APPENDIX G
Bomb Incident-A Controlled Study
Allan Palmer, M.D.
A bomb, designated as U.S. M41 and described as an antipersonnelfragmentation bomb, exploded when it was dropped accidentally on the concretesurface of dispersal area No. 3 of AAF (Army Air Force) Station 128 atDeenethorpe, England, on 12 June 1944.1 A mission in which aircraft B-17-G No. 42-107210was to have taken part was cancelled. The ground crew of the B-17-G ship,together with the ground crew of another ship, were engaged in unloading theclusters of M41 bombs from the bomb racks. A shackle holding three of the bombsto one end of the support for a cluster of six was loose or broken, and duringthe handing down of the cluster the three bombs fell to the concrete-adistance of approximately 6 feet. One of the bombs exploded, another becamearmed but did not explode, and the third remained unarmed.
The official ordnance report of the accident by the ordnance officer of theEighth Air Force is extracted as follows:
1. Place of accident: AAF Station 128, 401stBombardment Group, located near Deenethorpe, England, Grid reference of field496090.
2. Time of accident: 1535 hours, 12 June 1944.
3. Bombs: One (1) M41 Fragmentation bomb 20 lb in M1A1cluster with AN-M110A1, instantaneous fuse.
4. Condition of bombs: Bombs were "safe,"being unloaded from aircraft on dispersal site #3.
5. Location of bombs: On dispersal site #3 nearbuildings of the 614th Bomber Squadron Technical Supply and derelict farm house.
6. Effects: A. Casualties: Seventeen, of which fivewere killed and four seriously injured.
B. Damage: The bomb bay wing structure and landing gear of a B-17 #107210were damaged. The aircraft is to be salvaged.
7. Group and station to which aircraft belonged: 401stBomber Squadron Group (H), AAF Station 128.
8. Events causing accident: While unloading a clusterof 6 M41 bombs, a clasp holding bombs to carrier (adapter) evidently buckled andbroke, releasing three bombs, one of which detonated on striking concrete.
9. Action: The loose bombs and clusters were clearedaway, dangerous fuse (in one UXB) removed and destroyed. All clusters wereremoved from aircraft.
10. Additional remarks: A. To the best of our knowledgefour men of Armament and Ordnance Sections of the 614th Bomber Squadron 401stBomber Group (H) were working in each side of the bomb bay, two above and two onthe ground on each side, with a number of other men standing around or helpingin various ways. Usually a crew of four will load or unload a ship, but in thiscase men who had finished unloading other ships had come over to help finish thejob on this one. Both outboard racks had been unloaded and apparently crews hadbegun work on the double clustered bombs on the inboard racks. It was at thistime that the explosion occurred, on the left side of the bomb bay. From theinformation available, the double clustered bomb on the top station was beingremoved, although this is not certain. By later comparing lot numbers of bombsand fuses, both loose or partially clustered, it was determined with reasonablecertainty from which cluster the exploded bomb came. There were three intactbombs remaining on the rear of this cluster but, the clasp attached to the stripdesigned to hold the three bombs to the adapter had apparently buckled and hadbroken, evidently releasing the three bombs which fell to the ground, one ofwhich exploded on impact. The nose portion of the fuse on this bomb wasrecovered, proving that the fuse was in an unarmed condition. The adapter was ofthe type used to repair bombs in the U.K. and procured here. There were thus twoequipment malfunctions, the broken clasp on the adapter and the AN-M110A1 nosefuse, which functioned, even though in "safe" condition.
B. One bomb from a cluster, otherthan the one mentioned above, fell and became armed and in a dangerouscondition. The striker head and safety collar were missing from the nose of thefuse. The R.A.F. Bomb Disposal Squad at Bramcote was notified, but they statedthat they were not permitted by the Air Ministry to dispose of U.S. bombs whichhad become dangerous during loading or unloading operations, of A/C on theground. Consequently, the bomb was later safetied by removing and destroying thefuse.
