Draft Memo – Hooker Surrogate Data 1 SC&A – September 22, 2011 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

 

DRAFT MEMO 

TO: Uranium Refining Atomic Weapons Employers (AWEs) Work Group 

FROM: W.C. Thurber, SC&A 

DATE: September 22, 2011 

SUBJECT: Use of Surrogate Air Sampling Data at Hooker Electrochemical Company: 

Comparison of DCAS and SC&A Approaches 

At the August 2011 meeting of the ABRWH, the Board requested that additional information be 

provided comparing the differences in the air sampling data sets used by the Division of 

Compensation Analysis and Support (DCAS) and SC&A to characterize internal exposures for 

workers at the Hooker Electrochemical Company (Hooker). This memorandum provides the 

requested comparison. 

From July 11, 1944, through January 15, 1946, Hooker processed C-2 slag (basically MgF2 and 

CaO) generated during the exothermic bomb reduction of UF4 with Mg. The process at Hooker 

involved leaching of the slag with HCl to remove some of the slag constituents and increase the 

uranium content. The Hooker process was described at the time of AWE operations as follows 

(MED 1944): 

Slag is received in barrels containing about 500 lbs. The barrels are opened and the 

material is dumped on a conveyor belt which carries it up a ramp to one of the three 

digest tanks. [The as-received material was passed over a 20-mesh screen and 

only the undersize was conveyed to the digester tanks. The oversize was redrummed and shipped off-site.]1

 40 barrels are added to each tank. Waste HCl 

from the P-45 plant is passed into the digest tank and the pH is adjusted to 4.0 by the 

addition of water. After the tank has been filled, the contents are agitated for 

20 hours. About once in two days a tank is emptied, which is sufficient turn-over to 

take care of waste HCl. At the completion of the digest the slurry is neutralized by 

dumping 100-lb. bags of lime into the tanks from an overhead platform, pumped to a 

plate and frame press, and filtered. The filtrate is passed off into the sewer; the 

precipitate is washed several times and rebarreled. Slag is concentrated from about 

1 lb. [of uranium] to 5 or 10 lbs. [of uranium] by weight. 

Since no monitoring data were available at Hooker to characterize internal exposures, DCAS 

relied on surrogate data. In selecting the surrogate data for estimating internal exposure of AWE 

workers at Hooker, DCAS determined that relevant air sampling data were available from 

Fernald, Mallinckrodt (MCW) and ElectroMet that could be used to construct doses at Hooker. 

From the available literature sources, DCAS selected 18 measurements which, in their technical 

judgment, could be used for dose reconstruction. These data are summarized in Table 1 (DCAS 

2011, Table 1). 

1

 Bracketed comment added by SC&A. 
Draft Memo – Hooker Surrogate Data 2 SC&A – September 22, 2011 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

Table 1. Magnesium Fluoride Air Samples 

Site Task 

Air 

Concentration 

(dpm/m3

) 

Comments SRDB 

reference 

ElectroMet Loading slag into barrels and 

weighing 

456 Average of unknown 

number of samples 

8917 pg. 7 

ElectroMet Shoveling slag into drums 398 Average of three 8930 pg. 19 

Mallinckrodt Slag Man 154 9340 pg. 4 

Mallinckrodt Slag handling 154 11553 

Mallinckrodt Slag Man 77 9341 pg. 5 

Mallinckrodt Removing slag drum 237 9443 pg. 19 

Mallinckrodt Removing slag drum 60.8 9443 pg. 19 

Fernald BZ – dumping can of C-liner 247 34544 

Fernald BZ – dumping can of C-liner 191 34544 

Fernald BZ – dumping can of C-liner 255 34544 

Fernald BZ – dumping can of C-liner 206 34544 

Fernald BZ – dumping drum of C-liner 793 42627 

Fernald BZ – dumping drum of C-liner 829 42627 

Fernald BZ – dumping drum of C-liner 424 42627 

Fernald BZ – dumping drum of slag 

outdoors 

32 42628 

Fernald BZ – dumping drum of slag 

outdoors 

110 42628 

Fernald BZ – dumping drum of slag 

outdoors 

85 Value calculated from 

average, min and max 

42628 

Fernald BZ – dumping drum of slag 

outdoors 

85 Value calculated from 

average, min and max 

42628 

It should be noted that a majority of the samples in Table 1 were breathing zone (BZ) samples 

from Fernald. From this sample set, DCAS determined that the 95th percentile was 806 dpm/m3

and used that datum as one piece of the information required to estimate internal exposures. 

