DEPARTMENT OF THE AIR FORCE
HEADQUARTERS AIR FORCE SAFETY CENTER
MEMORANDUM FOR INSTALLATION SAFETY OFFICE
FORT BLISS, TEXAS
ATTN: MS. AKIN
3 July 2013
FROM: HQ AFSC/SEWN
9700 G Ave, SE
Kirtland AFB NM 87117-5670
SUBJECT: Trip Report, Inspection of Former Air Force Weapons Storage Area (WSA), Biggs
Army Airfield, Fort Bliss, TX, 26 June 2013
REFERENCE: “Technical Guidebook to Permitting, Investigations, and Remedial Actions on
Air Force Section 91b Radiological Sites,” Air Force Institute for Operational
Health, Brooks City-Base, TX, 28 March 2008, FOUO.
1. We have been in consultation with your office and Mr. Joel Reyes, the Fort Bliss environmental
restoration program manager, this spring regarding the former Air Force (AF) weapons storage area
buildings and land areas, and their potential for radiological impacts from past nuclear weapons
storage and maintenance operations. Research and review of our records culminated in a site visit
on 26 June with you, Mr. Reyes, and Mr. Timothy Hodsdon, the Airfield Safety Officer, to compare
historical information with present conditions.
2. Background.
a. Headquarters, AF Safety Center, Weapons Safety Division (HQ AFSEC/SEWN) has
responsibility within the AF for oversight on residual radioactive materials from past nuclear
weapons operations. Details on the program are contained in the reference document, which was
provided to your office this spring. The real property that contained four former AF bases with
nuclear weapons operations are now under the responsibility of the Department of the Army: Gray
AFB, TX (Fort Hood), Hunter AFB, GA (Fort Stewart), Clarksville AFB (Fort Campbell), and the
subject of this letter, Biggs AFB. Though the AF does not have any authority over these sites, we
have offered to provide technical assistance to Fort Bliss due to our experience gained managing
numerous sites under AF management. The radioactive materials associated with these operations
were not subjected to the regulatory authority that is currently exercised by the Nuclear Regulatory
Commission (NRC) and previously under the Atomic Energy Commission (AEC) within the scope
of the exemption provided in Section 91b, Atomic Energy Act of 1954 (42 USC §2121 et seq.). The
exemption remains applicable.
b. The Biggs AFB WSA supported a Strategic Air Command (SAC) mission that ceased in
1966. We understand that a few years later the Army reactivated use of the airfield. Figure 1-1,
Attachment 1, contains a current aerial image of the igloo storage area within the former WSA, with
current building numbers associated with individual structures. According to nuclear weapon
Unpainted
Painted 1
Painted 2
Painted 3
Alpha channel
3
178
471
798
Beta channel
353
668
646
848
NA
1.8
0.63
0.62
NA
1,775
1,651
2,789
* Assumptions of: dominating HEU activity, Ludlum Model 43-89 Probe Area of 125 cm2, near equivalence of Tc-99
beta-particle detection efficiency to field-detectable emissions from HEU, and negligible attenuation of beta particle
emissions from paint.
c. The two areas noted by Mr. Oskins as being possible locations where wasted were buried
were evaluated for visual evidence. The southern area was investigated first. Some metallic debris
was located throughout the area, including chain linked fence sections, as shown in Figure 4-1,
Attachment 4. As pointed out by Fort Bliss staff, chain linked fence sections could be located
throughout the area, but may not have been likely used to delineate a waste burial area. The northern
location identified by Mr. Oskins as the possible burial location contained a square area with
remnants of wooden posts that supported barbed wire and chicken-wire style fence material. Images
of this area are in Figures 4-2 and 4-3. This area had the appearance of a fenced burial area, though
it was north of the original installation boundary fence shown in Figure 1-2 that extends from the
southwest to northeast, meeting the WSA fence.