C. The following precautions will be stressed in an effort to prevent any further accidents with this type of bomb:
During normal inspection of cluster for damage or indications of possible failure, they will be completely prepared for subsequent loading. The safety pins will be removed from the clasp and replaced with long pieces of arming wire to facili-
1One of the primary reasons for reporting this incident is to illustrate the type of investigation which should follow all accidents involving U.S. weapons. Under these semicontrolled circumstances, exact information can be collected in regard to (1) type of weapon; (2) number of men exposed, posture, duty, equipment and clothing, and distance from weapon; (3) number of casualties, types and severity of wounds, and extent of hospitalization; (4) recovery of fragments or bullets; and (5) documentation with photographs and X-rays. These unfortunate accidents can then be utilized as biological indicators of the effectiveness of our weapons.-J. C. B.
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tate removal after loading. Safety wires arerequired to be in place during loading. The arming wire will be replaced with a500 lb G.P. bomb arming wire or equivalent, and Farhnestock clips attached.
When clusters are to be unloaded, theprocedure will be started from the top stations and safety wires inserted inclasps before removing bombs from racks. Although this has been requiredprocedure, the job has been so difficult, because of inaccessibility and lack oftime, that it is believed it has not been done consistently. However, thisaccident is considered attributable primarily to malfunctions resulting frompoor equipment designs, rather than the failure to insert the safety wire. Thelatter procedure will serve more certainly to prevent breaking of clusters byinadvertent removal of the arming wire during handling.
D. All casualties wereground force members of the 614th Bomber Squadron 401st Bomber Group (H).
(Signed) JAMES C. DAVID,
Capt., Ord. Dept.,Gp. and Sta. Ord. Officer.
SCENE OF THE INCIDENT
Within a 300-foot radius of the point of impact of the bombthat exploded (fig. 1), there were 24 men, 1 aircraft (B-17-G No. 42-107210), 1pyramidal tent, 1 technical supply nissen hut, 1 brick farm building, and 1bomb-carrying trailer.
FIGURE 1.-Location of men and buildingswithin a 300-foot radius of the point of impact
of bomb.
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Of the 24 men known to be present within a 300-foot radius(table 1), 6 were located just less than the full 300-foot range and wereuninjured, although one of these, S, standing in the doorway of the brickfarmhouse, was struck in the right thigh by a bomb fragment. The missile wasreflected against his pocket knife and became buried in the wooden structure ofthe door. The man furthest from the burst who sustained injury was L, approximately150 feet away. He was walking in the direction of the aircraft and was knockeddown by a fragment that struck his left elbow and fractured the medial condyleof his left humerus.
TABLE 1.-Personnelexposed to explosion of a U.S. 20-pound (M41) fragmentation bomb
Personnel | Distance from burst | Part of body exposed | Protection | Classification | Disposition |
| Feet |
|
|
|
|
A | 21 | Front | None | Killed | Buried |
B | 25 | ...do... | ...do... | ...do... | Do. |
C | 5 | Front (above burst) | ...do... | ...do... | Do. |
D | 8 | Front | ...do... | ...do... | Do. |
E | 30 | Back | ...do... | Died of wounds | Do. |
F | 23 | Front | ...do... | ...do... | Do. |
G | 31 | ...do... | Partial, by left landing gear | Severely injured | Evacuated to Zone of Interior after 57 days. |
H | 28 | ...do... | Head protected by chin turret | ...do... | Zone of Interior after 100 days. |
I | 32 | Back | None | ...do... | Returned to duty after 56 days. |
J | 31 | Front | ...do... | ...do... | Returned to duty after 30 days. |
K | 36 | Left side | Partial, by left landing gear | ...do... | Returned to duty after 42 days. |
L | 150 | Front | None | ...do... | Returned to duty after 23 days. |
M | 6 | Lower limbs (above burst) | ...do... | ...do... | Returned to duty after 29 days. |
N | 5 | Lower limbs (above burst) | Partial, by inboard panel and bomb clusters | ...do... | Returned to duty after 10 days |
O | 29 | Front | Partial, by casualty F. | ...do... | Returned to duty after 27 days. |
P | 23 | Front | Partial, by casualty D. | ...do... | Returned to duty after 35 days. |
Q | 9 | Front (above burst) | Complete, by inboard panel and bomb clusters. | ...do... | Returned to duty. |
R | 40 | Front | Bomb trailer | Uninjured | Do. |
S | 255 | ...do... | Pocket knife | ...do... | Do. |
T,U,V,W, and X | 300 | Unknown | None | ...do... | Do. |
The remaining 17 men were within a 40-foot radius and all butone (R) were killed or injured. Four men were killed instantly and twodied within 24 hours of the time of injury. The other casualties sustainedinjuries of varying severity. The least serious injury was in a casualty (Q) whosuffered a very slight tearing of his left eardrum, resulting in a hemorrhageinto the auditory canal. He was not sent to hospital but was examined and takencare of at the AAF station. This man was standing forward about 9 feet above theburst in the right bomb bay. He was protected from a direct hit by bombfragments by the inboard panel still bearing clusters of the M41 bombs.
