Pittsburg California Radiation Experiments covering half of the City

Spreading 10,000 rads of radiation onto the ground, roofs and lawns and how they cleaned it up. Note that the exposure to the personnel is only for the theoretical amount that future people would be exposed to while in this case, they were using lawn spreaders to put down 1000 and 10,000 rads of radiation. They also thought that these people were standing on clean ground, extending the brushes onto the contaminated ground. What happened to the people depicted in these photographs?

This article supplements my article with photographs and report text. “Pittsburg California Radiation Experiments, spreading radioactive sand onto barracks, lawns and streets of the former Camp Stoneman Base to train Sailors how to clean up after an atomic strike.”


Sartor, J D, Curtis, H B, Lee, H, and Owen, W L. COST AND EFFECTIVENESS OF DECONTAMINATION PROCEDURES FOR LAND TARGETS. United States/USNRDL-TR-196; NY 320-001-9; AD-153932 27 December 1957

The cost and effectiveness of basic radiological decontamination procedures for land target components were investigated at a field test conducted at Camp Stoneman in September 1956. Synthetic fallout was developed to provide contaminants simulating two types of radioactive debris, and two contaminating events were considered: (1) a dry fallout from a low-yield (kiloton) land burst, or a high-yield (megaton) land or shallow-water burst, and (2) a wet slurry fallout from a low-yield shallow-water burst. Areas contaminated at dose rates of 1,000 r/hr and 10,000 r/hr at 1 hour after burst were hypothesized to be situations of greatest interest and their dose rates were simulated according to the mass-radiation relationship of 25 mg/sq ft/r/hr at 1 hour.

The five procedures evaluated were combinations of the following basic methods: firehosing, hand scrubbing with and without detergent, motorized flushing and motorized scrubing with and without detergent.

Decontamination was tested on portland cement concrete and asphaltic concrete pavements; and composition shingle, tar and gravel, roll roofing-wood shingle, and corrugated galvanized steel roofs. The tests are described in detail and the cost and effectiveness of the various procedures are presented. Extrapolation of the data and application to actual situations are discussed.

For similar initial mass levels, slurry contaminant will, in all. probability, be more difficult to remove than the dry contaminant on paved areas, the motorized flushing procedure ranked lowest in effort expended. The firehosing procedure ranked lowest in effort expended on roofing areas.

The use of synthetic fallout in field operations of the nature and scope of the camp stoneman opex-ation is satisfactory. The decontamination procedures evaluated, with few exceptions, were 95 to 99 percent effective in the removal of the synthetic fallout material from paved areas and building roofs. A visual record of the study is in the moving picture Land Target Decontamination Tests, Stoneman Registry No. SHIPS 7-57


There is a general lack of accurate data applicable to the radiological recovery of land targets. In the most up-to-date generally available source, the manual, Radiological Recovery of Fixed Military Installations, NAVDOCKS TP-PL-13, August 1953, the values for cost and effectiveness of basic decontamination procedures were compiled in certain cases from inadequate data and best estimates.

This investigation was undertaken to obtain additional data in order to provide reliable decontamination values and also to obtain a statistically significant estimate of the experimental error.

Previous studies in the recovery of components of land targets have been conducted on a limited basis.

Decontamination studies were conducted on model buildings and paved areas at Operation JANGLE.2 The data gathered by the different participating groups were difficult to correlate due to variances in operating techniques and lack of uniformity in methods of radiation measurements.

Difficulty in obtaining contaminated test surfaces and unpredictability of weather conditions (two ever-present variables in nuclear weapon tests) also limited the significance and validity of the results to a great extent. Limited data were obtained from a field test conducted at the U.S. Naval Advance Base Personnel Depot, San Bruno, California. Liquid and slurry contaminate used at that time have been replaced by more realistic synthetic fallout formulated on the basis of data from laboratory research and nuclear weapon tests.

Tests also have been conducted at the Army Chemical Center to determine the effectiveness of gross decontamination techniques for radiological warfare (II) contaminate on asphaltic concrete road surfaces. However, the physical properties of the radioactive contaminates used for these tests limit the applicability of these data to probiems associated with fallout from nuclear detonations.

Page 1

Preparation of Synthetic Fallout:
The facilities at the Materials Testing Reactor, Arco, Idaho, 2 capsules were carried in each of 11
shipments by a U. S. Air Force aircraft from Arco, Idaho, to Travis AFB near Camp Stoneman, California. The La140 was prepared in a solution for mixing with the carrier from behind a concrete-block shielding wall by means of a pair of master slave manipulators.

[Note: This means there was a “hot cell” at Camp Stoneman to mix nuclear materials when they dismantled it and sold the buildings to developers to build housing in the Bay Area.]

