Division of Compensation Analysis and Support

Technical Basis Document for the Hooker Electrochemical

Company

Niagara Falls, New York 

Document Number:

DCAS-TKBS-0009

Effective Date: 06/17/2011

Revision No.: 1

Page 1 of 16

Subject Expert: David Allen

Approval: Signature on file Date: 06/17/2011

Supersedes:

DCAS-TKBS-0009

James W. Neton, Associate Director for Science Rev. 0

TABLE OF CONTENTS 

Section Page

1.0 Introduction .................................................................................................................................. 4

2.0 Site Description and Operational History ..................................................................................... 5

3.0 Process Description ...................................................................................................................... 6

3.1 Uranium Concentration ...........................................................................................................6

3.2 Monthly Production Rate ........................................................................................................7

3.3 Daily Production Rate .............................................................................................................8

4.0 Internal Dose ................................................................................................................................. 8

5.0 External Dose ............................................................................................................................. 10

5.1 Slag Barrel ............................................................................................................................. 11

5.2 Concentrate Barrel ................................................................................................................ 11

5.3 External Dose from Surface Contamination ......................................................................... 12

5.4 External Dose Summary........................................................................................................ 12

6.0 Residual Contamination ............................................................................................................. 13

7.0 Occupational Medical Dose ........................................................................................................ 14

8.0 References .................................................................................................................................. 15

LIST OF TABLES 

Table Page

Table 1: Magnesium Fluoride Air Samples .................................................................................................. 9

Table 2: Slag Barrel External Dose Rates ................................................................................................... 11

Table 3: Concentrate External Dose Rates ................................................................................................. 12

Table 4: Surface Contamination External Dose Rates ................................................................................ 12

Table 5: External Dose Summary ............................................................................................................... 13

Table 6: Residual Period Dose Summary ................................................................................................... 14
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LIST OF FIGURES 

Figure Page

Figure 1: Air Sample Distribution .............................................................................................................. 10
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RECORD OF ISSUE/REVISIONS 

ISSUE

AUTHORIZATION

DATE

EFFECTIVE

DATE REV. NO. DESCRIPTION

4/4/2011 4/4/2011 0 Changes Battelle-TBD-6001 Appendix to 

a standalone document. Revises dose 

models to eliminate dependence on 

Battelle-TBD-6001. Provides more 

detailed description of dose models. 

Incorporate review comments.

06/16/2011 06/17/2011 1 Revision initiated to correct errors in 

Tables 2, 3, and 6. Renumber tables after 

Table 4. Added language on page 10 to 

indicate the 95th percentile of the airborne 

values was used. Corrected 

typographical error on page 7 and 14. 
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1.0 Introduction

Technical basis documents and site profile documents are not official determinations made by 

the National Institute for Occupational Safety and Health (NIOSH) but are rather general 

working documents that provide historic background information and guidance to assist in the 

preparation of dose reconstructions at particular sites or categories of sites. They will be revised 

in the event additional relevant information is obtained about the affected site(s). These 

documents may be used to assist NIOSH staff in the completion of the individual work required 

for each dose reconstruction. 

In this document the word “facility” is used as a general term for an area, building, or group of 

buildings that served a specific purpose at a site. It does not necessarily connote an “atomic 

weapons employer [AWE] facility” or a “Department of Energy [DOE] facility” as defined in the 

Energy Employees Occupational Illness Compensation Program Act of 2000 [EEOICPA; 42 

U.S.C. § 7384I(5) and (12)]. EEOICPA, as amended, provides for employees who worked at an 

AWE facility during the contract period and/or during the residual period. 