4. Discussion.
a. The contamination identified on the floor of building 11507 corresponded well with the
statements of the two veteran’s. Based on the relationship between the net alpha and beta count
rates, and the residual paint existing in this area, we believe the contamination is dominated by a
HEU component. The figure below displays the field-detectable beta particle emission rates versus
the alpha particle emission rate for various isotopic compositions of uranium from the reference
document. The paint as originally applied would have provided a near complete masking of all
alpha particle emissions from the contaminated floor surface. A visual inspection of the floor
indicated that some isolated portions of the painted area had obvious degradation of the paint surface
that would explain some ability to detect alpha particle emissions from the surface contamination.
However, the paint was not degraded to a significant degree and it is our judgment that a substantial
fraction of the alpha particle emissions in the upward 2 solid angle are being absorbed by the paint,
though the paint is not sufficiently thick to afford much absorption of beta particle emissions. As
such, the net beta particle emission rate is a more defensible index of the contamination levels in
Frequency of Field-Detectable  -Particle
Emissions per  -Emission
5
1.6
1.41
1.2
0.84
0.8
0.4
0.028
0.036
0.057
0.08
0
Moderate DU HEU (93.3 %) HEU (67.7 %) HEU (38.5 %) HEU (20 %)
Tuballoy
Isotopic Composition
Figure. Frequency of Field-Detectable -Particle Emissions per -Emission for Various
Isotopic Uranium Isotopic Compositions [Figure 3-2 of Reference Document].
comparison to the alpha particle emission rate. If the contamination was dominated by DU, under
these circumstances with a residual paint layer, the net beta to alpha radiation emission rates would
have been substantially higher than that observed for our measurements.
b. The table contains estimated beta radiation surface activity concentration levels for the
three measurements in the painted area and under the assumptions listed in the footnote to the table.
From a conservative standpoint, if the contamination was 93.3 % HEU, the surface alpha radiation
contamination concentrations would be 35.7-fold higher than the beta radiation contamination levels,
i.e., (1 ÷ 0.028). Since there is a 1:1 correlation in the alpha particle activity concentration to the
total residual uranium levels for HEU or DU, the total uranium activity concentration level for the
measurement at location “Painted 3” would be about 100,000 dpm/100 cm2. This level is in excess
of the acceptable maximum level in AEC Regulatory Guide 1.86 for uranium isotopes. A copy of an
adapted version of the guide contained in AF Instruction 48-148 is provided in Attachment 5. The
AF generally uses this guide as an unrestricted release criterion for building surfaces. It is important
to note, however, we have made conservative assumptions in estimates of uranium surface
contamination concentrations. In addition, the dominant exposure risk from surfaces contaminated
with HEU is the potential for internal exposure potential, e.g., inhalation and/or ingestion. This
potential is normally assessed by a surface wipe sample, which was not conducted during our visit.
The paint on the surface still limits the potential for loose contamination potential, as compared to a
similar contaminant on an unpainted surface. The simplified analysis provided here is for
informational purposes only. The Army may desire to perform a more in-depth analysis, including
evaluation against appropriate Army standards.
c. The fenced area identified in the vicinity of the one northern location suspected by the
veteran for containing the past burial site was a promising finding from our visit. The veteran
6
believed that they exited the WSA from the southernmost entrance and hand-carried the waste to the
burial area. Due to the existence of the fence traversing the area on the outside of the WSA, access
by foot would not be possible. During our visit, another entrance to the southern portion of the WSA
existed on the west side, just north of this fence. This entrance point is actually closer to the M&I
building that the veteran noted as the location most of their work was accomplished and location
from which they carried the waste containers to the burial site on the outside of the WSA. It is
possible that veteran did not recall which entry point to the WSA they used to accomplish this task.
