United Nuclear Corporation Air Concentration Data for 1961 and 1962 

Lara Hughes
 

NIOSH/DCAS
 

November 2011
 

The problem: 

Routine bioassay sampling was done for workers at the United Nuclear Corp. facility through its 

entire covered period with the exception of 1961 and most of 1962. Bioassay sampling was 

stopped by 1961 for mostly economic reasons and because it was thought that exposure levels 

had been established. Bioassay sampling was restarted in December of 1962, when it turned out 

that some workers had significant intakes of radioactive material. To do dose reconstruction for 

1961 and 1962, NIOSH relies on extrapolated urine bioassay information from years prior to 

1961 (see Battelle TBD-6001, Appendix D) with the assumption that the this is a claimant 

friendly approach as opposed to using the available air sampling data for this period. During 

work group discussions SC&A has raised doubt that the air sample data from 1961-1962 support 

the approach used by NIOSH. 

The following paper shows: 

1) Air sample data is available through the entire “gap period” from January 1961 through 

December of 1962. 

2) Air sample data largely correlates with the activities at the plant (i.e. exposure heavy 

activities were monitored) 

3) Intakes calculated from bioassay are more claimant friendly than intakes derived from air 

data 

1. Available air sample data for 1961 and 1962 

Air sample data from 1961 and 1962 are available for various operations, persons and areas, 

including the operations that caused the highest exposure in the workers when bioassay samples 

were collected (the highly enriched uranium work in the Red Room). Table 1 gives an overview 

of the available data. 

1961: 

•	 310 air samples (GA/BZ/SS), results available for every month of the year for 1961, 

except December. Locations, dates and type of sample are noted on the sample sheets. 

•	 Summary report of worker exposures to air contamination for 132 workers, no work 

locations are indicated, (Ref ID: 062179). 

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1962:
 

•	 171 (GA/BZ/SS) air samples, results are available for every month of the year except 

December. Locations, dates and type of sample are noted on the sample sheets. 

•	 Two sets of personal exposure records containing worker specific air sample data from 

April to December and July to December of 1962 respectively (total of 58 data points), 

(Ref ID: 062172). 

•	 Results of a specific “dust study” from the Pellet Plant in February of 1962 (a total of 58 

data points were collected, but the report only contains averages, minimum and 

maximum values), (Ref ID: 062306) 

•	 Integrated dust exposure results for workers. Dates range from January 1962 through 

December 1962 and represent weekly dust exposure results for individual workers in 

μCi/ml of alpha activity. Each result sheet has data for about 90 workers each week 

totaling to 1787 data points, representing 20 weekly periods in 1962 (Ref ID 062179). No 

sample locations available, although some high readings indicate type of work or location 

by handwritten note. 

Locations:
 

General Air, Breathing Zone and Source Sample air samples were collected in the following
 

locations:
 

o	 Red room, at various operations and locations (Ref ID: 062276) 

o	 Green room, various locations and operations (Ref ID: 062283) 

o	 Blue Room, various locations and operation (Ref ID: 062328, 062340) 

o	 Item 1 plant various locations (Ref ID: 062285) 

o	 Pellet Plant, various locations (Ref ID: 062285, 062328, 062287) 

o	 Laundry area (Ref ID: 062171) 

o	 Warehouse area (Armco warehouse), various locations (Ref ID: 062171) 

o	 Blender room, various locations (Ref ID: 062282) 

o	 Guard Station (Ref ID: 062171) 

o	 Office area (Ref ID: 062171) 

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Table 1. Air sample data points available for each location
 

1961 # data 1962 # data Illegible date 

Location points points (but likely ’61 

or ’62) 

Red Room 104 21 15 

Green Room 36 4 

Blue Room 73 93 

Blender Room 3 4 

Item #1 plant 29 7 

Pellet Plant 41 95 

Armco Warehouse 14 0 

Guard Station 0 3 

Office 0 3 

Laundry 5 0 

Unknown area 5 0 

Integrated personal dust 132* 1847* 

exposure 

Total 442 2077 15 

* These are reported as personal exposure results in μCi/ml. It is not clear how they were 

calculated; I assume that they may have been derived from GA or BZ samples in the workers’ 

area. 

2. Air sample data correlate with the activities at the plant (i.e. exposure heavy activities 

were monitored) 

The following section focuses on the available general air, breathing zone and source sample 

data sets and do not include the integrated personal exposure data, since those do not include 

location information. 

The Red Room was the area where operations with highly enriched uranium took place, and 

where high worker exposures were measured when in 1962. It was determined that workers were 

acquiring large amounts of contamination on their hands from handling uranium without gloves 

(Ref ID 011724, page 54, Ref ID 062316, pg. 2). During the time period when no bioassay 

sampling took place, the Red Room was the location where many air samples were collected. 

After the bioassay sampling was reinstated in 1962, it was found that a few of the Red Room 

workers had received some significant intakes, so it is reasonable to assume that the Red Room 

operations were the ones with the highest exposure potential for the workers. 