Under EEOICPA, employment at an AWE facility is categorized as either (1) during the DOE 

contract period (i.e., when the AWE was processing or producing material that emitted radiation 

and was used in the production of an atomic weapon), or (2) during the residual contamination 

period (i.e., periods that NIOSH has determined there is the potential for significant residual 

contamination after the period in which weapons-related production occurred). For contract 

period employment, all occupationally derived radiation exposures received at covered facilities 

must be included in dose reconstructions. This includes radiation exposure related to the Naval 

Nuclear Propulsion Program and any radiation exposure received from the production of 

commercial radioactive products that were concurrently manufactured by the AWE facility 

during the covered period. NIOSH does not consider the following exposures to be 

occupationally derived (NIOSH 2010):

Background radiation, including radiation from naturally occurring radon present in 

conventional structures 

Radiation from X-rays received in the diagnosis of injuries or illnesses or for therapeutic 

reasons 

For employment during the residual contamination period, only the radiation exposures defined 

in 42 U.S.C. § 7384n(c)(4) [i.e., radiation doses received from DOE-related work] must be 

included in dose reconstructions. Doses from medical X-rays are not reconstructed during the 

residual contamination period (NIOSH 2007). It should be noted that under subparagraph A of 

42 U.S.C. § 7384n(c)(4), radiation associated with the Naval Nuclear Propulsion Program is 

specifically excluded from the employee’s radiation dose. This exclusion only applies to those 

AWE employees who worked during the residual contamination period. Also, under 

subparagraph B of 42 U.S.C. § 7384n(c)(4), radiation from a source not covered by subparagraph 

A that is not distinguishable through reliable documentation from radiation that is covered by 

subparagraph A is considered part of the employee’s radiation dose. This site profile covers only 

exposures resulting from nuclear weapons-related work. Exposures resulting from nonweapons-related work, if applicable, will be covered elsewhere. 
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The following information from the Department of Energy’s Office of Health, Safety and 

Security EEOICPA Find Facilities webpage defines the EEOICPA covered periods for the 

Hooker Electrochemical Company. 

Site: Hooker Electrochemical Company 

Location: Niagara Falls, New York 

Covered Period: 1943-1948, Residual Radiation 1949-1976

This document contains a summary of the description of the site as well as the Atomic Energy 

Commission activities performed there, and provides the technical basis to be used to evaluate 

the occupational radiation doses for EEOICPA claims. 

2.0 Site Description and Operational History

The Hooker Electrochemical Company (HEC) was located in Niagara Falls, New York. From 

January, 1943 until June, 1948 under contract No W-7405 eng-28 with the Manhattan 

Engineering District (MED), HEC manufactured various organic chemicals including xylene 

hexafluoride (P-45), xylene hexachloride, and Miller’s Fluoro Lubricant (MFL). While these 

processes in themselves did not involve radioactive materials, during part of this period, 

hydrochloric acid, a byproduct of the P-45 process, was used to chemically treat uranium bearing 

C-2 slag as a precursor to uranium recovery (DOE 1985, pg 58). 

The HEC site used under the MED program was the “D” area, 5.5 acres located on the north 

bank of the Niagara River in Niagara Falls, NY, about 2 miles east of the falls. Five buildings on 

this site, D-5, 6, 7, 8 and 9 were used under the contract with MED (1943-48). The bulk of 

uranium handling was conducted outdoors in an area by the railroad siding north of these 

buildings. This activity involved the chemical processing of uranium-bearing slag for recovery 

purposes (DOE 1985, Olotka 1979). 

The covered period for Hooker Electrochemical is listed by the Department of Energy’s Office 

of Worker Advocacy as 1943 through 1948 and includes both radioactive material processing 

and nonradioactive chemical production activities for the Manhattan Engineer District (MED) 

(DOE 2009). The only weapons-related radiation exposure occurred while processing uranium 

contaminated slag for MED. A 49’ x 28’ x 25’ cinder block building to contain some of the 

necessary equipment was constructed under a letter of intent dated May 1944. Construction was 

completed and the building turned over to the Operating Department on July 11 1944 (Dowling 

1944). No documentation was found indicating there were other sources of radiation, 

commercial or weapons-related, at Hooker Electrochemical. 