5. We hope that this information is beneficial to evaluation of radiological contamination potential
in buildings and former burial sites at the former Biggs AFB WSA. I greatly appreciate the
hospitality extended by you, Mr. Reyes, and Mr. Hodsdon during my visit. We stand ready for to
provided additional technical assistance in evaluation of these sites as more information becomes
available. Our collaboration on this project is also important to our continued assessment of AF
sites, as findings for the former Biggs AFB WSA may have parallels to other sites. For our
continued collaboration, please contact me at DSN 246-0450 (commercial: 505-846-0450) or
electronic mail: Steven.Rademacher@kirtland.af.mil.
RADEMACHER.STE
VEN.E.1099705783
Digitally signed by
RADEMACHER.STEVEN.E.1099705783
DN: c=US, o=U.S. Government, ou=DoD,
ou=PKI, ou=USAF,
cn=RADEMACHER.STEVEN.E.1099705783
Date: 2013.07.03 10:40:48 -06'00'
STEVEN E. RADEMACHER, GS-14, DAF
Chief, Radioactive Materials Licensing and Safety
Attachments
1. Satellite Images of Former WSA Area at Biggs AFB
2. Photographs of the Interior of Building 11507
3. Calibration Certificate for Ludlum Model 2360 Probe
and Model 43-89 Probe Combination
4. Photographs of Land Areas Inspected
5. Atomic Energy Commission Regulatory Guide 1.86
[Adapted Version in AF Instruction 48-148]
cc: HQ AFSEC/SEWN (Mr. Carrillo)
Attachment 1. HQ AFSEC/SEWN Ltr to Installation
Safety Office, Fort Bliss, TX, 3 July 2013
Figure 1-1. Satellite Image of Former WSA Area at Biggs Army Airfield, Fort Bliss, Texas
Storage Igloos
C-Structures
11500
11505
11506
11507
11509
11511
11512
11513
Former Location of
Building 11508
(Residual Slab Only)
11514
Attachment 1. HQ AFSEC/SEWN Ltr to Installation
Safety Office, Fort Bliss, TX, 3 July 2013
TABLE 1-1. Former WSA Building Details.
Building
Number
11500
11505
11506
Building Interior
Dimensions
26’ W x 62’ D
26’ W x 62’ D
26’ W x 82’ D
Building
Type
Igloo
Igloo
Igloo
11507
26’ W x 54’ D
C-Structure
11508
Previously
Removed
NA
11509
11511
11512
26’ W x 62’ D
26’ W x 62’ D
26’ W x 82’ D
Igloo
Igloo
Igloo
11513
26’ W x 54’ D
C-Structure
11514
26’ W x 82’ D
Igloo
Notes
Single pour concrete floor.
Single pour concrete floor.
Six-slab (3 x 2) concrete floor.
Large interior concrete room, with “bank-vault”-type
door and metal storage shelves. Design matches style
for storage and maintenance operations on early,
unsealed nuclear munitions.
Small concrete slab residual. Appears to have
supported former metal building, perhaps for
flammable material storage.
Single pour concrete floor.
Single pour concrete floor.
Six-slab (3 x 2) concrete floor.
Igloo front section administrative room, single door
entrance to larger rear section that contains small
interior concrete room. Room had “bank-vault”-type
door and metal storage shelves. Design matches style
for storage and maintenance operations on early,
unsealed nuclear munitions.
Multiple slab floor.
Attachment 1. HQ AFSEC/SEWN Ltr to Installation
Safety Office, Fort Bliss, TX, 3 July 2013
Figure 1-2. Satellite Image of Former WSA Area at Biggs Army Airfield, Fort Bliss, Texas
Historical WSA
Boundary Fence
Maintenance &
Inspection (M & I)
Building
AFK Warehouse
Generator
Building
Historical Weapons
Maintenance Waste
Burial Site (Only One
of the Two Locations)
Guard
House
Dog Kennels
Attachment 2. HQ AFSEC/SEWN Ltr to Installation
Safety Office, Fort Bliss, TX, 3 July 2013
Figure 2-1. Steel Storage Shelves in Vault in
Building 11507, Vault Door to Right.
