Dow Chemical Company

Special Exposure Cohort

LaVon B. Rutherford, CHP

Division of Compensation Analysis and Support

March 2015

Richland, Washington

 
Facility Designation

 Dow Chemical Company

 Atomic Weapons Employer facility in 

Pittsburg, CA

 Covered time period: 1947-1957

 Atomic Energy Commission (AEC) contract for 

small scale research on uranium recovery 

from phosphate residues
Background 

 Petition SEC-00216 received: June 12, 2014

 Qualified for Evaluation: August 5, 2014

 Class evaluated for all workers during covered 

period (1947-1957)

 NIOSH recommended class:

• All workers at Dow Chemical Company in Pittsburg, 

California, from October 1, 1947 through June 30, 1957, 

based on actual contract operations dates
Site History

 AEC contracted with DOW to study uranium 

extraction from various residues and raw 

materials from phosphate industry

 Contract lasted more than 9 years

 Small-scale extraction experiments, bench top, 

and pilot-plant scale

 Successful processes to be scaled up at other 

sites
Site History (cont.) 

 Pittsburg site is ~ 513 acres, 41 used by DOW

 Up to 7 rooms in DOW’s research laboratory 

building used for AEC work

 DOW commercial operations at site not 

associated with AEC work

 About 100 workers total involved in project 

at some point during contract operations
Site History (cont.) 

 Processes investigated :

 Precipitation 

 Ion exchange

 Solvent Extraction

 Raw materials: 

 Phosphate industry residues and ores

 Phosphoric acid

 Phosphate rock

 No indication that thorium separations took 

place under this AEC contract
Dose Reconstructions

NIOSH Claims Tracking System 

(March 3, 2014)

 Submitted to NIOSH 1

 Within the SEC period (1947–1957) 1

 Dose reconstructions completed 

outside SEC period 0 

 Containing internal dosimetry 0 

 External dosimetry 0 
Sources of Available Information

 NIOSH Site Research Data Base: 166 documents 

 Claim file

 DOW headquarters

 Landauer 

 Department of Energy Office Scientific Technical 

Information

 Former worker interviews (3)

 Other standard data searches conducted
Potential Exposures

 Internal:

 Uranium and progeny if contained in raw materials

 Thorium and progeny if contained in raw materials – 

there was no specific research objective to separate 

thorium 

 Radium and polonium typically are not carried into 

the phosphoric acid during phosphate rock 

processing

 External:

 Beta and photon from uranium and thorium 

daughter nuclides in the decay chains
Personal and Area Monitoring Data 

 No internal or external personnel monitoring 

available

 No air sampling or area survey data available

 Source-term information insufficient

 Process-information insufficient

 No medical occupational exposure 

information available
Feasibility of Dose Reconstructions

 Available monitoring records, process 

information and source-term data are 

insufficient to complete dose reconstructions 

with sufficient accuracy for the evaluated 

worker class
Health Endangerment

 The evidence reviewed in this evaluation indicates that 

some workers in the class may have accumulated 

chronic radiation exposures through intakes of 

radionuclides and direct exposure to radioactive 

materials

 Consequently, NIOSH is specifying the health may have 

been endangered for those workers who were 

employed for a number of work days aggregating at 

least 250 work days within the parameters established 

for this class or in combination with work days within 

the parameters established for one or more other 

classes of employees in the SEC
Proposed Class Definition

• All Atomic Weapons Employer employees who 

worked for the Dow Chemical Company in 

Pittsburg, California, from October 1, 1947 

through June 30, 1957, for a number of work 

days aggregating at least 250 work days, 

occurring either solely under this employment 

or in combination with work days within the 

parameters established for one or more other 

classes of employees included in the Special 

Exposure Cohort.
Summary 

Feasibility Findings for SEC-00216 – Dow Chemical, Pittsburg CA

(October 1, 1947 through June 30, 1957)

Exposure Source Reconstruction

Feasible 

Reconstruction Not

Feasible 

Internal - Uranium X 

External X 

Gamma X 

Beta X 

Neutron N/A

Occupational medical XraysX 
Questions?