A process description indicates this process was sufficient to take care of the excess HCl from 

the P-45 process (MED 1944). The P-45 process ended on January 15, 1946 (Mears 1946). This 

document establishes the period of operational radiation exposure from July 11, 1944 to January 

15, 1946. It is possible that the slag-processing occurred for an even shorter period since some 

start up period would be expected. This analysis assumes a period of residual radioactivity 

exposure from January 16, 1946 to October 11, 1976, the date when measurements for radiation 
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and radioactivity onsite were made and it was concluded that no elevated levels of radioactivity 

were onsite (DOE 1977). 

3.0 Process Description

The MED radiation work at Hooker Electrochemical was the concentration of uranium from 

slag, which had been sent to the Hooker site from the Electrometallurgical Company (DOE 

1985). This material was primarily reduction bomb (dolomite) liners with an approximate 

composition of 90% magnesium fluoride and 10% calcium oxide. (The term bomb, as used here, 

refers to a device used to contain a particular chemical process.) The slag reportedly contained 

approximately one pound of uranium per 500 pounds of slag (MED 1944). A description of the 

process is contained in a Data Sheet for Industrial Hazards, dated December 8, 1944 (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. 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.

3.1 Uranium Concentration

The incoming material is assumed to have a uranium concentration of 0.2% by mass. This 

comes from the process description of 1 pound of uranium in 500 pounds of slag. The 

description indicates the uranium was concentrated from one pound to five or ten pounds 

indicating the incoming slag had a concentration of 1 pound of uranium per 500 pounds of slag. 

It should be noted that the first page of the Data Sheet indicates the uranium concentration was 

as high as 1% uranium in the slag. This page indicates the material was 90% Magnesium 

fluoride, 10% calcium oxide and 1% “X” (an MED code for uranium). These values add up to 

101% indicating they are an approximation. Also, it should be noted that the process was to 

concentrate uranium and there is no indication whether these values are describing the incoming 

slag or the outgoing concentrate. 

In order to address this, two documents from Mallinckrodt Chemical Works in St. Louis 

(Mallinckrodt) were found. The first document from 1949 indicates the slag from the metal 

process contains about 0.3% uranium (Lynch 1949). The second from 1965 indicates 4000 tons 

of C-liner slag containing 49 tons of uranium was stored at a waste site (Miller 1965). This 

equates to approximately 1.2% uranium concentration. To reconcile these values, it should be 

noted that the second document also indicates that Mallinckrodt began recycling MgF2 liners in 

1953. In that process, the MgF2 was used as a liner multiple times. This would increase the 

concentration of uranium after each use. Since the first document was written before this 
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recycling began (1949) and the second written after the recycling began, it is possible some or all 

of the slag mentioned in the second document was recycled. Since the 0.3% value was 

documented before recycling began, the value should be considered most applicable to the 

material that would have been found at Hooker while the 1.2% value is questionable.

Lastly, if the incoming material had a uranium concentration of 1%, the Hooker process 

description does not appear to make sense. A 1% concentration would equate to 5 pounds of 

uranium in 500 pounds of slag. If that were true, the mention of one pound of uranium in the 

description makes no sense. Also stating that the slag was concentrated to 5 pounds would make 

no sense. 

Therefore, based on the indications in the Hooker process description, the uranium concentration 

will be assumed to be 0.2% for the incoming slag and 2% (10 pounds in 500 pounds of 

concentrate) in the outgoing concentrate. 

3.2 Monthly Production Rate

The Data Sheet indicates approximately 10 tons of material per month was processed. This 

appears to correlate well with a War Department memo dated 3/8/1946 that requested medical 

clearance for the termination of the Hooker Electrochemical contract. This memo indicated a 

total of 152 tons of slag were processed through this system and that it operated from July 1944 

through January 15, 1946 (Mears 1946). At 10 tons per month, this timeframe would equal 180 

tons. The difference in the two values is likely due to a slower rate at the beginning of the work 

and the likelihood that the work was performed for a shorter time frame. 

