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DCAS SEC 210 

DCAS External Memorandum 

Division of Compensation Analysis & Support 

To: Kansas City Plant SEC Working Group 

From: Peter Darnell, DCAS Health Physicist 

Pat McCloskey, ORAU Team Health Physicist 

Subject: SEC Issues Matrix Responses to 1, 7, 11, 12, 15 and 17

Date: June 11, 2015 

The following update is provided for the Working Group. NIOSH received SC&A’s Issue 13 (MgTh) comments on 5/12/15 and will respond separately. SC&A is planning a data capture trip to 

address Issue 18 (Incidents); therefore, NIOSH will wait for additional information from SC&A 

before responding. To address Issue 20 (Tritium), NIOSH has revised the white paper Tritium 

and Ni-63 at KCP and provided it to the Working Group. 

Issue 1 - Data Completeness, Legibility, and Accuracy 

At the January 20, 2015 Working Group meeting, NIOSH committed to provide the WG with a 

proposed sampling plan for how it intends to validate the electronic database with the raw 

records for both internal and external dose (external dose is also addressed in Issue #9). 

Following WG agreement, NIOSH would conduct the sampling review and provide results. 

NIOSH response 

The database (SRDB 111136) contains over 15000 external and 2810 internal monitoring 

records for 4500 workers, and spans the years from 1950 to 2010. The database has 

workers identified by Social Security and employee ID numbers. NIOSH used the 

database’s monitoring data to build an internal coworker model from 1959 – 1971 
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urinalysis data, and an external coworker model from 1950 – 1990 data in the KCP Site 

Profile (SRDB 20217). 

NIOSH plans to extract data from DOE-supplied dose records in the 691 NOCTS claims 

currently available. These NOCTS claims contain 223 external and 95 internal dosimetry 

records. NIOSH will compare this raw data to that in the database previously used for 

the coworker model. NIOSH will review each step of the data entry process to validate 

accuracy, and will perform a comparison of NOCTS and KCP raw records. 

NIOSH will also compare database information to records in the SRDB such as REMS and 

incident reports where appropriate. 

NIOSH responses to Issues 7, 15 and 17 of the memo “SC&A’s Evaluation of NIOSH’s January 

2015 Response to KCP SEC Matrix Issues 7, 15, 17, 18, and 20” dated 4/20/15 

Issue 7 – Radioactive Waste 

In their memo, SC&A states the following: Interviews conducted at KCP in March 2015 indicated 

that unmonitored laborers collected the uranium and Mg-Th cuttings and chips from the lathe 

machines for placement in 55-gallon drums, which were then transported to the KCP central 

waste facility. These wastes were coated in lathe oil and were apparently collected from under 

the machine and from the floor, and loaded into the drums using a “pitchfork” implement. 

Laborers were neither badged nor bioassayed. It was also noted that while worker movement 

into and out of these radiological operating areas was restricted by security access badges until 

the late 1960s-early 1970s, this restriction was relaxed thereafter to anyone with a general “Q” 

clearance. While there was clearly an exposure potential, a remaining question is whether it 

can be considered comparable to the lathe operators, who were monitored. 

SC&A recommends that NIOSH review the relative exposure potential of the custodial/laborers 

who routinely collected and drummed contaminated waste, as compared with the operators 

who conducted the machining of depleted uranium (DU) and Mg-Th, with an objective of 

informing the WG as to whether these exposures are comparable (or for the former, lower) and 

can therefore be adequately bounded using available monitoring data. 
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NIOSH response 

NIOSH reviewed KCP job descriptions of custodians and laborers (e.g. SRDB 137737, 

137790) from recently obtained documents. NIOSH also reviewed the notes from the 

SC&A referenced interviews, and the notes from past interviews of some of the same 

workers (SRDB 126958, 127876). SC&A referenced statements from four former 

workers and concluded that they were not monitored. NIOSH, however, reviewed the 

existing personnel monitoring database and found internal and external monitoring 

records for two of the four interviewees. NIOSH has also reviewed access lists and 

medical releases that authorized the interviewees to enter specific work areas (NOCTS 

40995, 29761, 32283). 

