Memo to Files, Subject: Conference with Danish Representatives in Pentagon, March 18-19, to Follow Up on Broken Arrow/Crested Ice Project, Thule Base, Greenland (January 21, 1968)

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UNITED STATES GOVERNMENT INFORMATION THRU: John R. Totter, Director Division of Biology and Division of Biology and Medicine SUBJECT: CONFERENCE WITH DANISH REPRESENTATIVES IN PENTAGON, MARCH 18-19, TO FOLLOW UP ON BROKEN ARROW/CRESTED ICE PROJECT, THULE BASE, GREENLAND The official list of participants is given on Attachment I. A number of people on Dr. Walske’s staff participated at one time or another. Mr. Hans Koch and Dr. Walske shared the chair as they did at Copenhagen; everything moved effortlessly with a great deal of cordiality. Mr. Koch indicated that the Danish government had appointed the following committee with himself as chairman to coordinate all efforts to evalu ate the situation at Thule and undertake whatever further measures are understanding signed by Mr. Koch therefore has an official connotation. At the first session on March 18, General Hunziker, Dr. Gjdrup, and Dr. Langham reported on progress in the cleanup and on data obtained since the Copenhagen meeting this time last month. With the advent of daylight. General Hunziker has been able to put large numbers of men on the ice to carry out shoulder-to-shoulder search of the ice for pieces of metal. The weather has held good and now the ice is considered to have been satisfactorily cleared of metal. He was also able to get moderately heavy road equipment onto the ice to scrape up the heavily contaminated area (defined by IRL’s Fidler meters) corresponding in general to the 500 x 2000 foot blackened-streak and roughly the southern half of the cracked ice area. The scrapings, about 230,000 cubic feet, have been transported to the shore and stored in 65 empty steel tanks; this material is still frozen. The blackened area is no longer discernable. Surface surveys suggest that possibly 10 to 100 gallons of JP-4 fuel and 350 grams of ^"Pu are still left in the ice. If 30% of this Pu.remains suspended within the JP-4 layer, something like'100 grams of Pu might eventually,spread on the shoreline; however, if agitation breaks down 80% of the emulsion, then.perhaps only 20 grams would reach the shore. In any case, General Hunziker proposes to patrol the shores for metal, pieces of the f . official use only buy US. Savings Bonds btgularij on thy Payroll Savings Plan

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c COFFICIAL USE ONLY airplane, oil, and contamination. While he considers his work largely to be completed, there are still incomplete aspects such as work by the Geodetic survey, current measurements in the bay (it is about three miles/hour on the bottom beneath the crash point), storing the collected snow and ice under controlled conditions, arranging for eventual transport of all con Some 186 cores have been taken from the ice according to a specific pattern which concentrated on the black streak and the cracked ice area. The radioactivity is associated with the carbon-oil layer, although some black areas have distinctly lower levels of Pu than others. Since layers of activity are found at odd angles and positions in the vertical cores from the cracked area, it is reasoned that the ice in this area must have been fractured, blocks upended and hurled about whereupon they froze again in odd angles and positions. As of March 1, 83% of the total Pu on the ice, as estimated from contour lines defined by the Fidler meter, had been removed; if only the black streak area and the southern half of the cracked ice area are considered then about 937« has been removed. The point is that the jumble of ice blocks in the northern half of the cracked ice area has prevented use of the scraper equip ment. Not all the contamination is on the surface of the ice in this area, but no JP-4 or Pu has been found On the parts of the ice cores in contact with the sea water. The highest levels on the meters observed in the earliest surveys were in the range of 450 to 500 mg/m , the highest residual value now is about 200 mg/m^ with most being 5 mg/m^ or less. Dr. Gj^rup collected 121 samples of snow or earth from selected points downwind of the impact and fire column and from the adjacent coast lines or islands where birds or seals might be found. (See map on file and data.) His values range from zero to 3.8 pgm/m^ with an average of 0.4 pg/m . The total cumulative amount 6f Pu for the ice surfaces surrounding black streak and impact comes to about 10 curies;- the highest concentrations were found on the south shore near Narssarsuk. If there had been people at Narssarsuk, the maximal inhaled amount of Pu would have been about 0.05 pc. Other samples collected up to 10 to 15 km downwind from the streak, to the west in the direction of the open water in Baffin Strait, showed very low amounts of Pu; this activity could be the result of drifting snow or the dispersion created by the fire column, but the former mechanism seems more likely. These Pu levels, however, are close to those resulting from ___ deposition from weapons tests. Langham has analyzed only 20 snow samples but his data agree with Gj^rup's. Both find a tendency for higher levels to be on Saunders Island. They agree within a factor of 10; they considered this to be very good in view of the statistics of sample collection. OFFICIAL USE ONLY.

