Los Alamos SEC Petition Review

Mark Griffon, Chair

LANL Work Group

Advisory Board on Radiation and Worker Health

Santa Fe, NM

June 18-21, 2012
Work Group Review: Overview

• May 29, 2008: SEC petition 00109 qualified

Service support workers who worked in any operational Technical 

Areas with a history of radioactive material use at the Los Alamos 

National Laboratory from January 1, 1976 through December 31, 

2005.

• January 22, 2009: NIOSH evaluation report (ER) issued

NIOSH found no part of the class under evaluation for which it 

cannot estimate radiation doses with sufficient accuracy.

• April 2010: SC&A review of evaluation report

• Work Group meetings (4): Apr and Nov 2010, May 2011, May 2012

• Various onsite visits, worker interviews, data capture
Other Los Alamos SEC petition evaluations 

• SEC-00061 (Aug 2006): All employees...associated with radioactive 

lanthanum (RaLa) operations...from September 1, 1944, through July 18, 

1963... SEC class designated 11/9/06.

• SEC-00051 (Feb 2007): All employees...working in operational Technical 

Areas with a history of radioactive material...from March 15, 1943 through 

December 31, 1975... SEC class designated 6/22/07.

• SEC-00170 (Apr 2010): All employees...who worked...from March 15, 1943 

through December 31, 1975. SEC class designated 7/13/10.

• SEC-00109 : All service workers ..who worked in any operational Technical 

Area with radioactive materials ..from January 1, 1976 to December 31, 

2005. Open / Active Petition.
Work Group SEC Issues

1. Capability to monitor and measure Mixed Activation and Mixed Fission 

Products by 1976 – Open

2. DR approach for exotic radionuclides -- Open

3. Completeness and reliability of in vitro and in vivo data, and adequacy of 

NIOSH coworker model – Open

4. DR approach for neutron exposures – Closed

5. DR approach for workers beside LAMPF/LANSCE retention pond/beam 

stop – Open (pending DR demonstration)

6. DR approach for Special Tritium Compounds -- Open

7. Issues related to unmonitored exposure of support service personnel –

Open (pending clarification)

8. Petitioner issues (firing sites, Cerro Grande fire, etc.) -- Open
Petitioner SEC issues

• Exotic radionuclide exposures at firing sites

• Badge access to radiological areas – Closed

• Occupational Health Reports reliance on worker “self-reporting”

• Issues related to occupational environmental model cited

• Doses received by support personnel responding to Cerro Grande fire

• Similarity between LANL and NTS operations re: “campaign-based” 

activities
SEC Issue 1: Capability to monitor and measure Mixed 

Activation (MAPs) and Mixed Fission Products (MFPs) by 1976

Description of Issue:

• Inability to dose reconstruct MAPs and MFPs figured prominently in SEC 

decision for 1943-1975. 

• NIOSH concludes that by 1976, in vivo counting methods well-established and 

data is available for bounding intakes of MAPs and MFPs. 

–Proposed to use Cs-137 to estimate uptakes of MAPs and MFPs

–NIOSH modifies approach based on SC&A’s findings

• NIOSH proposes Be-7 for MAPs

–Using intake ratios based on air emission measurements

–SC&A agrees with method, but questions availability of source data, as well 

as the use of air emissions data (how representative of actual workplace MAP 

ratios?). 

–NIOSH recently performed onsite data capture for applicable documentation 

and data.
MAPs: Work Group review/actions

• WG found need for NIOSH to better define its model for using Be-7 in vivo 

data for MAP exposures.

• NIOSH actions: Proposed DR model needs to address the following:

– Availability and sufficiency of Be-7 bioassay data, post-1975

– Rationale for ratios from air emissions data and why ratios would be bounding 

for all MAP nuclides and forms, over time.