NIOSH has reviewed safety procedures that span the years 1951-1975 (SRDB 128346, 

14690, 14685, 128440 p. 35, 108264 p. 2 and 44, 128181 p. 2-7, 128443, 128433, 

128155) that prescribe the use of PPE, medical surveillance, wet methods, and industrial 

hygiene best work practices. These procedures, corroborated by interviewees, were 

implemented by KCP to control the activities of anyone with access to the work area for 

waste handling. 

The greatest potential for worker exposure at KCP was during the DU machining 

operations from 1958 to 1971. During these DU operations, KCP implemented an area 

and personal monitoring program. The monitoring data from this period indicate 

adequate work control and provide supporting evidence that the methods in the ER 

plausibly bound exposures during this period. 

NIOSH reviewed SC&A’s 2007 report “A Focused Review of Operations and Thorium 

Exposures at the Dow Chemical Company Madison Plant” (SRDB 53614), that describes 

dosimetric implications of working with the same Mg-Th Dow supplied to KCP. This 

report provides data from air samples collected in the breathing zone of workers that 

were “drumming” Mg-Th powder. The sample results for this drumming activity were 

given as 15 μg/m3. Using the Th-232 specific activity (1.1E-7 Ci/g) yields an equivalent 

air concentration of 1.65 E-12 μCi/ml. NIOSH believes that this drumming activity 

represents a worst-case exposure scenario for waste handlers, and it is not likely that 

KCP waste handlers were exposed to a higher concentration on a 2000-hour timeweighted-average (TWA) basis. 
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The KCP ER has methods for bounding doses during operations in Section 7. Worker 

categories were presented in the ER to differentiate the varying exposure potential for 

machine operators, general laborers, supervisors and others. For example, NIOSH will 

assume that general laborers were exposed to an air concentration half that of the 

operators (0.5 * 3E-11 or 1.5E-11 μCi/ml).

NIOSH has reviewed the exposure potential of the custodial/laborers who collected and 

drummed contaminated waste, and believes some of the workers in this category were 

monitored, and will use that data where available to reconstruct doses.

Based on levels of Th observed during drumming operatons at Dow and KCP’s Health 

and Safety procedures that included: 1) working with materials that were maintained 

wet and 2) the required use of KCP provided PPE and IH best practices, NIOSH concludes

that the general laborer category of Mg-Th worker described in the ER, adequately 

bounds these exposures at an air concentration of 1.5 E-11 μCi/ml, and 2000 hours of 

exposure per year.

Issue 15 – Thorium oxide operations

In their memo, SC&A provides the following assessment:

“SC&A’s review of KCP materials inventory data indicates that the listing of “unalloyed” 

thorium was apparently an artifact of the site’s calculation of how much actual “pure” 

thorium made up the inventory of Mg-Th being processed. This was verified by 

comparing a sample of historic KCP inventory values from the 1970s, obtained and 

cleared by KCP, with those in the NMMSS database at DOE headquarters. Recorded 

values matched from both inventory ledgers. Other than Mg-Th, thorium being used at 

KCP was historically in gram quantities and of a laboratory scale, was handled under 

hoods, and did not present an exposure potential. SC&A recommends that this issue be 

closed by the WG.”

NIOSH concurs with SC&A’s assessment.

Issue 17 – D&D activities
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SC&A believes it is clear from the March 2015 onsite interviews with former workers, that at 

KCP, laborers had a substantial role in cleaning up floors, walls, and equipment, whether on a 

day-to-day basis, or in periodic room cleanups. A clear distinction was made between 

“laborers” who handled cleaning duties and various crafts responsible for moving, maintaining, 

and operating equipment, such as lathes. Some laborers wore external dosimeters (it was said 

to be mandatory in Mg-Th areas), but none of the former laborers interviewed indicated any 

routine bioassay. While the “KCP machine repair” was responsible for taking equipment apart, 

the laborers were responsible for cleaning the internal parts of that equipment, It is clear that 

non-bioassayed laborers had a substantial D&D role at KCP for the periodic room and 

equipment cleanups that took place at the plant; it is not clear whether their exposure 

potential was the same as the DU and Mg-Th machinists, themselves. 