SC&A reviewed the data set in Table 1 and provides the following observations: 

 The MCW tasks Slag Man and Slag Handling as described in the SRDB references are 

for an operator grinding C-Special slag. We presume that this refers to the process of 

grinding adhering slag from the uranium derbies, rather than grinding slag for particle 

size reduction. In either case, these operations do not seem consistent with the process 

description for Hooker. 

 

 If these tasks were eliminated from Table 1, the impact on the 95th percentile would be 

small, increasing its value from 806 dpm/m3

 to 966 dpm/m3. 

SC&A developed its air sampling data set based primarily on the same references by applying 

technical judgment as to which samples should be included and which should be excluded. 

SC&A recognizes that such judgments carry a significant degree of subjectivity. At the time 

SC&A prepared its review of the use of surrogate data at Hooker, we used a data set of 67 

samples (SC&A 2011) and determined that the 95th percentile of the slag-handling air samples 
Draft Memo – Hooker Surrogate Data 3 SC&A – September 22, 2011 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

was 555 dpm/m3. In addition to the Fernald samples included in the DCAS data set (Table 1), 

SC&A included data from three other Fernald operations described in SRDB 42628: 

 “Laborer used push broom to clean loose material from floor of gondola. Material dry 

and very dusty. No respirator worn.” SC&A felt that this would be akin to sweeping up 

any spilled slag at the unloading dock at Hooker. 

 “Laborer inside gondola with hatchet and shovel. Man cuts and shovels material from 

side of gondola and pitches onto pile on pad.” SC&A felt that similar measures might be 

required at Hooker to remove any caked product from the wooden shipping barrels. 

 “Hand shoveling airport scrap into 30-gal containers on outside pad. No visible dust. No 

respirator worn.” SC&A felt that this activity was similar to reloading of oversized slag 

that was not processed, but re-barreled and shipped off-site. 

SC&A also included four BZ samples from MCW for a task described as “changing slag drums” 

(SRDB 20657). 

SC&A subsequently added three samples from Fernald that were uncovered during a September 

2011 update of a previously reviewed reference (NLO 1959). The operation was described as 

“Operator dumping 55-gal drum of MgF2 into leach tank, taking drum off and relidding drum,” 

and BZ exposures ranged from 1,125 to 1,674 dpm/m3

. It is reasonable that similar exposures 

could have been incurred when slag was transferred to the digester tanks at Hooker. 

A detailed comparison of the DCAS sample set and the SC&A sample set is provided in Table 2. 

As noted previously, DCAS had determined that the 95th percentile for the Table 1 sample set 

was 806 dpm/m3

, while the 95th percentile value for the larger SC&A sample set (revised to 

September 2011) was 759 dpm/m3, indicating that the 95th percentile is not particularly sensitive 

to reasonable but differing technical judgments in sample selection. 

Table 2. Summary of Air Sampling Results from Slag Handling at Fernald, 

ElectroMet and MCW 

Site Sample 

No. 

Dust 

Count 

(dpm/m3

) 

Type of 

Sample 

Sample 

Location Job Description 

Included 

in NIOSH 

Analysis? 

Included 

in SC&A 

Analysis? 

SRDB 

Reference 

Fernald 1639 198 BZ Outside Laborer used push 

broom to clean loose 

material from floor of 

gondola. Material dry 

and very dusty. No 

respirator worn. 

No Yes 42628, pg. 13 

Fernald 1640 232 BZ Outside Ditto No Yes 

Fernald 1641 233 BZ Outside Ditto No Yes 

Fernald 1642 490 BZ Outside Ditto No Yes 

Fernald 1643 257 BZ Outside Ditto No Yes 

Fernald 1644 346 BZ Outside Ditto No Yes 
Draft Memo – Hooker Surrogate Data 4 SC&A – September 22, 2011 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

Table 2. Summary of Air Sampling Results from Slag Handling at Fernald, 

ElectroMet and MCW 

Site Sample 

No. 

Dust 

Count 

(dpm/m3

) 

Type of 

Sample 

Sample 

Location Job Description 

Included 

in NIOSH 

Analysis? 

Included 

in SC&A 

Analysis? 

SRDB 

Reference 

Fernald 1645 261 BZ Outside Ditto No Yes 

Fernald 1646 200 BZ Outside Ditto No Yes 

Fernald 1647 627 BZ Outside Ditto No Yes 

Fernald 1648 336 BZ Outside Ditto No Yes 

Fernald 1649 195 BZ Outside Ditto No Yes 

Fernald 1650 338 BZ Outside Ditto No Yes 

Fernald 1105 15 BZ Outside Laborer inside gondola 

with hatchet and 

shovel. Man cuts and 

shovels material from 

side of gondola and 

pitches onto pile on 

pad. 