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FIGURE 2.-Eighth Air Force ORS battle damagereport on B-17-G No. 42-107210 aircraft.
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832
FIGURE 3.-Continued. C. Damage to bomb baydoors. D. Damage to landing gear.
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The B-17-G aircraft was located with the mengrouped about it as shown in figure 1. Damage to the aircraft is shown in theEighth Air Force ORS (Operational Research Section) battle damage report (fig.2) and in figure 3. The category of damage is given as "E" which, asdiscussed in USSTAF (U.S. Strategic Air Forces) Regulations No. 80-6, 8 May1944, refers to an aircraft damaged beyond economical repair, such as incrashlandings.
The pyramidal tent located 150 feet to thewest of the burst received no hits by bomb fragments. The brick farm building(used as a workshop) diagonally 250 to 300 feet to the southwest was struck byat least 30 high-velocity fragments having a mass estimated to be from 5 to 10gm. Pitting of the brick wall of the building to a depth of 1 inch or moreserved to indicate which fragmentation marks were the result of high-velocityfragments of the estimated weight. Most of the fragmentation marks were between4 and 5 feet above ground level. Some of the marks seemed to be due togroups of smaller fragments. These marks were clustered about a larger anddeeper mark, the clusters covering an area of 25 or 30 square inches. Two largefragment marks were found approximately 12 feet above ground level and severalat a height of 6 to 7 feet. One fragment made a ?-inch hole through a piece ofiron pipe, the walls of which were an eighth of an inch, and came to rest buriedin a wooden door. The pipe was part of some structural framework on the side ofthe brick farm building, and the point at which the building was struck wasexactly 252 feet from the burst, 3 feet above the ground level.
The maximum depth of the bomb crater was 1?inches and was located, as shown in figure 1, in the concrete dispersal area.The fragmentation pattern was assymmetrical, indicating that the bomb struck theconcrete nose first but with its axis deviating from the perpendicular. Thepattern radiated from the crater toward the nose of the aircraft, through an arcof 220?. At the center of the arc, the pattern extended 6 feet. Maximumextensions of the pattern, amounting to 10 feet from the crater, occurred at55? to the right and left of the center. Here the density of strikes wasgreatest. At the extremities of the arc, the pattern extended no more than 3feet from the crater, with density of strikes very slight. From these facts, itwould appear that the inclination of the bomb axis from the perpendicular was inthe direction of the nose of the ship, where the majority of men at work werecongregated. It would appear further that the normal horizontal spray offragments occurred to the left and right of the aircraft as indicated by thefragmentation pattern and the level and distribution of fragmentation marks onthe side wall of the brick farm building. The dispersal of fragments throughoutthe remaining 140? of the arc not represented in the concrete fragmentationpattern appears to have been upward and slightly backward through the wings ofthe aircraft. The total area of wing surface hit by bomb fragments was found, byplanimeter measurement on a scale drawing of the aircraft, to be 27 square feet.In this surface area, there were 180 penetrations or an average of nearly 7strikes per square foot at distances varying from 5 to 40 feet from the burst.
It is of interest to note from theconfiguration of the fragmentation pattern on the concrete that with theexception of casualty A all the rest of the casualties on the ground wereproduced by bomb fragments, the velocity of which may have been considerablyreduced because of the retardation produced by the richochetting of thefragments against the concrete surface.