The Administrative Control Level (ACL) for alpha radioactivity in air during the 1961-1962 

period was 110 dpm/m3 for operations involving “normal” uranium (up to 2 % enriched) and 220 

dpm/m3 for uranium enriched > 2 % (Ref ID 062306). Table 2 lists the air concentration results 

above 220 dpm/m3

. Of the 37 measurements that were above the ACL of 220 dpm/m3, ten (27 

%) were measured in the Red Room and an additional 14 were measured in other areas where 

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enriched (> 2 %) uranium was handled (Blue Room, Item Plant, Pellet Plant, Green Room). This 

number could be misleading, since the sample sheets don’t always mention the enrichment factor 

of the material being handled. Additional locations were the ACL was exceeded were the 

Blender Room, the Pellet Plant and the Laundry Area, where presumably contaminated clothing 

was handled and washed. The highest sample of 35520 dpm/m3 is from an unknown location 

(Illegible entry) and has an explanation written on the data sheet, which is also illegible. 

Table 2. Locations and air concentration values above ACL for enriched uranium
 

Sample 

Number 

Sample 

Date 

SRDB 

Ref 

ID 

Location/activity Result 

(dpm/m3

) 

95 2/17/1961 62171 unknown, some operation, BZ 35520 

85 4/4/1962 62340 Blue Room, Wet Bay operations, 2.2 %, BZ 27600 

84 4/4/1962 62340 Blue Room, hydrolysis operations, BZ 10307 

52 1/26/1961 62283 Green Room, misc. ops, BZ 1043 

47 1/11/1961 62340 Blue Room, Recovery ops 3.5, BZ 1013 

206 3/31/1961 62328 BZ 93 % shot, Blue Room R&D, BZ 952 

205 3/31/1961 62328 BZ 93 % shot, Blue Room R&D, BZ 938 

96 2/17/1961 62171 unknown, some operation, GA 910 

160 6/26/1962 62276 Red Room, at UF6 conversion hood, GA 906 

? 1/11/1961 62340 Blue Room, Recovery ops 3.5, BZ 875 

Red Room during demolition of hydrolysis 

370 7/31/1961 62276 hood, cont. on floor, 12'' west of hood, GA 686 

Red Room during demolition of hydrolysis 

371 7/31/1961 62276 hood, mill and sift hood, GA 635 

80 4/4/1962 62340 Blue Room, Wet Bay operations, 2.2 %, BZ 578 

81 4/4/1962 62340 Blue Room, hydrolysis operations, BZ 517 

Blue Room, GA at side Bink's hood, R&D 

1 1/9/1962 62328 annex, GA 515 

Laundry operations, sorting clothes in washer, 

162 3/22/1961 62171 BZ 480 

133 5/9/1962 62276 Red Room, UF4 ops, unloading ? Reactor, GA 444 

51 1/26/1961 62283 Green Room, misc. ops, BZ 422 

29 1/13/1961 62283 Green Room, 4.8 %, GA 400 

232 4/19/1961 62276 Red Room , direct green, 93 % UF6/UF4, BZ 319 

Red Room during demolition of hydrolysis 

372 7/31/1961 62276 hood, cont. on floor, 12'' west of hood, GA 311 

49 1/23/1961 62340 Blue Room, Recovery ops 3.05, BZ 305 

345 6/22/1961 62276 Red Room, 93 % operations, UF4..., GA 300 

23 2/13/1962 62287 over outlet [...] vac. Cleaner, SS 295 

S. Bay pellet plant, welding area top of large 

59 2/6/1961 62171 reactor, GA 289 

Red Room, processing 93% material, Station 2 

278 5/23/1961 62276 in front of pyro furnaces, GA 280 

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SRDB Sample 

Number 

Sample 

Date Ref 

ID 

Location/activity Result 

(dpm/m3) 

59 2/2/1961 62282 Blender Room, using U3O8 (3.05), BZ 266 

455 10/5/1961 62285 Item #1 plant, using 93 % feed, GA/BZ 266 

456 10/5/1961 62285 Item #1 plant, using 93 % feed, GA/BZ 266 

169 (?) 5/10/1962 62282 Blender Room, 3.0 %, BZ 266 

Red Room during demolition of hydrolysis 

373 7/31/1961 62276 hood, mill and sift hood, GA 262 

39 2/16/1962 62287 PP, grinding 2.4 % pellets, BZ 254 

459 10/5/1961 62285 Item #1 plant, using 93 % feed, GA/BZ 244 

163 3/22/1961 62171 Laundry operations, wet clothing bin, GA 225 

3 10/19/1962 62287 PP, while putting in new press, 224 

460 10/5/1961 62285 Item #1 plant, using 93 % feed, GA/BZ 222 

Red Room, processing 93% material, Station 2 

281 5/23/1961 62276 in front of pyro furnaces, GA 222 

3. Intakes calculated from bioassay are more claimant friendly than intakes derived from 

air data 

The available air sample data sets from 1961 and 1962 were fit to a lognormal distribution and 

the geometric mean (GM) and geometric standard deviation (GSD) were derived from the data. 