No Yes 42628, pg. 14 

Fernald 1106 15 BZ Outside Ditto No Yes 

Fernald 1107 30 BZ Outside Ditto No Yes 

Fernald 1108 37 BZ Outside Ditto No Yes 

Fernald 1109 97 BZ Outside Ditto No Yes 

Fernald 1110 162 BZ Outside Ditto No Yes 

Fernald 1111 7 BZ Outside Ditto No Yes 

Fernald 1112 69 BZ Outside Ditto No Yes 

Fernald 1113 15 BZ Outside Ditto No Yes 

Fernald 1114 47 BZ Outside Ditto No Yes 

Fernald 1115 32 BZ Outside Ditto No Yes 

Fernald 1116 83 BZ Outside Ditto No Yes 

Fernald 1117 80 BZ Outside Ditto No Yes 

Fernald 1118 68 BZ Outside Ditto No Yes 

Fernald 1119 36 BZ Outside Ditto No Yes 

Fernald 1120 135 BZ Outside Ditto No Yes 

Fernald 1121 181 BZ Outside Ditto No Yes 

Fernald 1122 32 BZ Outside Ditto No Yes 

Fernald 1123 83 BZ Outside Ditto No Yes 

Fernald 1124 64 BZ Outside Ditto No Yes 

Fernald 1125 30 BZ Outside Ditto No Yes 

Fernald 1126 23 BZ Outside Ditto No Yes 

Fernald 1127 53 BZ Outside Ditto No Yes 

Fernald 1128 79 BZ Outside Ditto No Yes 

Fernald 1129 34 BZ Outside Ditto No Yes 

Fernald 1130 45 BZ Outside Ditto No Yes 

Fernald 1131 106 BZ Outside Hand shoveling airport 

scrap into 30-gal 

containers on outside 

pad. No visible dust. 

No respirator worn. 

No Yes 42628, pg. 16 
Draft Memo – Hooker Surrogate Data 5 SC&A – September 22, 2011 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

Table 2. Summary of Air Sampling Results from Slag Handling at Fernald, 

ElectroMet and MCW 

Site Sample 

No. 

Dust 

Count 

(dpm/m3

) 

Type of 

Sample 

Sample 

Location Job Description 

Included 

in NIOSH 

Analysis? 

Included 

in SC&A 

Analysis? 

SRDB 

Reference 

Fernald 1132 91 BZ Outside Ditto No Yes 

Fernald 1133 75 BZ Outside Ditto No Yes 

Fernald 1134 38 BZ Outside Ditto No Yes 

Fernald 1135 7 BZ Outside Ditto No Yes 

Fernald 1136 19 BZ Outside Ditto No Yes 

Fernald 1137 95 BZ Outside Ditto No Yes 

Fernald 1138 75 BZ Outside Ditto No Yes 

Fernald 1139 49 BZ Outside Ditto No Yes 

Fernald 1140 45 BZ Outside Ditto No Yes 

Fernald 1141 30 BZ Outside Ditto No Yes 

Fernald 1142 19 BZ Outside Ditto No Yes 

Fernald 3556 110 BZ Outside Operator dumping 

drum of slag liner into 

outside crusher 

dumping station. No 

respirator worn, 

Ventilation appears to 

be very effective. 

Yes Yes 42628, pg. 90 

Fernald 3472 108 BZ Outside Ditto Yes Yes 

Fernald 3558 61 BZ Outside Ditto Yes Yes 

Fernald 3557 32 BZ Outside Ditto Yes Yes 

Fernald 6993 793 BZ inside Operator dumping 

drum of C-liner from 

2nd floor drum dumper

Yes Yes 42627, pg. 61 

Fernald 7509 829 BZ inside Ditto Yes Yes 

Fernald 7302 424 BZ inside Ditto Yes Yes 

Fernald 626 247 BZ inside BZ dumping can of 

C-liner into dumping 

station. Respirator 

worn 

Yes Yes 34544, pg. 2 

Fernald 623 191 BZ inside Ditto Yes Yes 

Fernald 736 255 BZ inside Ditto Yes Yes 

Fernald T899 206 BZ inside Ditto Yes Yes 

ElectroMet III. 2 & 6 456 BZ?? inside Bomb Room, barrel 

slag and weigh 

Yes Yes 8917, pg. 7 

ElectroMet N/A 398 BZ?? inside Shovels slag into lean 

and rich drums 

Yes Yes 8930, pg. 19 

MCW Nov-53 107 BZ inside Breakout man changing 

C-oxide and slag liner 

drums 

No Yes 20657, pp. 11 

and 23 

MCW Nov-53 7 BZ inside Ditto No Yes 

MCW Apr-53 81 BZ inside Ditto No Yes 

MCW Oct-52 27 BZ inside Ditto No Yes 

MCW A 237 BZ inside Bomb unloaders Yes Yes 9343, pg. 19 
Draft Memo – Hooker Surrogate Data 6 SC&A – September 22, 2011 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