It is not clear from this documentation if the values above are related to the incoming slag or the 

outgoing concentrate. In order to determine this, an evaluation of the quantity of MgF2 produced 

by the MED was performed. The MED produced 2969 tons of uranium metal between 1942 and 

the end of 1945 (AEC 1951). There is approximately 0.432 pounds of liner per pound of UF4

(Thayer 1955). This correlates to 0.523 pounds of liner per pound of uranium or 1554 tons of 

liner produced by the MED between 1942 and 1945. Much of this was produced at 

Mallinckrodt. Even assuming that Electromet produced as much uranium metal as Mallinckrodt, 

the total amount of slag produced at Electromet would be 777 tons. Not all of this slag was sent 

to Hooker. At least some was sent to Lake Ontario Ordnance Works for storage (AEC 1949). 

Also, the description of the process at Hooker (MEC 1944) indicates the rate was sufficient to 

take care of the waste HCl. This implies neutralizing the HCl was the limiting factor, not on the 

rate that slag was produced at Electromet. Therefore, the rate the slag came into Hooker should 

be less than the rate it was produced at Electromet. 

If the 10 tons per month describes the outgoing concentrate and the material was concentrated by 

only a factor of 5, the incoming would have to be 50 tons per month. Over an 18 month period, 

that is 900 tons of material coming in. Since some of the material was too large for the process 

and was thus redrummed without processing, the incoming would have to be even higher. 

Combining that with the fact that much of the slag was sent to LOOW, it appears the 10 tons per 

month cannot be describing the outgoing concentrate. Therefore, the 10 tons per month will be 

assumed to describe the incoming slag. 
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3.3 Daily Production Rate

Slag coming in at a rate of 10 tons per month represents 40 barrels weighing 500 pounds each. 

There are only limited indications as to how long it took workers to empty these barrels. One 

former worker remembered the process started by dumping approximately 20 to 25 barrels per 

day then increasing to 40 barrels per day (Personal Communication 2009). It is questionable 

however whether this employee was discussing this particular project. Several inconsistencies in 

his recollection combined with the fact that the employee indicated they were not told what the 

material was leads to the realization that he may have been working on some other project at 

Hooker. However, the process he described includes many of the same aspects as the MgF2 slag 

project (emptying drum, screening the material, redrumming oversized material) and is therefore 

a good indication of the typical pace of such work at Hooker at the time. Therefore, it is 

assumed that the 10 tons per month of slag contained in 40 barrels was emptied in one day. 

4.0 Internal Dose

No data were found in the Site Research database related to occupational internal dose during 

MED work. The work performed at Hooker Electrochemical involved concentrating C-2 slag. 

Much of that work involved either liquid or material with a high moisture content which would 

result in little or no airborne activity. The one task involving dry material was the dumping of 

barrels of MgF2 slag. The slag came directly from the nearby ElectroMet facility. Two air 

sample results from handling this material at ElectroMet were found. The first result was an 

average of an unknown number of samples taken on December 24, 1947, March 30, 1948 and 

May 14, 1948. The average of the samples was 456 dpm/m3. The second result was an average 

of three samples taken between August 17th and the 19th of 1949. The average value was 398 

dpm/m3. Work associated with these samples included shoveling the material into the barrels. 

Since there are only two results and they were reported as averages, they provide little 

information about the variability of the data. Therefore, additional samples associated with 

handling MgF2 were found at Mallinckrodt and Fernald. These samples are listed in Table 1. 
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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

These samples were used to determine the parameters of a lognormal distribution. The analysis 

resulted in determining a geometric standard deviation (GSD) of 2.43 and a geometric mean 

(GM) value of 187.7 dpm/m3. The 95th percentile of this distribution is 806 dpm/m3

. Figure 1

shows the individual data points along with the fit associated with these parameters. 
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Figure 1: Air Sample Distribution 

