ee RADIOLOGICAL CLEANUP OF ENEWETAK ATOLL the western tip of Enjebi.?! The location of the HEUS operation is shown in Figure 1-58. The engine started operating normally but, after a short time, it exhibited uncontrolled burning which resulted in destruction of the eee ee 1968, resulted in a high-order detonation which scattered propellant over ee oe 60 Description and History: 1526-1972 61 after decontamination showed the cleaning operation to be “‘quite successful” or “‘reasonably successful,’’ the beryllium content of the soil being, in many cases, less than the contamination that was present before the second test.?3 Beryllium is toxic to man when inhaled and lodged in the lungs. The threshold level for such toxicity was defined in 197] as 0.01 microgram per cubic meter of atmospheric air.?4 The area was rechecked in 197! by AEC contractor personnel. Soil sample analysis showed no surface att \ contamination greater than 0.05 microgram of beryllium per gram of dry an oni a soil. It was believed that decontamination and erosion of the western tip of Enjebi had reduced contamination such that there would be no problem with beryllium on the surface. OCEAN EASY GZ Pe HARDTACK STATION 1312 X-RAY GZ a a / <~ COAX CABLE RUN ee HEUS ROCKET LAUNCH PAD 1968 LAGOON FIGURE 1-58. PROJECT HEUS, ENJEBI. engine, spalling of the concrete blockhouse to which it was attached, and the spreading of beryllium metal and oxides over a wide area in a nonuniform manner. After wetting the area thoroughly, a decontamination crew scraped dirt from the surface inside a circle of 100 feet radius. The dirt was buried in the crater resulting from the explosion. In addition to soil contamination, some beryllium was plated on the surface of a concrete blockhouse. No attempt was made at thal time to determine the exactlocation or extent of contamination. An investigation was made in May 1969 and, although the area was indicated to be safe without protective clothing or breathing apparatus, the results also were > contamination pattern. A second firing conducted in January 1970 was successful and did not result in an explosion. The U.S. Air Force Environmental Health . Laboratory took soil samples before, during, and after firing. The results were published in the Laboratory’s Report Number 71M-2.92 Sampling