W.R. Grace and Company

Special Special Exposure Exposure Cohort

Evaluation Report

James W. Neton, Ph.D., CHP

Associate Director for Science

National National Institute Institute for Occupational Occupational Safety and Health

Division of Compensation Analysis and Support

August 2011

Richland, WA
Background

 W.R. Grace is located in Curtis Bay, MD Originally 260 acres, now 109 acres Original site owned by Davison Chemical Com

 W.R. Grace bought Davison Chemical in 1954

 Rare Earths Inc., entered entered AEC contract contract in 1955

transferred to W.R. Grace in ~ 1957

 W.R. Grace to extract extract thorium thorium from monazite monazite 

AEC at two facilities (Wayne, NJ and Curtis Ba
Background—cont.

Building 23

Former

monazite

processing

area
Site Operations

 Process AEC‐owned monazite ore to extract

thorium thorium and rare earths

 Monazite contains ~ 6% thorium oxide 95% of thorium in ore to be extracted

• 5% remained in residual material buried on‐site

 Total of 997 tons of monazite processed bet

May 1956 and Spring 1957

 Problems with process led to contract termi
Site Operations—cont.

 All thorium work done in part of Building 23

• Monazite Monazite ground in ball mill• Reacted with concentrated sulfuric acid• Crystallizer tanks• Rake classifier (crude separation)• Filtering Filtering of Th‐bearing bearing solution solution and separation separation f

unreacted material

• Precipitation and reaction to end product (thoriu

h dy rate)

• Finished product shipped to Curtis Bay Governm

Storage Depot
Petition Overview

 December 21, 2010: NIOSH received a

83.13 petition

 February 17, 2011: Peti it on qualified 

evaluation

 July 14, 2011: Evaluation Report appr
Proposed and Evaluated SEC C

 Petitioner proposed class definition:

• Chemical operators, bar mill operators, and pot op

who work de with or on rotary dryers, pill machines

mixes (sieves), hydroxide dryer, blenders #1 and #3

906 and 902 material, Red Dog and Vanadium mate

Specialty Specialty, Monasito Monasito [sic], LDI Plants, Tech Center, B

B

109, 193, 194, and 224 at W.R. Grace and Company

Bay, Maryland, from 1955 through 2009.

 NIOSH evaluated evaluated class

• All Atomic Weapons Employees who worked at W.R

and Company in Curtis Bay, Maryland, for the operperiod from January 1, 1955 through December 31, 

the residual radiation period from January 1, 1959 October 31, 2009.
Petition Bases and Concern

 Unmonitored workers

• Petitioner presented an affidavit indicat

that all work performed at the W.R. Grafacility in Curtis Bay, MD between 1953was conducted without the use of dose

monitoring equipment or all monitoring 

was destroyed or is missing
Sources of Available Informati

 ORAU Technical Information Bulletins Case files in NIOSH database database NIOSH Site Research Database

• 132 documents documents pertaining pertaining to W R. . Grace

 Documentation and/or affidavits provided 

petitioner

 Interviews – one former worker, one petiti

representative

 Various electronic databases (DOE, NRC)
Previous Dose Reconstructio

NIOSH OCAS Claims Tracking System

Information available as of August 2, 2011

 W.R. Grace MD claims submitted to NIOSH 1 Claims that meet the class definition definition 1 Dose reconstructions completed for claims

that meet the class definition 1

 Claims containing internal dosimetry 0

 Claims containing external dosimetry 0
Potential Internal Radiation Exp

 Monazite processing resulted in worke

exposures from thorium, uranium and t

decay products

• Inhalation and ingestion of dust from

operati i ll d tions, especially dry-h dli f handling of materials 

• Inhalation and ingestion of re Inhalation and ingestion of re -suspended suspended 

particles in work areas 

• Ingestion of particles from eating and dr

in work areas 

• Inhalation of gaseous decay products (ra

and thoron) 
Potential External Radiation Exp

 Photon/beta Photon/beta exposure exposure from thorium thorium and

uranium and decay products present in mo

sands during milling milling and extraction extraction operat

operat
Availability of Internal

D i os metry D t a a

 Operational period:

• No internal dosimetry data, air sample data or

sufficient source term or process data have bel d ocate

 Residual Period:

• Air sample data from Rare Earths/W.R. Grace, 

NJ from 1959 and 1961 (shared contract with WGrace, MD)

• 1986 and 2000/2001 site characterization data 

FUSRAP
Availability of External Dosimetry 

 Operational period:

• No external personnel or area monitoring data

(including medical X‐rays) have been located

 Residual period:

• Dose rate data from 1986 site characterization 

FUSRAP


Approach to Residual Period D

Reconstruction

Internal:

• Use of air concentration values at beginning an

during the residual residual period to calculate calculate intake r

• Assume exponential relationship to calculate i

rates for intervening time periods

 External:

• Radiation dose rate data measured in 1986

• Application of depletion factor determined ab
Evaluation Process

 Two‐prong test established by EEOICPA an

incorporated into 42 CFR . . . § 83 13 . (c)(1) a

C.F.R. § 83.13 (c)(3):

1. Is it feasible to estimate the level of radiation 

of individual members of the class with sufficiaccuracy?

2. Is there a reasonable reasonable likelihood likelihood that such radi

radi

dose may have endangered the health of mem

the class?
Feasibility of Dose Reconstruct

The process and source term information pr

insufficient information to estimate dosesassociated with monazite processing with

sufficient accuracy for workers at W.R. GracCompany.
‐

F ibilit Fi di f W R G d C P titi

Summary

Feasibility Findings for W. R. Grace and Company Petitio

May 1, 1956 – January 31, 1958

Source of Exposure Reconstruction Reconstru

Feasible NOT Fea

Internal

‐ all radionuclides X

External

‐ Photon X

‐ Beta X

‐ Neutron N/A

‐ Occupational

Medical X‐ray N/A
‐

F ibilit Fi di f W R G d C

Summary—cont.

Feasibility Findings for W. R. Grace and Company

February 1958 – October 2009

Source of Exposure Reconstruction Reconstr

Feasible NOT Fea

Internal

‐ all radionuclides X

External

‐ Photon X‐ Beta X

‐ Neutron N/A

‐ Occupational

Medical X‐ray N/A
Health Endangerment

 The evidence reviewed in this evaluation

indicates that some workers in the class m

have accumulated chronic radiation expos

through intakes of radionuclides and direc

exposure to radioactive materials.

 Consequently, NIOSH is specifying that hea

may have been endangered for those work

covered by this eval ti ua on who were empl 

for a number of work days aggregating at l

250 work days within the parametersestablished for this class or in combination 

work days within the parameters establish

one or more other classes of emp y lo ees in 

SEC .
Proposed Class

All Atomic Weapons Employees who workany building building or area at the facility facility owned b

W.R. Grace and Company in Curtis Bay,

Maryland, for the operational period from 

1, 1956 through January 31, 1958, for a nuof work days aggregating at least 250 work occurring either sol l e y under this employm

or in combination with work days within t

parameters parameters established established for one or more ot

classes of employees in the Special Exposu

Cohort.
Recommendation

 For the period May 1, 1956

– January 31, 1

NIOSH finds that radiation radiation dose estimates estimates c

be reconstructed for compensation purpos

Class Feasibility Health Endang

Ma

y

1, 1956

– Januar

y

31, 1958

N

o

Yes