Los Alamos National Laborato

Revision to the

Special Exposure Cohort

Petition Evaluation Report

SEC‐00109

James W. Neton, Ph.D., CHP

Associate Director for Science

National Institute for Occupational Safety and Health

Division of Compensation Analysis and Support

September 2012

Denver, CO
Background

 Previous NIOSH evaluations (SEC‐00051, S

00061, and SEC‐00170) have established Sthat include all employees from March 15, 

through December 31, 1975

 Basis for the class was infeasibility of inter

dose reconstruction for a number of

radionuclides, including:

• Am, Cm, Np, Th, Sr• Mixed fission and activation products
Background—cont.

 The evaluation report for SEC‐00051 recog

that the identified dose reconstruction issu

might still exist for the post‐1975 period

 On this basis, NIOSH qualified the current

petition (SEC‐00109) for evaluation
LANL Operations: 1976‐200

 Weapons development and testing

 Critical assemblies, reactors, and reactor

development

 Accelerators, x‐ray equipment, and radiog

sources

 Biomedical research

 Project Sherwood and fusion research

 Waste treatment and disposal
Potential Radiation Exposur

During the Class Period

 Internal sources of exposure

• Primary radionuclides

—Cs‐137, H‐3, Pu‐238, Pu‐239, uranium

• Exotic radionuclides as defined in SEC‐00051

—Mixed fission and mixed activation products

—Ac‐227, Am‐241, Cm‐244, Np‐237, Pa‐231, Sr‐90/Y‐9

230, Th‐232

 External sources of exposure

• Photon, beta, and neutron exposure from

accelerators, reactors, x‐ray machines, and

radioactive materials
Previous Dose Reconstructio

NIOSH OCAS Claims Tracking System

Information available as of August 8, 2012

 LANL claims submitted to NIOSH 1 Claims with employment during the period

evaluated (01/01/1976‐12/31/2005) 

• Dose Reconstructions completed 627 (73%)

 Claims with start dates after 12/31/1975 

 Claims containing internal monitoring data 

 Claims containing external monitoring data 
Petition Overview

 April 3, 2008: 42 CFR Part 83.13 petition receiv

(SEC‐00109)

 May 29, 2008: Petition qualified for evaluatio

 January 22, 2009: NIOSH issued the initial SEC

00109 Petition Evaluation Report (Rev. 0)

• Class evaluated: Service Support Workers from Jan

1976 through December 31, 2005

• NIOSH concluded that sufficient information was

available for dose reconstructions

• No additional SEC class was recommended at that 
Petition Overview—cont.

 Following additional review of the available d

NIOSH now finds that it lacks sufficient inform

to demonstrate feasibility of internal dose

reconstruction for some radionuclides, includ

• Certain tritium compounds• Fission and activation products

• Thorium• Exotic alpha emitters, e.g., Am‐241, Np‐237, Ac‐22

231, and Cm‐244
Petition Overview—cont.

 August 13, 2012: NIOSH issued a revision t

SEC‐00109 Petition Evaluation Report (Rev

• Revised previous decision to not recommend a 

• Class now recommended for all workers at LAN

January 1, 1976 through December 31, 1995

• End date selection is based on NIOSH’s presum

that LANL would have been in full compliance 

CFR 835 by that date

• NIOSH is continuing to evaluate the post‐1995 
Proposed Approach to Intern

Dose Reconstruction (rev. 0

 Extensive monitoring data available for rou

handled radionuclides (i.e., U, Pu, Cs, and t

• Coworker models established in OTIB‐0062

 Sparse monitoring data available for non‐

routinely handled radionucldes (i.e., exotic

mixed fission, and activation products)

 Approach to reconstruction relied on use o

and Cs coworker data as surrogates for exp

to non‐routinely handled radionuclides
Issues with Proposed Approa

 Original assumption that exotic radionuclides 

handled, controlled, and monitored in a simil

manner to U, Pu, and Cs could not be substan

 Exposures to exotics might be on an intermitt

experimental basis leading to episodic exposu

are not represented by a chronic exposure mo

 Comparability of operations that used exotics 

been established

 Short duration exposures might not have simi

engineering controls in place as well‐establish

operations
Feasibility of Internal Dose

Reconstruction

 The available monitoring records, process

descriptions, and source‐term data are inadeq

complete internal dose reconstructions withsufficient accuracy for the evaluated class of

employees during the period January 1, 1976 

December 31, 1995

 Based on a presumption of compliance with 1

835, NIOSH finds that dose reconstruction is l

feasible by January 1, 1996

 NIOSH is continuing to evaluate feasibility for 

post‐1995 period
Feasibility of External Dose

Reconstruction

 Majority of all workers monitored for photons aft

 Personnel dosimeters were capable of measuring 

exposures

 Field beta measurements were taken in conjuncti

photon surveys

 Neutrons monitored prior to 1980 can be assesse

appropriate N/P ratios

 Neutron exposures after 1980 measured using a

combination of albedo and NTA film

 Occupational medical dose reconstruction possib

ORAU‐TBKS‐0013
Summary of Feasibility Findin

(1976‐1995)

Source of Exposure Reconstruction Feasible Reconstruction N

Internal X

‐ Pu, U X‐ H‐3, MFP, MAP, Th,

Am‐241, Np‐237, Ac‐

227, Pa‐231, Cm‐244

X

External X 

‐ Gamma X‐ Beta X

‐ Neutron X‐ Occupational

Medical X‐ray X
Health Endangerment

 The evidence reviewed in this evaluation indic

that some workers in the class may haveaccumulated chronic radiation exposures thro

intakes of radionuclides.

 Consequently, NIOSH is specifying that health 

have been endangered for those workers covethis evaluation who were employed for a num

work days aggregating at least 250 work days 

the parameters established for this class or incombination with work days within the param

established for one or more other classes of

employees in the SEC.
NIOSH Recommendation

All employees of the Department of Energy

predecessor agencies, and their contractor

subcontractors who worked at the Los Alam

National Laboratory in Los Alamos, New M

from January 1, 1976 through December 31for a number of work days aggregating at le

250 work days, occurring either solely unde

employment or in combination with work d

within the parameters established for one 

more other classes of employees in the Spe

Exposure Cohort.
NIOSH Recommendation‐con

 Rationale for including all workers:

• NIOSH has determined that, due to undocume

worker movements across the site and limited

claimant‐specific information pertaining to wo

locations, it is unable to eliminate any specific from potential exposure scenarios based on as

work location.
NIOSH Recommendation‐con

 For those not included in the SEC:

• NIOSH intends to use any internal and externa

monitoring data, and medical doses that may available for an individual claim (and that can 

interpreted using existing dose reconstruction

processes or procedures). Therefore, partial doreconstructions for individuals employed at Lo

Alamos National Laboratory during the period 

January, 1976 through December 31, 1995, bu

not qualify for inclusion in the Special ExposurCohort, may be performed using these data as

appropriate.
NIOSH Recommendation‐con

Class Feasibility Health Endang

January 1, 1976 

to 

December 31, 1995 

No Yes