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Gjlirup found only trace amounts of Pu (1.5 pCi/gm) in sea water collected from 9 points along the bottbm (see map on file). Two showed positive values, 0.0016 and 0.00016 ugm/liter, but contamination is suspected. Snails and sea worms from tne bottom were negative for Pu and plankton showed trace amounts. A sledge dog used on the ice and killed in a fight had 0.001 pCi/gm in the liver and 0.3 pCi total activity in its feces; the lung had none. Two foxes showed 1 pCi and 100 pCi respectively in the total gut contents, but nothing in the lungs. Fitzpatrick reported that the nasal swabs and urines of men working on the ice were negative for Pu. Langham then described his reconstruction of what must have taken place as the plane came in. His concept was based on the ice cores mentioned above and on infrared and other kinds of photographs reprocessed to get maximum contrast. These made it evident that the cracked ice area is circular abd about 650 feet in diameter. The northern half has a much more uneven surface as a result of ice blocks frozen into various odd positions. This cracked ice area did not seem to be 650 feet in diameter when I walked over it in all directions because only the above blocks of ice about 150 feet in diameter could be identified as abnormal by a man on foot. But the photo graphs brought out clearly the concentric circular fracture lines that must have refrozen very quickly. There is also clear photographic evidence of a linear streak crossing this cracked area and Langham postulated that if the plane came in at a 15° tangent to the ice with the left wing tip 60° from the horizontal, he then could account for the pattern of break-up and scattering of fuel and engine parts just prior to the contact of the nose with the ice that set off- the high explosive in the weapons. _ The high explosive of the weapons detonated beneath the main fuel tanks „ and hence the amount of fuel in the center of the cracked ice area is minimal. The very high explosive force of the weapons would account for the reticular arrangement of fracture lines and distorted ice blocks. He also postulated that one weapon exploded first and its shock wave then set off the other three. It seems likely that the explosion disintegrated the Pu and alloy, and surrounded as they were by fuel tanks, etc., this metal ought to be impacted on and into the surfaces of one side of many, but not all, pieces of wreckage metal; this is what was found. The JP-4 fuel seems to have played a special role in the distribution of the Pu. First, it seems to have provided a filter or catchment for Pu that otherwise did not impact onto some other stlrface. Second, the burning fuel was the means of dispersal-dilution of Pu over a fairly large number of square kilometers beyond the immediate area of the crash.- — Probably 707. of the fuel burned. And finally, the remaining unburned fuel by virtue of its surface tension properties has continued to influence the distribution of the Pu and other debris. By its coating action the fuel has caused (helped?) Pu to adhere to bits of metal, rubber, nylon, OFFICIAL USE ONLY

