HHS Special Exposure Cohort Determination: 

Blockson Chemical Company, Joliet, Illinois [SEC 00225]

U.S. Department of Health and Human Services Determination Concerning a 

Petition to Add Members to the Special Exposure Cohort

under the 

Energy Employees Occupational Illness Compensation Program Act of 2000 

Determination Concerning a Petition for Certain Employees from 

Blockson Chemical Company

Joliet, Illinois
HHS Special Exposure Cohort Determination: 

Blockson Chemical Company, Joliet, Illinois [SEC 00225]

Page | 2 

I. Determination 

I, Sylvia M. Burwell, Secretary of Health and Human Services (Secretary) (HHS), have 

determined that the employees defined in Section II of this report do not meet the statutory 

criteria for addition to the Special Exposure Cohort (SEC), as authorized under the Energy 

Employees Occupational Illness Compensation Program Act of 2000 (EEOICPA), 42 U.S.C. § 

7384q. 

 December 21, 2016 [Signature on File] 

Date Sylvia M. Burwell

II. Employee Class Definition

All employees who worked in any area at the Blockson Chemical Co. site in Joliet, Illinois, 

during the period from July 1, 1960, through December 31, 1991. 

III. Decision Criteria and Recommendations

Pursuant to 42 U.S.C. § 7384q, to designate a class for addition to the SEC, the Secretary must 

determine, upon recommendation of the Advisory Board on Radiation and Worker Health 

(Board), that

(1) It is not feasible to estimate with sufficient accuracy the radiation dose that the class 

received; and

(2) There is a reasonable likelihood that such radiation dose may have endangered the health 

of members of the class.

The SEC final rule states in 42 C.F.R. § 83.13(c)(1) that it is feasible in two situations to estimate 

the radiation dose that the class received with sufficient accuracy. First, the rule states that 

radiation doses may be estimated with sufficient accuracy if the National Institute for 

Occupational Safety and Health (NIOSH) has established that it has access to sufficient 

information to estimate the maximum radiation dose for every type of cancer for which radiation 

doses are reconstructed that could have been incurred under plausible circumstances by any 

member of the class. Alternatively, radiation doses may be estimated with sufficient accuracy if 

NIOSH has established that it has access to sufficient information to estimate the radiation doses 

of members of the class more precisely than a maximum dose estimate.

In a letter received by the Secretary on October 24, 2016, the Board, pursuant to 42 U.S.C. § 

7384q, agreed with the following NIOSH findings, effectively advising the Secretary that 

radiation doses can be reconstructed with sufficient accuracy for certain employees at the 

Blockson Chemical Company site (Blockson) in accordance with provisions of EEOICPA and the 

SEC final rule.

IV. Determination Findings
HHS Special Exposure Cohort Determination: 

Blockson Chemical Company, Joliet, Illinois [SEC 00225]

Page | 3 

Feasibility of Estimating Radiation Doses with Sufficient Accuracy

The Secretary established the feasibility determination for the class of employees covered by this 

report based upon the findings summarized below: 

• NIOSH has determined that the principal sources of internal radiation doses for the proposed 

class was from exposures to particulate uranium and thorium (and their progeny) through 

inhalation or ingestion of surface or airborne contamination and exposures to radon emitted 

from the radium-bearing phosphogypsum stacks. 

• NIOSH has determined that it is feasible to reconstruct internal radiation doses from resuspended residual Atomic Energy Commission (AEC)-related uranium and thorium and their 

progeny using Blockson employee bioassay data and site workplace contamination survey 

data. 

• Additionally, NIOSH has determined that it is feasible to reconstruct internal doses from 

residual, AEC-related radon using a comparison of Blockson emanation (flux) measurements 

to radon emanation and concentration measurements taken at a similar phosphate production 

facility. 

• Therefore, NIOSH has determined that it is feasible to reconstruct internal radiation doses 

during the petitioned period from July 1, 1960, through December 31, 1991. 

• NIOSH has determined that the principal sources of external radiation doses for the proposed 

class included exposures to surfaces contaminated with natural uranium and thorium (and 

their progeny) and submersion in re-suspended surface contamination. 

• NIOSH has determined that it is feasible to reconstruct external radiation doses using site 

radiological survey data and site source-term information.

• NIOSH finds that it is not applicable to reconstruct occupational medical doses for Blockson 

during the period under evaluation. Because there was no AEC work during the residual 

contamination period, any medical X-rays taken by workers and the resulting radiation doses 

workers received during that time would not be covered occupational exposures. 

• NIOSH determined that it has access to sufficient information to either (1) estimate the 

maximum external and internal radiation dose for every type of cancer for which radiation 

doses are reconstructed that could have been incurred under plausible circumstances by any 

workers at Blockson during the period from period from July 1, 1960, through December 31, 

1991; or (2) estimate the external and internal radiation doses to any workers at Blockson 

during the period from July 1, 1960, through December 31, 1991, more precisely than a 

maximum dose estimate.
HHS Special Exposure Cohort Determination: 

Blockson Chemical Company, Joliet, Illinois [SEC 00225]

Page | 4 

• The Board concurred with NIOSH's determination that dose reconstruction is feasible 

for the class of Blockson workers covered by Petition 00225 for the period from 

period from July 1, 1960, through December 31, 1991, and therefore should not be 

added to the SEC.

Health Endangerment

Because the Secretary established that it is feasible to estimate with sufficient accuracy the 

radiation doses encountered by Blockson employees as specified in this class, a determination of 

health endangerment is not required. 

V. Effect of the Determination

Members of the class of employees covered by this determination and their survivors continue to 

be eligible to submit claims for compensation under EEOICPA. As required for cancer claims 

covering other Department of Energy and Atomic Weapons Employer employees (or Atomic 

Weapons Employees) not included in the SEC, qualified cancer claims under Part B of EEOICPA 

for members of this class will be adjudicated by the Department of Labor, in part, on the basis of 

radiation dose reconstructions, which will be conducted by NIOSH. 

VI. Administrative Review of Determination

The determination provided in this report may be subject to an administrative review within HHS, 

pursuant to 42 C.F.R. § 83.18(a). On the basis of such a review, if the Secretary decides to 

designate the class of employees covered by this determination, in part or in whole, as an addition 

to the SEC, the Secretary will transmit a new report to Congress providing the designation and the 

criteria and findings on which the decision was based.