May 3, 2011: Work Group meetings

• Oct 26-28, 2010: Onsite tour

• 2009-2011: multiple onsite data captures, worker interviews
Work Group SEC issues

1. Adequacy of Internal Dose Records -- open 

2. Internal Dose Models for Uranium – open

3. Dose estimate approach for Plutonium – closed*

4. Dose estimate approach for Thorium – open

5. Internal Dose approach for Metal Tritides – closed*

6. Interpretation of External Dosimetry Data – closed*

7. 95th percentile neutron-to-photon ratio not bounding – open

8. Completeness of historical rad exposure sources – open

9. Incidents cited limited, incomplete – open

(* recommended by SC&A)
Work Group SEC issues (cont’d)

10. Inadequate consideration given to firing sites – open

11. Validation whether most highly exposed worker badged (external) – closed*

12. Accuracy of plant exposure data (petitioner issue) – closed*

13. Too few workers monitored for valid DR (petitioner issue) – open

14. Records incomplete for subcontractors, temp workers, short-term employees 

(petitioner issue) – closed*

15. Exposure from tritium leaks (petitioner issue) – open

16. Badge placement (petitioner issue) – open

17. Efficacy of HP and IH programs (petitioner issue) – closed,* merged with other 

issues 

(*recommended by SC&A)
Open Issue: Internal Dose Models for Uranium

• W28 involved uncased DU component whose corrosion resulted in contamination 

upon disassembly; first W28 disassembly in 1958.

• NIOSH ER stipulates 305 bioassay results from 1990 depleted uranium 

contamination “incident” with W28 system be used to bound all prior DU potential 

exposures; SC&A disagrees that 1989 incident is necessarily the worst (no 

objective basis in ER).

• ER indicates that 1990 results were used because “most comprehensive set of 

[DU] intake data found...” and represent “large, known high quality, intakes form 

exposures expected to be above normal operational exposures.”

• SC&A acknowledges that W28 system appears to have had highest exposure 

potential, but finds that at least one lab comparison shows mean uranium intakes 

for earlier years (1966-1979) to be double that of later years (1980-1990). 
Uranium (cont’d)

• NIOSH indicates that modeling of airborne contamination levels and analysis of 

available air sampling data tend to be in agreement with ER recommended intake 

values.

• However, SC&A believes use of pre-1990 workplace contamination and air 

sampling data to be of suspect reliability given 1989 DOE audit of Pantex internal 

dosimetry program finding gross inadequacies. 

• Recollections of the magnitude of the 1989 incident, as compared with prior 

contamination incidents, varies among interviewees.

• SC&A also questions retrospective use of 1990 bioassay results over 30 years of 

Pantex disassembly operations without some evidence of normalized operations, 

radiological controls, and monitoring (e.g., multiple units handled in bays during 

early years).
Uranium (cont’d)

• Worker categories potentially exposed to DU contamination from W28 

disassembly included technicians, supervisors, engineers, safety 

personnel, handlers, and other support personnel (all had access to W28 

bay areas).

• Contamination spread may have involved adjacent hallways, storage areas, 

and offices (contamination control inadequate, self-monitoring limited, 

RAMs used not BZ monitoring; beryllium contamination found in these 

areas).

• Interviews indicate that early workers entered and left bay areas without 

any routine egress monitoring.
Open issue: Thorium

• Thorium was contamination concern in at least four weapon systems 

dating back to 1960s.

• One bioassay performed in 1983, remainder in 1990s; results showed no 

intakes of significance.

• NIOSH proposes to base estimate of chronic intake of thorium on 2% of 

DU intake for times when thorium was present in disassemblies, based on 

observed mass ratios.

• Further review by work group awaits Board action on uranium SEC issue.
Other open SEC issues 

• Data adequacy and completeness – WG received NIOSH response to SC&A 

white paper on Aug 5, 2011; being reviewed.

• Too few workers monitored for valid DR (petitioner issue)

• Exposure from tritium leaks (petitioner issue)

• Inadequate consideration given to firing sites

• Badge placement (petitioner issue)
Summary

• Work Group recommends full Board review and action regarding dose 

reconstructability of worker exposure to depleted uranium at Pantex from 1958 

through 1983, where an exposure potential existed with the disassembly of the 

W28.

• Work Group deferring action for 1984 through 1991 pending further NIOSH 

assessment of whether 1989 bioassay data would be bounding for that specific 

“campaign” period and subsequent SC&A review of NIOSH approach.

• SC&A will continue its review of DU exposure potential during 1951-1958. 

• Work Group deferring action for thorium pending full Board review of uranium SEC 

issue.

• Remaining issues of data adequacy to be dispositioned with NIOSH and SC&A with 

receipt of NIOSH response of Aug 5, 2011.