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c OFFICIAL USE ONLY plastic, fiberglass, carbon, etc. These do adhere to one another, and they probably minimized the distribution of the Pu over the surface of the ice. Where sufficient residual carbon mixed with this debris there resulted the black streak or "scar"; without the carbon a slightly discolored, unnatural crinkly sort of "ice" formed in this -15° to -40° When such areas are removed, by scraping or by cores, and allowed to melt, the JP-4 floats to the surface bringing with it the above small bits of stuff and most of the Pu. It is not a true emulsifying agent because shaking will cause much of the stuff to settle out, especially the larger bits. But in general the fuel does tend to segregate the Pu (really Pu02) away from the water. In general, 70 to 75% of the Pu will settle out after a time. Track counts by autoradiography of the fines recovered from this semi-emulsion gave mean diameters for the Pu particles of 2 ^ with range of 0.1 y to 100 y. The Danes had also done this and they were very pleased to have arrived at; the same numbers. Some pieces of the wreckage with adherent Pu lost about 507p of their Pu when merely dunked in sea water two or three times. For the most part, however, the curve of removal resembled a Langmuir isotherm. Eighty percent was released from aluminum after some 40 hours in sea water agitated gently so as to simulate wave motion; only 30% was released from steel surfaces in 40 hours. The gradual but steady release of Pu assures that high concentrations will not develop locally from metal that may get into the bay and that the metal will eventually be no Langham then gave some estimates which the Danes carefully noted, trans lated into the units they use, and agreed to with evident pleasure: 1. On the basis of cores, there are 300 to 350 gms of Pu (l^to 2^1. curies); in the cracked ice area, mostly in its central parts. Now that the streak and southern part of the area has been scraped, the residuum is in the northern half of the circle where the. tumbled blocks are. (Danish estimate was 320 grams.) 2. On the basis of cores and the Fidler meter, there were v^abowt 3190 gms (200 curies) of Pu inside the blackened. '-7' area; all but 17. (31 grams, 2 curies) has been removed. (The Danes had estimated IdOtTgrams but agreed with our figures and further said the residuum was a negligible' amount. They indicated they would be happy with this residuum if they could be sure there were no small, local, very hot spots left on the ice.) The accuracy of the above figures depends on the calibration of the Fidler meter and the contour lines. It was agreed that the figure of 3180 + 20% (3700 to 2500) gms is reasonable. OFFICIAL USE ONLY

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OFFICIAL USE ONLY 3. These numbers fall short of the theoretical amount of Pu in the four weapons. Where is the rest?1 Some must be on the airplane metal now being packaged for shipment to the United States for burial. There will be no attempt to recover this. Some has been spread far and wide by the fire column and/or wind-drifted snow. Some may have gotten into the bay at the time of explosion, either directly or by attachment to pieces of plane which sank to the bottom. Some has been recovered directly. It appears unlikely that we shall ever get a precise inventory. Mr. Olson (Lawrence Radiation Laboratory) said he had melted some cores in garbage cans at Thule. He found that 30% of the Pu floats, but this reduces to about 18% with time. However, the fraction which floats is proportional to the amount of "gunk" and carbon present. The Danes Mr. Gj^rup (Danish Atomic Energy Commission), as noted above, has made extensive samplings of cores, snow and earth for ^-^Pu and ^H. He reported that if a sample from the crushed area had no Pu, it also had no ^H. Where the ice had a clean, hard surface, there was no ^H--"the vast majority of the ^H has been taken away by the clean-up procedure." The concentration in the streak area after clean-up was in the range of 10“5 ^ci/cc. He estimated that there may have been 3000 Ci of in the black streak, and 10 Ci in the cracked area. Possibly 330 Ci are left on the ice. /The MPC for for industrial workers over a 40 hour week value of one-thirtieth of 0.03 Ci/mJ for intake of tritium in water by the general population oyer the 1.68 hour week. One gram 3h =9.8x103 Ci There was general agreement on our side that Gjorup's figures for ^H He then presented and discussed the data which he had developed from snow samples collected on the shore, on the islands, and on wide traverses away from the streak (y.£.). These data and the map are on file. Most were below 1 pCi/cm^ (0.01 pCi/nP); the highest value, 40 pCi/cnr of Pu (0.4 pCi/m^), was south of the streak close to the shore and in general the higher values were to the west and south as might be expected from the prevailing winds blowing snow westward and southward. The islands where the birds nest were low or zero. Narssarsuk on the south coast and back into its ravine seemed to have an average level higher than the rest. He estimated that there might be 10 curies spread out on the ice and land exclusive of tjie. streak. There was no alj>ha activity in the lake from which the Base water supply is taken. /16 curies of *^Pu * OFFICIAL USE ONLY

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C OFFICIAL USE ONLY In the afternoon a number of subjects of 9 technical or logistic nature were discussed. There were no difficulties in reaching agreements, which next day, Tuesday, became' items on the "Gentlemen's Agreement" document. Attachment III. For example. General Hunziker noted it was easy to decontaminate completely the trucks and heavy snow removal equipment, but it was hard to remove the Pu that was embedded in small cuts on …