– Type of emissions monitoring (continuous or integrated)

– Criteria for inclusion in in vivo program and whether it changed over time

– Remaining questions regarding “hold up” of MAP air emissions

– Availability of other workplace data to support model
Mixed Fission Products (MFPs): Work Group review/actions

Issue Status, MFPs: 

• SC&A concerned about NIOSH proposed use of Cs-137 based 

reactor ratios (from OTIB) for non-reactor nuclear facilities. 

• NIOSH agrees and sought additional onsite data to support use of 

Cs-137 ratios at CMR, but was unable to locate useable data.

• NIOSH observes, however, that it has located considerable 

operational documentation that supports its premise that LANL 

exercised a “robust” health physics program during the period in 

question and that “appropriate” bioassay methods were available 

during that time. 

• SC&A finds this response inadequate because its basis is largely 

program reliability.
MFPs: Work Group review/actions

• WG found need for NIOSH to define and support its model for using 

Cs-137 in vivo data (within OTIB-062 coworker model) for MFP exposures.

• NIOSH actions: Provide consideration of following issues:

– Demonstrate that intakes derived from Cs-137 are bounding of all MFPs

– Criteria for inclusion in in vivo monitoring program and whether it changed 

over time

– Demonstrate that different types of exposure scenarios for MFP exposure in 

CMR, TA-48, and TA-50, can be bounded using this approach.
SEC Issue 2: DR approach for exotic radionuclides

Description of Issue:

• NIOSH’s ER indicates that “exotic” radionuclides (e.g., Np, Cm, Ac) were 

handled, controlled, and monitored in a manner equivalent to that of the 

primary actinides, e.g., plutonium, uranium, and americium. 

• NIOSH concludes that site-wide bioassay data for these primaries can be 

used to estimate intakes for missing exotics in coworker approach.

SC&A questions whether:

• Ratios of exotic to primaries are known, constant, operationally equivalent

• Ratios representative given exotic “campaigns” vs. routine usage of 

primaries

• Data adequate to determine time, duration, conditions of exposure
Exotics: Work Group review/actions

• At its May 14, 2012, meeting, WG found that NIOSH should provide 

additional supporting information for its proposed model.

• NIOSH actions: 

– NIOSH should document approach for using uranium and plutonium data to 

bound all exotic radionuclides (for bio-assayed and unmonitored workers)

– Review LANL technical basis document for internal dosimetry

– Review reports on topic identified by petitioner

– Ensure that approach addresses all “exotics”
SEC Issue 3: Completeness and reliability of in vitro and in vivo 

data, and adequacy of NIOSH coworker model

Description of Issue:

• NIOSH developed OTIB-0062 applying coworker data for Pu239, Pu-238, uranium, tritium, and Cs-137, in some cases 

substituting for unavailable dose data for MAPs, MFPs, and 

exotic radionuclides. 

• SC&A has remaining concerns with MFP, MAP and exotic 

coworker models
Coworker model: Work Group review/actions

Issue Status:

• NIOSH received updated in vivo database with additional results, but not 

significant increase in total Cs-137 data; 

• NIOSH assumes that where no Cs-137 data reported, exposure was below 

MDA. 

• NIOSH indicates that considerable operational documentation suggests 

“robustness” of LANL health physics monitoring program to ensure workers 

who should have been monitored, were monitored, for time period in 

question. 

• SC&A finds this response inadequate because it is largely based on program 

reliability.

• Remaining actions on coworker models for MAPs, MFPs, and exotics are 

dependent on NIOSH responses on SEC issues 1 and 2.
SEC Issue 4: DR approach for neutron exposures

Description of Issue:

• NIOSH proposes the use of neutron-to-photon dose ratios to bound neutron 

dose prior to 1980 (after 1980, recorded neutron doses are considered to be 

sufficiently accurate, relying on a combination of TLD and NTA film data). 

• NIOSH indicates that area-specific neutron correction factors (NCFs) used at 

LANL can be employed in DR to bound neutron doses for workers in specific 

facilities. 