Figure 2-2. Painted Area on
Floor in Building 11507.
Figure 2-3. Detector Probe Over Contaminated Floor Area, Adjacent to Igloo Concrete Exterior Wall.
Attachment 3. HQ AFSEC/SEWN Ltr to Installation
Safety Office, Fort Bliss, TX, 3 July 2013
DEPARTMENT OF THE AIR FORCE
USAF SCHOOL OF AEROSPACE MEDICINE (AFMC)
OCCUPATIONAL ENVIRONMENTAL HEALTH
WRIGHT-PATTERSON AFB OHIO
CERTIFICATE OF CALIBRATION
Mfg. Ludlum
Mfg. Ludlum
Model 2360
Model 43-89
Serial # 278626
Index# 102117
Index # N/A
Serial # PR311680
Date:
26-Mar-13
Cal. Due Date: 26-Mar-14
TEST, MEASUREMENT AND DIAGNOSTIC EQUIPMENT
NIST Traceable Check Sources
Reference Instruments
Isotope
Serial #
Cert. Date
EPM
Mfg.
Model
Serial #
Arn-241
RP3076 30 Sep 04 21426
Ludlum
500-1
102952
Tc-99
RP3 073 28 Sep 04 29752
Cal. Due Date
30 OCT 2013
Measurement Standards and test equipment used are traceable to the National Institute of Standards and Technology, to the extent allowed by the Institute’s
calibration facilities.
Battery Ck.EMechanical Ck.Meter Zeroed
Geotropism Ck.
EAudio Ck.
817
AsFounciHV
Volt. Set
800
V Beta Threshold
HV Readout (2 points)
RANGE
MULTIPLIER
xl000
xl000
xlOO
xlOO
x 10
xlO
x1
xl
3.5
Reference:
Inst. Readout:
my
500
500
REFERENCE
CAL. POINT
400
100
400
100
400
100
400
100
FIS Resp. Ck. EWindow Op.
70.90 °F
Temperature
VDC
±
30
mV
“AS FOUND”
READING
CPM
CPM
CPM
CPM
CPM
CPM
CPM
40,000 CPM
1000
1,000
V
V
± 2%
CORRECTED
READING
400,000 CPM
100,000 CPM
40,000 CPM
10,000 CPM
4,000 CPM
1,000 CPM
400 CPM
IOOCPM
CPM
23,70 %
Alpha Threshold 120 mV
Reference:
Inst. Readout:
2%
DIGITAL SCALER READOUT
AS FOUND READING
CAL. REF. POINT
Relative Humidity
Beta Window
V
V
AJarrn Ck.
Reset Ck.
400,000CPM
100,000CPM
40,000CPM
10,000CPM
4,000 CPM
1,000CPM
400 CPM
100CPM
CORRECTED READING
39,992 CPM
39,992 CPM
*UNCERTAINTY WITHIN ±10% CORRECTION FACTOR WITHIN ± 20%
COMMENTS:
Calibration Interval
EPM=2t Emission Rate per Mm
=
1 year
a Eff: 42.50 % 2t@1/4”
13 Eff:
28.40 % 2t( 1/4”
L
Calibrated By:
Reviewed By:
Procedural Authority ICP#23604389
-
Date: 27-Mar-13
Date:
7,
l6AP’,3
.