Drum dumping is the highest airborne causing evolution at Hooker but it was performed only 

one day per month. The next highest airborne causing evolution would be the filtering and 

drumming of the concentrate after digestion. The remaining operations were performed in a 

liquid system. In order to determine an intake associated with filter operations, measurements 

associated with the digestion of uranium concentrates were considered. Digestion of 

concentrates involves many of the same basic steps as the concentration of MgF2 at Hooker. A 

report by Christofano and Harris (Christofano 1960) determined the range of airborne activity 

associated with digesting uranium concentrates to be between 17 dpm/m3and 100 dpm/m3 with 

an average concentration of 40 dpm/m3. They also noted the uranium concentration in the 

incoming concentrate was 70% to 90% U3O8. Using the average (80%) equates to a uranium 

concentration of 68%. The concentrate being filtered at Hooker is 2% uranium. Adjusting the 

highest air concentration (100 dpm/m3) down to 2% uranium produces a uranium airborne 

concentration of 2.95 dpm/m3. 

The internal dose estimate for Hooker will assume individuals are exposed to slag dumping 5% 

of the time (1 day per month) and the airborne concentration associated with filter operations the 

remaining 95% of the time. The 95th percentile of the slag distribution (806 dpm/m3) will be 

used along with the bounding value (2.95 dpm/m3) for the filter operation. This produces an 

average airborne concentration of 43.1 dpm/m3. It is further assumed that the operators worked 

48 hours per week for 50 weeks per year resulting in 2400 hours of work per year. This results 

in an intake rate of 340 dpm/calendar day. 

The airborne concentration was also used to determine an ingestion intake per OCAS-TIB-0009

(OCAS 2004). This results in an ingestion intake of 5.9 dpm/calendar day. 

5.0 External Dose
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No external dosimetry data were found related to occupational external dose at Hooker during 

the MED work. Therefore, external dose was modeled using the computer code MCNPX 

(LANL 2009). External dose associated with the incoming barrels of slag (0.2% uranium) was

modeled as well as with a barrel of uranium concentrate (2% uranium) and surface 

contamination. 

5.1 Slag Barrel

The slag was reported to have arrived in wooden barrels with 500 pounds of slag in each barrel. 

The barrel was modeled as a cylinder. The material was assumed to be contained within a 50 

gallon volume 36 inches high. The reported composition of the slag was 90% MgF (assumed to 

mean MgF2), 10% CaO and 1% X (a code for uranium). These values sum to 101% and 

therefore must be adjusted. The uranium was assumed to be in the form of UO2 since small 

particles of uranium would readily oxidize. As discussed in section 3.1 the uranium 

concentration is assumed to be 0.2% by weight. The percentages of MgF2 and CaO were 

reduced proportionally so that the entire composition added to 100%. This results in a 

composition of 0.23% UO2 (0.2% uranium), 89.80% MgF2 and 9.98% CaO. 500 pounds of 

material contained in a 50 gallon space results in an average density of 1.2 g/cc. The uranium 

was assumed to be naturally enriched with short-lived decay products in equilibrium with their 

parent radionuclides. The shielding that would be provided by the barrel walls was ignored. 

MCNPX was utilized to calculate the dose rate from direct photons and bremsstrahlung x-rays at 

a distance of one foot and one meter from the barrel. Dose conversion coefficients listed in 

ICRP 1996 Table A.1 were utilized for this calculation. The dose rate from beta particles was 

determined directly above the barrel on contact and one foot above the barrel. Dose conversion 

coefficients from ICRP 1996 Table A.43 were utilized for this calculation. The resulting dose 

rates are shown in Table 2.

Table 2: Slag Barrel External Dose Rates 

Photons

(mr/hr)

Betas

(mrem/hr)

Contact N/A 1.91E-01

1 foot 1.94E-03 4.61E-02

1 meter 5.78E-04 N/A

5.2 Concentrate Barrel

After digestion and filtering, the filtered concentrate was placed into barrels. This was also 

modeled using the same assumptions as the slag barrel except the uranium concentration was 

assumed to be 2%. The composition of the concentrate was then 2.27% UO2 (2% uranium), 

87.96% MgF2 and 9.77% CaO. 