SC&A recommends that NIOSH review the relative exposure potential of the custodial/laborers 

who routinely cleaned contaminated equipment and areas, as compared with machinists who 

did the machining of DU and Mg-Th, with an objective of informing the WG as to whether these 

exposures are comparable (or for the former, lower) and can therefore be adequately bounded 

using available monitoring data. 

NIOSH response 

NIOSH has reviewed the notes from the referenced interviews and the notes from past 

interviews of some of the same workers. SC&A referenced statements from four former 

workers and stated that they were not internally monitored. NIOSH, however, reviewed 

the existing personnel monitoring database and found internal monitoring records for 

two of the four interviewees. NIOSH has also reviewed access lists and medical releases 

that authorized these interviewees to enter specific work areas. 

NIOSH has reviewed safety procedures that KCP implemented to control the activities of 

anyone with access to the work area, and documents that describe KCP’s 

decontamination procedures. These procedures corroborate the interviewee’s 

recollection of, among other things; radioactive materials maintained wet and the use of 

respirators while performing decontamination work. (Same SRDB references listed 

above) 
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The greatest potential for worker exposure at KCP was the DU machining operations 

from 1958 to 1971. During these DU operations, KCP implemented a robust area and 

personal monitoring program. The monitoring data from this period indicates adequate 

work control and validates the bounding methods in the ER. 

NIOSH reviewed SC&A’s 2007 report “A Focused Review of Operations and Thorium 

Exposures at the Dow Chemical Company Madison Plant” (SRDB 53614), that describes 

dosimetric implications of working with the same Mg-Th Dow supplied to KCP. This 

report provides data from air samples collected in the breathing zone of workers 

performing aggressive activities with Mg-Th that would have likely exceeded the 

airborne generating capacity of KCP’s decontamination work. These vigorous activities 

included open-wheel surface grinding, air-operated vibration sanding and buffing. For 

comparison, the highest observed air concentration in the workers’ breathing zone 

while performing these airborne generating activities at Dow was 3.9 E-12 μCi/ml. 

NIOSH believes that this Dow work represents a worst-case exposure scenario for D&D 

type work, and it is not likely that KCP workers were exposed to a higher concentration 

on a 2000-hour TWA basis. 

The KCP ER has methods for bounding doses during operations in Section 7. Worker 

categories were presented in the ER to differentiate the varying exposure potential for 

machine operators, laborers, supervisors and others. NIOSH has reviewed the exposure 

potential of the custodial/laborers who cleaned contaminated equipment and areas, 

and believe some of the workers in this category were monitored, and will use that data 

where appropriate to reconstruct doses. 

Based on levels of Th observed during grinding/sanding operatons at Dow and KCP’s 

Health and Safety procedures that included: 1) working with materials that were 

maintained wet and 2) the required use of KCP provided PPE and IH best practices, 

NIOSH concludes that the general laborer category of Mg-Th worker described in the ER, 

adequately bounds these exposures at an air concentration of 1.5 E-11 μCi/ml, and 2000 

hours of exposure per year. 

Additionally, NIOSH has reviewed a KCP procedure used for the decontamination of 

equipment contaminated with beryllium or radioactive material (SRDB 137215 p. 23) 

which may contain the controls for the work described by one March 2015 interviewee. 
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NIOSH response to the memo “SC&A’s Evaluation and Closure of KCP SEC Matrix Issues 11 

and 12; Neutron Dose” dated 4/21/15 

In this memo, SC&A documented their review of the NIOSH Issues Matrix response, and 

independently evaluated the supporting KCP dosimetry data. In conclusion SC&A states: 

“In view of this analysis, SC&A found that NIOSH’s use of a neutron dose of 0.154 

rem/year for KCP workers that may have been exposed to neutrons is reasonable and 

claimant favorable. SC&A considers the present KCP SEC neutron dose-related issues 

addressed and the issues have been closed by the Advisory Board.”

NIOSH concurs with SC&A’s conclusion.

Reviewed and Concurred by: 

_____________________________________ Date: _06/19/2015______ 

Peter Darnell, CHP, RRPT 

Division of Compensation Analysis and Support 

[Signature on File]