The dry fallout simulant was prepared by combining the La140 solution and the Ambrose clay loam carrier in the mixing drum of a_modified Jaeger 3-1/2 cubic yard. transit-mix truck (Fig. 2.1). The lanthanum solution was pumped to a holding bottle on the side_of the transit-mix truck and fed to a pneumatic nozzle located in the head end of the rotating drum, where it was atomized. The liquid aerosol was adsorbed uniformly onto the bulk carrier material.
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figures page 7
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For the preparation of the slurry simulant, dried harbor bottom material was mixed with the lanthanum. in the transit-mix truck, transferred to a measuring hopper, and thence to the mixing tank of a modified Navy “crash trailer” (Fig. 2.2) where an equal weigt of fresh water was mixed with it. The 1:1 ratio of dry harbor bottom soil to fresh water was assumed to be typical of the actual fallout being simulated. The use of salt water was not necessary as the salt residue from the water after drying would not significantly affect the decontamination.

For the entire series of tests, approximately 40,000 lb of dry synthetic fallout and 31,000 Ib (wet weight) of slurry synthetic fallout were prepared. A small portion of this total was used for special tests conducted by the U. S. Forest Service and the U. S. Army Quartermaster Corps (see section 2.6).

2.2.1 Paved Areas

Dry simulant was dispersed over the paved areas from a modified Burch Hydron Spreader mounted on the roof of a 2-l/2 cu yd dump truck (Fig. 2.3). An aluminum hopper was installed on the truck to contain the synthetic fallout material and feed it directly into the spreader when the truck bed was raised. To reduce the effects of the wind, a fabricated aluminum extension was installed on the spreader which limited the free fall of the material to the ground to about 2 in. The layer of material simulating 1000 r/hr at 1 hour was approximately 0.008 in. deep and that for 10,000 r/hr, 0.083 in.

Slurry simulant was dispersed on the paved areas from a “crash trailer” (Fig. 2.2).

(Fig. 2.3) Dump Truck for Dispersing Dry Contaminate on Paved Areas.
(Fig. 2.4) Hand-drawn Spreader for Dispersing Dry Contaminate on Roof Areas.
[Note: What happened to this man, how much radiation was he exposed to by doing this?}

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2.2.2 Roof Areas

The dry simulant was dispersed over the roof areas and. test panels from a hand-drawn spreader (Fig. 2.4). An rpm meter was mounted on the spreader to aid in pulling the spreader at a constant speed. The slurry material was dispersed over the roof areas and panels from a hand-drawn “caddy cart”.


2.3.1 Cost Measurement

To determine the cost of the various decontamination procedures tested, the factors of manpower, equipment, and supplies were investigated.

Observations and records were made on:

a. Manpower requirements – the total munber of men required to perf rm the deconcontamination procedure, the working time, and the total time which included equipment set-up and dressing in protective clothing and changing back to normal garb.

b. Equipment and material requirements – the types, amounts, and rates of use of equipment and supplies.

2.3.2 Effectiveness Measurement

To determine the effectiveness of the various procedures, measurements were taken of the radiation levels present on the test areas just prior to contamination (background), after contamination, and after decontamination. Measurements were taken at twenty locations on each paved area and at 5 or 8 locations on each roofing area and panel, depending on its size.

Certain of the portland cement concrete areas were considered to be more cracked and broken than normally would be expected. Consequently, all the residual radiation measurements on or near the large cracks were discarded.

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a. Firehosing (FH)
b. Firehosing, Hand-Scrubbing, Firehosing,(FH-HS-FH)
c. Firehosing, Hand Scrubbing with Detergent, Firehosing (FH-BSD-FH)
d. Motorized Flushing. (MF)
e. Motorized Flushing, Motorized Scrubbing, Motorized Flushing
f. Motorized Flushing, Motorized Scrubbing With Detergent, Motorized Flushing (MF-MSD-MF)

A description of the procedures follows:
In (Fig. 2.7)

Equipment: A standard. 2-1/2-in. firehose running from a nearby fire hydrant to the test area where it fed two l-l/2-in firehoses; a 500-gpm portable pump inserted in the hose line near the hydrant to maintain a constant nozzle discharge pressure of 80 psig for all of the tests; a standard 1-l/2-in. playpipe with 5/8-m. nozzle orifice attached to each firehose.

Personnel: 6 to 8 men:

1 Supervisor
1 Pump Operator
2 or 3 Rose Tenders
2 or 3 Nozzle Men

Personnel: 6 to 8 men:

1 Supervisor
1 Pump Operator
2 or 3 Rose Tenders
2 or 3 Nozzle Men

Procedure: Starting at the higher end of the slope and proceeding down the length of the test area, the nozzle men advanced side by side pushing the Contaminant ahead and to each side. The rate of advance was determined visually, the work progressing as fast as the surface appeared to be cleaned.
FH-HS-FH (Fig. 2.8)

Equipment: The same as for FH” plus 4 to 6 10ng-bandled scrub brushes.