The calculated dose rates from the concentrate barrel are shown in table 3.
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Table 3: Concentrate External Dose Rates 

Photons

(mrem/hr)

Betas

(mrem/hr)

Contact N/A 1.93E+00

1 foot 1.65E-02 4.44E-01

1 meter 4.91E-03 N/A

5.3 External Dose from Surface Contamination

Next the external dose rate from surface contamination was calculated again utilizing the 

computer code MCNPX. The model assumed a large area of contamination (circle with a 100 

meter diameter). The contamination was assumed to be evenly distributed over the area. The 

radioactive components of the contamination were assumed to be naturally enriched uranium in 

equilibrium with its short-lived decay products. The dose rate one foot from the surface was 

calculated assuming a contamination of 1 dpm/m2

alpha activity. This produced conversion 

factors that could then be multiplied by the surface contamination values to obtain external dose 

rates. The result of these calculations is shown in Table 4. 

Table 4: Surface Contamination External Dose Rates

Conversion factor Dose Rate

Photon 6.79E-10 mr/hr per dpm alpha/m21.90E-04 mr/hr

Beta 6.04E-08 mrem/hr per dpm alpha/m21.69E-02 mrem/hr

The surface contamination level was estimated by assuming the airborne activity deposited with 

a velocity of 0.00075 m/s. The airborne activity used was the average activity from section 4.0

(43.1 dpm/m3

). The airborne was assumed to deposit for 2400 hours (one full work year) 

without any removal mechanism. This resulted in a surface contamination level of 279410

dpm/m2. This value was multiplied by the conversion factors in Table 4 to obtain the estimate of 

external dose rates due to surface contamination. The resulting dose rates are also contained in 

Table 4. 

All beta exposure is entered into IREP as electrons >15keV. Energy distribution of the photon 

exposure rate from surface contamination was also calculated using MCNPX. The energy 

distribution was determined to be 80.2% <30keV, 12.3% 30 to 250 keV and 7.5% >250 keV. 

These values should be used in calculating photon dose. 

5.4 External Dose Summary

Operators are assumed to spend 1 day per month (5%) emptying barrels of slag. A similar 

amount of time is assumed to be spent loading concentrate into barrels. Additionally, operators 

are assumed to be exposed to external radiation from surface contamination 100% of the time. 

Laborers are assumed to be in the area 100% of the time but not directly handle the material. As 

such, they are assumed to be exposed 100% of the time to external radiation from surface 

contamination. Supervisors are assumed to spend 50% of their time in the area but not directly 

handle material. Clerical or other individuals are assumed to be in the area 5% of the time but 

not directly handle material. 
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While handling the material directly, operators are assumed to spend 50% of their time one foot 

from the barrels and the remaining 50% of the time one meter from the barrels. The operators’ 

hands are assumed be in contact with the material the entire time they are one foot from the 

barrels. The annual doses were calculated for photon dose, skin of the whole body (WB-skin) 

and the hands and forearms. The overall external dose estimates for operational periods are 

shown in Table 5. 

Table 5: External Dose Summary 

Photon

(mr/yr)

WB-Skin

(mrem/yr)

Hands and forearms

(mrem/yr)

Material Dose

Operators 1.43E+00 2.94E+01 1.27E+02

Contamination Dose

Operators 4.55E-01 4.05E+01 4.05E+01

Laborers 4.55E-01 4.05E+01 4.05E+01

Supervisors 2.28E-01 2.03E+01 2.03E+01

Clerical 2.28E-02 2.03E+00 2.03E+00

The photon doses from material should be entered into IREP as 30keV to 250 keV photons with 

a constant distribution. Photon doses from contamination should be entered into IREP as a 

constant distribution with the energy distributed as 80.2% <30 keV, 12.3% 30 to 250 keV and 

7.5% >250 keV. The WB-skin and hands and forearms doses should be entered as electrons 

greater than 15 keV with a constant distribution. The 1944 and 1946 doses should be prorated to 

the fraction of the year the operation occurred based on a start date of July 11, 1944 and an end 

date of January 15, 1946.