High Voltage
750
775
*80O
825
850
HIGH VOLTAGE DETERMINATION
Alpha Cross Talk
Background
Alpha Source
cross
talk % eff
Beta
Alpha
Beta
Alpha
1
0
0
2
1
109
179
178
212
245
8206
8731
9156
9123
9403
513
638
945
1718
4603
4.9%
5.3%
8.4%
16.5%
46.3%
38.3%
40.7%
42.7%
42.6%
43.9%
Beta Source
Beta
Alpha
0
5
0
1
2
Beta Cross Talk
cross talk % eft
6029 -0.02% 19.9%
7370 0.07% 24.2%
8444 0.00% 27.8%
9719 -0.01% 32.0%
10799 0.01% 35.5%
.1pha Source (Am-241) 2itEPM- 21,426
Beta Source (Tc-99) 2 it EPM 29,752
-
DETECTOR UNIFORMITY AND EFFICIENCY
Alpha Source Beta Source
Source Locatioi 21,426 DPM 29,752 DPM
Background
CPM
CPM
0
188
Heel 9266 CPM 9540 CPM
Center 9048 CPM 8363 CPM
Toe 8999 CPM 8001 CPM
Average 9104.3 CPM 8634.7 CPM
Effeciency (eJ
28.4%
42.5%
Calibrated By’2’
Date:
Reviewed By:
Date: !
7,
/5
Af i3
Attachment 4. HQ AFSEC/SEWN Ltr to Installation
Safety Office, Fort Bliss, TX, 3 July 2013
Figure 4-1. Loose Chain-Link
Fence On Ground.
Figure 4-2. Wooden Post with Barbed-Wire and
Chicken-Wire Style Fence Material.
Figure 4-3. Another Image of Area in Figure 4-2. Southern Section of WSA is in
Background and Mr. Reyes is in Image to Provide Perspective on Scale.
Attachment 5. HQ AFSEC/SEWN Ltr to Installation
Safety Office, Fort Bliss, TX, 3 July 2013
Atomic Energy Commission Regulatory Guide 1.86 (1974)
Acceptable Surface Contamination Levels. (Bracketed portion of notes
are extracted from AFI 48-148 and are not part of original)
Nuclidea
disintegrations/minute/100 square-centimeters (dpm/100 cm2)
Averageb c f
Maximumb d f
Removableb e
U-nat, 235U, 238U & associated decay
products
5,000 ()
15,000 ()
1,000 ()
Transuranics, 226Ra, 228Ra, 230Th, 228Th,
231
Pa, 227Ac, 125I, 129I
100
300
20
Th-nat, 232Th, 90Sr, 223Ra, 224Ra, 232U, 126I,
131 133
I, I
1,000
3,000
200
 emitters (nuclides with decay modes
other than -emission or SF) except 90Sr
and others noted above
5,000 ()
15,000 ()
1,000 ()
Notes:
a
Where surface contamination by both - and -emitting nuclides exists, the limits established for - and emitting nuclides should apply independently. [The values apply to radioactive contamination deposited on, but not
incorporated into the interior of, the contaminated item.]
b
As used in this table, dpm means the rate of emission by radioactive material as determined by correcting the
counts per minute observed by an appropriate detector for background, efficiency, and geometric factors associated with
the instrumentation.
c
Measurements of average contamination should not be averaged over more than 1 square meter. For objects of less
surface area, the average should be derived for each such object.
d
The maximum contamination level applies to an area of not more than 100 cm2.
e
The amount of removable radioactive material per 100 cm2 of surface area should be determined by wiping that
area with dry filter or soft absorbent material, applying moderate pressure, and assessing the amount of radioactive
material on the wipe with an appropriate instrument of known efficiency. [The use of dry material may not be
appropriate for tritium.] When removable contamination on objects of less surface area is determined, the pertinent
levels should be reduced proportionally and the entire area should be wiped. [Except for transuranics and 228Ra, 227Ac,
228
Th, 230Th, 231Pa, and -emitters, it is not necessary to use wiping techniques to measure removable contamination
levels if direct scan surveys indicate that the total residual surface contamination (i.e. removable and fixed) are within the
limits for removable contamination.]
[fThe average and maximum radiation levels associated with surface contamination resulting from -emitting
nuclides should not exceed 0.2 mrad/hr @ 1 cm and 1.0 mrad/hr @ 1 cm, respectively, measured through 7 milligrams
per square centimeter (mg/cm2) of total absorber.]