Personnel: 10 to 14 men:

1 Supervisor
1 Pump Operator
2 or 3 Hose Tenders
2 or 3 Nozzle Men
4 to 6 Scrubbers

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Procedure: The hose team started at the higher end. of the area and worked toward the low, proceeding· at a rate somewhat faster than the rate used for the FH procedure, as the purpose was to prewet the surface and remove the bulk of the contaminant.

When the hosing team had progressed a sufficient distance, and while the area still wet, the scrubbing team began, using short, brisk strokes until the area was thoroughly brushed.

When the scrubers had advanced approximately 50 ft” the hosing group returned to the starting point and commenced the final hosing. This last hosing was accomplished thoroughly at a rate comparable to that employed for the PH procedure. The scrubbers stepped aside as they were overtaken by the hose team, which continued into the next section of the test area, to perpetuate the cycle.


Equipment: The FH-HS-FH equipment plus the detergent (OBVUS (Industrial Form of Tide) and
a bucket for hand-washing it.

Personnel: The same as for FH-HS-FH plus one man for spreading detergent, 11 to 15 men.

Procedure: The detergent spreader followed the imtial hosing quite closely, hand-casting the detergent powder. In other respects, the procedure was the same as that used for FH-HS-FH.

MF (Fig. 2.9)

Equipment: A street-flusher truck of 3000-gal capacity and with a 500-gpm pump and two forward and one side discharge nozzles.

Personnel: A driver and one supervisor.

Procedure: The truck vas driven at approximately 5 mph, down the slope of the long dimension of the test area, the first pass being made along the high side of the cross slope. Successive adjacent passes were made over the full width of the area. The nozzles were directed to take advantage of the longitudinal. as well as the cross slope. Usually, 3 to 4 passes were sufficient to clean the 20-ft wide test strips.

MF-MS-MF (Fig. 2.10)

Equipment: The street flusher and a Wayne Street Sweeper, Model 1-450.

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Personnel: A driver for each of the two vehicles and one supervisor.

Procedure: Sufficient passes were made vitb the flusher to wet the test area. The test strip was then swept as clean as possible with the sweeper, as many as 8 passes being required. A second flushing next was applied as in the flushing procedure used alone. Both vehicles were driven at speeds less than 5 mph.


Equipment: The MF-MS-MF equipment plus the detergent and a bucket for handcasting.
Personnel: A driver for each of the two vehicles; one man for handcasting the detergent and one supervisor.

Procedure: After the first cursory flushing; the detergent was hand-cast over the test area. Thereacter the procedure was identical with the MF-MS-MF operation.

2.4.2 Roofing Areas

The basic decontamination procedures evaluated on roofing areas

a. Firehosing (FH),
b. Firehosing, Hand Scrubbing, Firehosing (FH-BS-FH)
c. Firehosing, Hand Scrubbing with Detergent, Firehosing (FH-HSD-FH)

A description of the procedures follows:

FH (Fig. 2.11.)

Equipment: The same as for firehosing paved areas except for only one 1-1/2-in. firehose equipped, ‘With a Model. 14 NAP Griswold Fog Nozzle. The pump was adjusted, in this case, to deliver 60 psig at the nozzle. Ladders or scaffolds for access to the roofing areas on existing buildings were required.

Personnel: The number varied, but generally 1 man attended the pump, 1 or 2 handled the hose, 2 directed the 1-1/2-in. nozzle, and at least 1 supervised.

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Procedure: Hosing was started at the back of the roof area or panel, and proceeded across and down to the edge of the area. The nozzle operators experienced no great difficulty in working on the roof areas.

On the tar and gravel areas, which were essentially flat, the firehosing started at the edge of the roof and the hosers walked backward toward the center While aiming the nozzle toward the roof’s edge. This kept the loosened gravel from becomming windrowed and blocking the water runoff. The rate of advance was determined visually, the work progressing as fast as the area appeared to be cleaned.

FH-HS-FH (Fig. 2.12)

Equipment: The FE equipment as before plus 4 long-handled scrub brushes.

Personnel: One man attended the pump, 1 to 2 the hose, and 2 the nozzle; 3 to 4 men scrubbed and at least 1 supervised.

Procedure: On the first pass, the firehose team operated as before but at a faster rate. Then the area was scrubbed until it looked clean. The second, clean-up firehosing was at the same rate as for the FH procedure.

FH-HSD-FH (Fig. 2.13)

Equipment: The FH-HS-FH equipment plus a small bucket for handcasting the detergent.

Personnel: Those for FH-HS-FH plus 1 man for dispersing the detergent.