Separate analyses were done for the GA/BZ/SS data set and the integrated personal exposure 

data set. A separate analysis was also done using data for only the Red Room. The entire data 

set has a GM of 20.3 dpm/m3 and a GSD of 4.8. The data only for the Red Room has a GM of 

32.2 dpm/m3 and a GSD of 3.4. Using the 1961 and 1962 worker exposures air date (Ref ID 

062179), the GM is 35.8 dpm/m3 and the GSD is 2. 

Potential worker intakes were calculated by using the GM values and assuming a daily inhalation 

rate of 9.6 m3

/d (assumes an 8 hour workday). The table below lists the daily intake values 

derived from the air sample data as well as the intake data derived from Battelle TBD-6001, 

Appendix D, which is what is currently used for dose reconstructions. 

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Table 3. Comparison of derived intake values from air concentration data vs. bioassay data
 

Data Set N (# data 

points) 

GM (GSD) daily 

intake from air 

sample (dpm/d) 

95th percentile, 

daily intake 

from air sample 

(dpm/d) 

TBD-6001 App.D 

intake (dpm/d)a) 

All locations 491 195 (4.8) 2555 Operators: 

12590 (Type S) 

871.9 (Type M) 

Red Room only 243 309 (3.4) 2304 

Supervisors/Other 

Worker data 1921 344 (2.0) 1034 4784 (Type S) 

331.2 (Type M) 

a) See Battelle-TBD-6001; Appendix D, Table D.1, intake values represent the GM of a 

lognormal distribution derived from bioassay results. 

Table 3 shows that the intakes derived from the air data collected during 1961 and 1962 are 

much lower that the intakes derived from the urine bioassay from years prior to 1961 and that the 

intakes presented in the current TBD are bounding when compared to the air sample data. 

References 

Air Sample Data, 1961, Air Sample Data Sheet –United Nuclear Corporation; AEC Health and 

Safety Laboratory; August 1961; SRDB Ref ID: 7105 

Air Sample Data, 1961-63, Air Sample Data Sheet –United Nuclear Corporation; Mallinckrodt 

Chemical Works; various dates in 1961-63; SRDB Ref ID: 62285 

Air Sample Data, 1961-63, Air Sample Data Sheet –United Nuclear Corporation; Mallinckrodt 

Chemical Works; various dates in 1961-63; SRDB Ref ID: 62285 

Assorted Results, 1963, Assorted Air and Contamination Study Results, United Nuclear Corporation; 

various dates in 1963; SRDB Ref ID: 62276 

Battelle-TBD-6001, Appendix D, Site Profiles for Atomic Weapons Employers that Refined Uranium 

and Thorium—Appendix D United Nuclear Corp., Rev. 0; Battelle; March 14, 2008; SRDB Ref ID: 

Blending Room, 1961-63, Blending Room Air Sample Data, United Nuclear Corporation; various 

dates in 1961-1963; SRDB Ref ID: 62282 

Blue Room, 1960-63, Various Air Sample Data Sheets, Mallinckrodt Chemical Works; various dates 

1960-1963; SRDB Ref ID: 62328 

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Blue Room, 1962-63, Various Air Sample Data Sheets, Mallinckrodt Chemical Works; various dates 

1962-1963; SRDB Ref ID: 62340 

Dust Exposure, 1962, United Nuclear Corporation Integrated Dust Exposure, United Nuclear 

Corporation; various dates in 1962; SRDB Ref ID: 62179, pdf pp. 7-54 

Estimated Exposures, 1963, Estimated Lung Exposures for Entire Year, 1963, letter from J. A. 

Lindberg (V.P., UNC) to C. Keller (AEC); United Nuclear Corporation; October 28, 1963; SRDB 

Ref ID: 62316 

Green Room, 1961-63, Green Room Air Sample Data, Mallinckrodt Chemical Works; various dates 

in 1961-63; SRDB Ref ID: 62283 

Non-process Air Samples, 1961-63, Lunchroom, Armco Warehouse, and Other Locations Air 

Samples, United Nuclear Corporation; various dates in 1961-1963; SRDB Ref ID: 62171 

Pellet Plant, 1961-62, Pellet Plant Air Sample Data, Hematite, Mo., Mallinckrodt Chemical Works; 

various dates in 1961-62; SRDB Ref ID: 62287 

Pellet Plant, 1961-62, Pellet Plant Air Sample Data, Hematite, Mo., Mallinckrodt Chemical Works; 

various dates in 1961-62; SRDB Ref ID: 62287 

Uranium Dust, 1962, Uranium Dust Study of Pellet Plant Operations – Bldg. 255-2, United Nuclear 

Corporation; October 1962; SRDB Ref ID: 62306 

Various authors, 1963, UNC Bioassay Program Information and Some Results for 4-19-63 to 11-4­

63; various authors; SRDB Ref ID: 11724 

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