• SC&A questions whether the proposed n/p values listed in the TBD would 

bound neutron doses for 1976-1979, questioning the 1) representativeness of n/p 

values; 2) accuracy of measured neutron doses; and 3) reliability of NTA film data 

given fading phenomenon. 

Issue Status:

NIOSH validated that operational changes were not significant for 1976-1979, 

compared with 1980-1982, permitting NIOSH to back-extrapolate neutron data. 

Further analysis of historic neutron measurements and data capture at LAMPF 

shows proposed n/p values are bounding. WG closed issue on May 14, 2012.
SEC Issue 5: DR approach for workers adjacent to 

LAMPF/LANSCE retention pond/beam stop 

Description of Issue:

• Former maintenance workers at LAMPF/LANSCE claim their work location 

adjacent to Target Area-A beam stop and near retention pond exposed them 

to both external and internal radiation. 

• Issue not addressed in ER. 

• Worker badging found adequate for limited external radiation outside of 

beam stop. However, presence of tritium in retention pond may have led to 

an inhalation dose due to immersion in airborne vapor.

Issue Status:

NIOSH obtained concentration data for retention pond for time period in 

question. 

WG action:

NIOSH to estimate bounding tritium dose from pond to nearby workers.
SEC Issue 6: DR approach for Special Tritium Compounds

Description of Issue:

NIOSH acknowledges in ER that LANL handled STCs and organically bound 

tritium compounds and that DR can be accomplished applying OTIB-066. 

SC&A questions whether insoluble STCs have been adequately characterized 

and that DR can be accomplished using available site-specific data.

Issue Status:

NIOSH reviewed two classified examples of STC activities and found no basis 

for altering its conclusion regarding dose reconstructability. SC&A reiterated 

need to conduct source-term characterization and ascertain exposure 

potential.

WG Action:

NIOSH will follow-up on characterizing source terms, the potential for 

exposure, and who would be assigned dose applying OTIB-066.
SEC Issue 7: Issues related to unmonitored exposure of support 

service personnel 

Description of Issue:

Based on SC&A interviews, it is apparent that routine bio-assaying of security 

guards, firefighters, and other support service workers, was limited and in 

some cases, discontinued during the 1990s. Given the broad, site-wide 

access for these workers, and the uncertainty regarding their exposure 

potentials, it is not clear how NIOSH will dose reconstruct with sufficient 

accuracy.

Issue Status:

NIOSH’s ER provision applies the coworker dose distribution based on OTIB062, as well as substitute actinides for “exotics,” for all support workers who 

were not bio-assayed. Resolution of this issue links to Issues 1-3.

WG Action:

NIOSH to explain drop-off in bioassay data over time and whether justified 

from radiological standpoint.
SEC Issue 8: Petitioner Issues

Description of Issue:

Petitioners have identified what they consider SEC issues or questions as part of 

petition or during WG meetings. These include discrepancies or inconsistencies in 

the ER, exotic radionuclide exposures at the firing sites, badge access to 

radiological areas, application of NIOSH’s occupational environmental model, and 

radiological exposure to firefighters from the Cerro Grande fire.

Issue Status: 

NIOSH committed to address all petitioner issues; including: 

• NIOSH will address exotics at the firing sites based on ER approach; however, 

WG concerned whether coworker model will bound potential exposures.

• NIOSH will not use badge access to determine dose.

• NIOSH has reviewed re-suspension issue for Cerro Grande, and has issued 

white paper; however, WG concerned about power loss and filter clogging 

issues affecting reported sampling results.

• NIOSH believes that even though LANL has often had “campaign-based” work 

like NTS, significant differences exist between the two sites; LANL had more 

robust HP program during time period.
Petitioner Issues: Work Group review/actions

Work Group concluded more follow-up needed for following petitioner 

issues:

• Firing site: NIOSH will demonstrate that coworker model will bound 

potential exposures from re-suspension in firing site and other “release 

points.”

• Cerro Grande fire: SC&A will review NIOSH white paper.

• NIOSH will check petitioner report to assure a response has been provided 

to all other issues.