Procedure: The procedure is the same as for FH-HIS-FH except that the detergent was applied to the surface immediately after the initial firehosing.


Radiological-safety monitors were present during the preparation and dispersal of the synthetic fallout material and during decontamination. A rad-safe courier accompanied each shipment of La140 from Arco, Idaho, to Camp Stoneman. Complete details of the rad-safe support are described in Reference 12.
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Fig. 2.1.3 Hand Scrubbing, ‘With Detergent” Root Area


The California Forest and Range Experimental Station, U.S. Forest Service, Berkeley, Calif., and the Quartermaster Research and Development Center, Natick Mass., conducted experiments during the operation. theri interest primarily was to take advantage of the availability of synthetic fallout, technical monitoring, and rad-safe facilities.
The California Forest and Range Experimental Station conducted
preliminary experiments on teh decontamination of overgrown land areas by burning. A report 13 has been issued on this phase of the operation.
The Quartermaster Research and Development Center conducted experiments to determine the extent of contamination of field food-preparation equipment, food distribution equipment, and eating utensils, and to attempt various methods of decontamination.

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Chapter 3

In comparing the manual procedures,” it is seen that more effort was expended in the procedures involving hand scrubbing with and without detergent than in the straight firehosing procedure. The resulting final levels were, in most instances, lower when the scrubbing procedures were used. One effect of the use of detergent with hand scrubbing, besides its ability to remove dirt and grease films from surfaces, was its action as a visible indicator. The foaming action provided a visual indicator showing areas scrubbed an those missed. This was especially true on the asphaltic concrete area contaminated with slurry synthetic fallout at the lower mass level. In this test forthe same amount of effort expended, the addition of detergent increased the effectiveness by a factor of 6.

As in the case of the addition of hand scrubbing to the firehosing procedure, “the addition of motorized scrubbing to the motorized flushing procedure required an increase of effort. This increase, however, did not produce a significant increase in effectiveness at the higher mass levels. This may have been due to the manner in which the motorized sweeper was utilized. The broom on the sweeper did not contact the surface evenly and streaks of visible material were left on the surface after the sweeper passed over the area. An increase in effectiveness was noted at the lower mass levels.

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50th Chemical Service Platoon Decontamination Truck (Type M3A3)
As part of its basic equipment, the 50th Chemical Service Platoon, which was assigned as a supporting force, had several high pressure pumps mounted on 2-1/2-ton trucks (designed for ABC decontamination) during the Camp Stoneman tests. To evaluate their ability to remove synthetic fallout, tests were conducted on portland cement concrete and asphaltic concrete test areas contaminated with dry and slurry simulant. The results are presented in Tables 3.1 and 3.2. The effectiveness of this procedure was as good as any of the other procedures evaluated. The effort required, however, was considerably greater, due to the limited capability of the equipment to discharge large quantities of water. Each unit had a water capacity of 400 gal and was capable of discharging only 30 to 35 gpm at 300 to 400 psig.

4.1.2 Decontamination Effectiveness on Roofing Materials It is necessary that the roofing decontamination data, presented in the tables of Chapter 3, be qualified so that proper significance is placed upon them.

Each particular test was conducted but once, so that no measure was made of the reproducibility of any specific result. Even so, valid conclusions concerning the order of magnitude of the decontamination effectiveness afforded by the several methods on the test surfaces may be drawn. Initial levels of contamination, as measured, varied widely both from test to test and within individual experiments. Uneven spreading of the fallout simulant, use of an unshielded instrument which was influenced by radiation from adjacent contaminated test areas, and edge effects caused by the geometry of the test area-instrument combination contributed to this wide variation in initial readings.

Final readings differed more than would be expected from the variability of the decontamination itself for several reasons. Bias was introduced by the same geometry situation that influenced the initial readings, in addition to the effect of the roof slope (lower edges were generally less effectively decontaminated than upper ones) and influence from contaminant collected in drains and gutters or washed off onto the ground.

In order to minimize the above-described bias in the test results, it was decided to report only the radiation levels measured at the most central stations on each of the test areas. See Appendix D for location of stations used.

It was assumed that small differences in results of one procedure over another were not significant.
[Note: The report goes on to determine the amount of radiation received by each participant in each activity concluding that based on the personnel standing in a clean area while using the hoses or the brush on the contaminated area that they were not immediately affected by the radiation and they got between 11.4 to 20.1 R. at 10 r/Hr. 10 R/hr is considered an Acute Exposure which increases the risk of cancer and is considered a nuclear accident.

This also does not tell us how much radiation the worker had when he used the lawn spreader to spray the roof with 10,000 rads of radiation.

The problem is further complicated in that they contaminated over half of the base, so they either killed these guys or they had a lot of people involved in the contamination and clean up of the base. Area irradiated in


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