6.0 Residual Contamination

For the purposes of this document, the residual contamination period at Hooker Electrochemical 

is considered to begin on January 15, 1946 and end on October 11, 1976. The end date is based 

on the Residual Contamination report (NIOSH 2009) and the date of the radiological survey that 

concluded that no elevated levels of radioactivity were onsite (DOE 1977 pg 11). 

The external dose rates used during this period are the dose rates contained in section 5.3 from 

the surface contamination. 

The internal dose rates are based on the surface contamination values derived in section 5.3 

combined with a resuspension factor of 1x10-6 m-1. NUREG-1720 provides this value as the 

Nuclear Regulatory Commission’s recommendation of an appropriate resuspension factor for 

license termination screening. The recommendation indicates a resuspension factor of 1x10-6 m-1

is more realistic than the previous value of 1.42x10-5 m-1 and sufficiently conservative for 

screening analysis. In this analysis, the NRC noted a significant difference between those studies 

conducted in areas with freshly deposited contamination versus those involving “operating 

facilities or those undergoing decommissioning”. Since the NRC report was associated with 

decommissioning, they chose to not use those studies involving freshly deposited contamination. 
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The basis for this decision was the assumption that any area undergoing decommissioning would 

likely be washed down. 

At Hooker, the majority of the airborne contamination (and thus the surface contamination) was 

located where the slag drums were emptied. This work was accomplished outdoors on a 

concrete pad near the railroad spur. As such, the contamination was exposed to the elements in 

western New York State. Wind, rain, and snow melt would quickly accomplish the same effect 

as washing down the area with a water hose. Therefore the resuspension factor from NUREG1720 appears to be applicable at Hooker. 

The surface contamination value is based on a bounding estimate of the airborne levels deposited 

for 2400 hours with no removal mechanisms. The surface contamination value is then a 

bounding value. Since both the internal and external exposure estimates are based on this 

bounding value, the dose estimated during the residual period will be entered into IREP as a 

constant. 

The internal and external values applicable to the residual period are shown in Table 6. 

Table 6: Residual Period Dose Summary 

Internal Dose

Job Category Years Nuclide Intake (dpm/calendar day)

All jobs 1946-1976 U-234 2.20

External Dose

Job Category Years Photons (mr/yr) Skin (mrem/yr)

Operators 1946-1976 4.55E-01 4.05E+01

Laborers 1946-1976 4.55E-01 4.05E+01

Supervisors 1946-1976 2.28E-01 2.03E+01

Clerical 1946-1976 2.28E-02 2.03E+00

All internal dose is entered into IREP as alpha radiation with a constant distribution. External 

photon dose should be entered into IREP as a constant distribution with an energy distribution of 

80.2% <30keV photons, 12.3% 30 to 250 keV photons and 7.5% >250 keV photons. External 

skin doses should be entered into IREP as a constant distribution of electrons >15keV. 

7.0 Occupational Medical Dose

The War Department memo dated March 8, 1946 indicated the medical requirements included a 

pre-employment exam including a chest x-ray as well as a monthly blood count and monthly 

urinalysis. It also indicates there were no special exams and that this schedule was not adhered 

to after the first year of operation (Mears 1946). No other information regarding occupational 

medical dose specific to Hooker Electrochemical was found. Information to be used in dose 

reconstructions for which no specific information is available is provided in ORAUT-OTIB0006, the dose reconstruction project technical information bulletin covering diagnostic x-ray 

procedures. The assigned frequency should be only a pre-employment PA chest x-ray. 
Effective Date: 

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8.0 References

AEC 1949, Atomic Energy Commission, SF Material Accounting Procedure Manual for the 

Tonawanda Sub-Office of the New York Operations Office, July 15, 1949, SRDB 61025 pg. 192

AEC 1951, Atomic Energy Commission, The Production of Uranium Feed Material, May 22, 