Table 2. Summary of Air Sampling Results from Slag Handling at Fernald, 

ElectroMet and MCW 

Site Sample 

No. 

Dust 

Count 

(dpm/m3

) 

Type of 

Sample 

Sample 

Location Job Description 

Included 

in NIOSH 

Analysis? 

Included 

in SC&A 

Analysis? 

SRDB 

Reference 

removing C-special 

drum 

MCW B 60.8 BZ inside Ditto Yes Yes 

MCW 1948 154 DWA inside Slag Man grinding 

C-special 

Yes No 9340, pp. 4, 

16, and 50 

MCW 1949 79 DWA inside Ditto Yes No 

MCW 1950 79 DWA inside Ditto No No 9341, pp. 6 

and 38 

MCW 154 DWA inside Ditto (duplicate of 

MCW 1948) 

Yes No 11553, pp. 6 

and 53 

Fernald 4906 1125 BZ inside Operator dumping 

55-gal drum of MgF2

into leach tank, taking 

drum off and relidding 

drum. 

No Yes 42628, pg. 93 

Fernald 4907 1674 BZ inside Ditto No Yes 

Fernald 4908 1533 BZ inside Ditto No Yes 

References 

Brealia, A.J. 1949. Electro Metallurgical Co. Occupational Exposure to Radioactive Dust 

August 17-19, 1949; November 10, 1949. SRDB Ref ID: 8930. 

Caplan, K.J. 1949. From K.J. Caplan (MCW) to Thayer (AEC), Subject: Dust Study at MCW 

Plant 4. February 2, 2949. SRDB Ref ID: 11553. 

Caplan, K.J. 1951. From K.J. Caplan (MCW) to Thayer (AEC), Subject: Results of Dust Study 

Six-E. February 26, 1951. SRDB Ref ID: 9343. 

DCAS 2011. Technical Basis Document for Hooker Electrochemical Company, Niagara Falls 

NY. DCAS-TKBS-0009. Revision 1. 6/17/2011. 

Huelston, D.J. 1950a. From D.J. Huelston (MCW) to K.J. Caplan (MCW), Subject: 

Mallinckrodt Chemical Works Plant Four Dust Study. March 1, 1950. SRDB Ref ID: 9340. 

Huelston, D.J. 1950b. From D.J. Huelston (MCW) to K.J. Caplan and Mason (MCW), Subject: 

Mallinckrodt Chemical Works Plant Four Dust Study Recheck. June 1, 1950. SRDB Ref ID: 

9341. 
Draft Memo – Hooker Surrogate Data 7 SC&A – September 22, 2011 

 This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

NOTICE:

MCW no date: MCW Plant 6E, Occupational Exposure to Airborne Contaminants, MCW-18. 

References a study done November 18–20, 1953. Mallinckrodt Chemical Works, Industrial 

Hygiene Branch, Health and Safety. SRDB Ref ID: 20657.

MED 1944. Medical Section – Manhattan District, Data Sheets for Industrial Hazard Rating. 

Manhattan Engineer District. SRDB Ref ID: 16323, pp. 29–30. 

NLO 1956. Analytical Data Sheet Plant 8, BZ Results. Fernald. National Lead of Ohio. SRDB 

Ref ID: 34544. 

NLO 1958. Plant 8 Analytical Data Sheet, Air Dust, 1957–1970. Fernald. National Lead of 

Ohio. March 7 to October 13, 1958. SRDB Ref ID: 42627. 

NLO 1959. Plant 8 Analytical Data Sheet, Air Dust, 1957–1970. Fernald. National Lead of 

Ohio. February 6 to December 24, 1959. SRDB Ref ID: 42628. 

SC&A 2011. SC&A Review of NIOSH White Paper, “Surrogate Data Evaluation – Hooker 

Electrochemical Company.” Contract No. 200-2009-28555. July 7, 2011. 

Various, 1947–1948. Reports on Dust Hazards at Electrometallurgical Company; various 

authors; dates from December 1947 through May 1948; SRDB Ref ID: 8917.