1951, SRDB 4125 pg 77 

Christofano 1960, The Industrial Hygiene of Uranium Refining, Emil Christofano and William 

B. Harris, November 1960, SRDB 15774 

DOE 1977, U.S. Department of Energy, 1977, Formerly Utilized MED/AEC Sites Remedial 

Action Program, Radiological Survey of the Hooker Chemical Company, Niagara Falls, New 

York, Final Report, Washington, D.C., January 1977, SRDB 10797

DOE 1985, U.S. Department of Energy, 1985, Formerly Utilized Sites Remedial Action Report

Elimination Report for Occidental Chemical Corporation (Former Hooker Electrochemical 

Company) Niagara Falls, New York, Washington, D.C. SRDB 11002 pp. 58

DOE 2009, Office of Health, Safety and Security, EEOICPA web site. 

http://www.hss.energy.gov/healthsafety/fwsp/advocacy/faclist/findfacility.cfm 

Dowling 1944, Dowling, Francis A., c. 1944, Completion Report, Construction of Hooker 

Electrochemical Company P-45 Plant, Contract No. W-7405-ENG-28, Tonawanda AreaManhattan District, SRDB 11002 pp. 102-112

ICRP 1996, International Commission on Radiological Protection (ICRP), Conversion 

Coefficients for use in Radiological Protection against External Radiation, Publication 74, 

Annals of the ICRP, 26 (3/4) 

LANL 2009, MCNP5/MCNPX: Monte Carlo N-Particle Transport Code System Including 

MCNP5 1.60 and MCNPX 2.6.0 and Data Libraries, Los Alamos National Laboratory, Los 

Alamos, New Mexico. 

Lynch 1949, Memorandum from D. E. Lynch, “Waste Disposal, Mallinckrodt Plants”, February 

9, 1949, SRDB 11173 pg 2 

Mears 1946, Mears, B.J., 1946, memorandum to The District Engineer, “Medical Clearance on 

Terminated Madison Square Area Contracts,” Manhattan District, Oak Ridge, Tennessee, March 

8, 1946, SRDB 17125 pp. 29-30

MED 1944, Manhattan District, 1944, “Medical Section – Manhattan District, Data Sheets for 

Industrial Hazard Rating”, SRDB 16323 pp. 29-30

Miller 1965, Airport Committee, R. H. Miller Chairman, Committee Report on Disposition of St. 

Louis Airport Storage Site, November 5, 1965, SRDB 74542 
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NIOSH 2009, National Institute for Occupational Safety and Health 2009, Report on Residual 

Radioactive and Beryllium Contamination at Atomic Weapons Employer Facilities and 

Beryllium Vendor Facilities. http://www.cdc.gov/niosh/ocas/pdfs/tbd/rescon/rcontam1206.pdf 

NUREG-1720, U. S. Nuclear Regulatory Commission, Re-evaluation of the Indoor 

Resuspension Factor for the Screening Analysis of the Building Occupancy Scenario for NRC’s 

License Termination Rule, June 2002

OCAS 2004, Office of Compensation Analysis and Support, Technical Information Bulletin: 

Estimation of Ingestion Intakes, Rev 0, OCAS-TIB-0009, April 13, 2004 

ORAUT-OTIB-0006, ORAUT (Oak Ridge Associated Universities Team), Technical 

Information Bulletin: Dose Reconstruction from Occupationally Related Diagnostic X-Ray 

Procedures, Rev 03 PC-1, December 21, 2005. 

Olotka, 1979, Letter from F.T. Olotka to William E Mott regarding review and comments of a 

March 1979 letter to J Gallery, April 18, 1979, SRDB 11002 pp. 39 

Personal Communication 2009, Personal Communication with Former Hooker Electrochemcial 

“Yard Gang” Employee; Telephone Interview by ORAU Team, December 12, 2009, SRDB 

77827

Thayer 1955, Letter from Harold E. Thayer to F. H. Belcher, Capacity Slag Grinding Plant, May 

13, 1955, SRDB 4012