The technical supply hut south of the burst(fig. 1) received one through-and-through, hit on the convexity of the roofstructures and three hits on its front about 3 feet above ground level. Thebomb-carrying trailer present at the time of the accident was not available forinspection.
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DESCRIPTION AND PERFORMANCE OF U.S. 20-POUND FRAGMENTATIONBOMB
Construction
The M41 fragmentation bomb (fig. 4) has acharge-weight ratio of approximately 15 percent. Details of its construction arefurnished by Prof. Marston Morse in his statement communicated to the WoundBallistic Conference on 27 April 1944. The overall length of the bomb is 22.2inches and its diameter about 4 inches. A long rod of square wire 0.44 x 0.44inch is tightly wrapped about a light cylindrical casing 0.11 inch thick to formthe main body of the bomb. The cylinder is filled with TNT or other explosives.The ends are sealed with steel plugs. The nose plug contains a cavity for aninstantaneous fuse, and the tail plug has a threaded hole to take the tail fins.
FIGURE 4.-U.S. 20-pound (M41) fragmentationbomb.
The bomb is normally clustered into the M1A1 cluster of sixbombs (fig. 5). The following loads, prescribed in USSTAF Ordnance MemorandumNo. 3-54, 16 March 1944, were carried by aircraft in use by the U.S. Air Forces:
Aircraft: | Load1 |
| B-17 | 38-42 |
| B-24 | 52 |
| B-26 | 30 |
| B-25 | 30 |
In clusters of 6 bombs.
When an M41 bomb falls, 250 revolutions of the propellerlikeblade, on the nose of the bomb, are required before the bomb is armed. Thisprocess permits the collarlike safety block located just ahead of the propellerto fall away, which in turn permits the striker head to be driven into the fuseupon impact. As stated in the official ordnance report (p. 827) and
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FIGURE 5.-M1A1 clusters of U.S. 20-pound(M41) fragmentation bombs
FIGURE 6.-Defective fuze of M41 fragmentationbomb, showing safety block in place.
as shown in figure 6, the safety block on the fuze of the bombthat exploded in the incident being reported was in place. Thus, the fusefunctioned even though in a "safe" condition.
Fragmentation
The effect of wrapping the bomb cylinder with square wire isto produce a large number of fragments, each of which is a piece of rod 0.4 inchto 1 inch long (fig. 7). These fragments are much more effective per pound ofmetal than the usual long, narrow shell fragments.
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In static and drop trials, the number offragments recovered is approximately 1,000 for the TNT loading and is from 40 to60 percent greater with ednatol or RDX Compound B loadings. For the TNT loading,75 percent of the fragments exceed 2.25 gm., 50 percent exceed 4.0 gm., and 25percent exceed 7.0 gm. in weight. In static and drop trials at the ordnanceproving grounds at Millersford, England, quoted by Zuckerman, the number offragments heavier than 1.3 gm. was 883. Fragments of less than 1.3 gm. were notcounted. Zuckerman reports the actual recovery of 319 M41 bomb fragments,weighing more than 1.3 gm. each, from the roof of the Bocca di Falco AirfieldBuilding, Palermo, Sicily, where a single M41 bomb had burst. The total weightof the fragments was 3.65 pounds, or about 25 percent of the potentialfragmenting metal. Morse gives the figure of 1,274 as being the total number offragments weighing more than 0.25 gm. each from one M41 bomb and, for comparisonwith the ordnance trials at Millersford, 884 fragments weighing more than 1.3grams.
The initial velocity of M41 bomb fragments hasbeen reported (Eighth Air Force Ordnance Memorandum No. 3-17, 18 Sept. 1943) tobe as high as 4,000-5,000 f.p.s. However, the mean velocity of fragments heavierthan 1.3 gm. measured at the Millersford trials was 2,890 f.p.s. over a distanceof from 0 to 10 feet, and Morse gives the average velocity at 20 feet for allfragments exceeding 0.24 gm. in weight as 2,810 f.p.s. He states further thatfor ednatol loading the initial velocity is 3,000 f.p.s. and for an RDXComposition B loading, 3,280 f.p.s. The Sachs-Bidelman Memorandum Report No. 267from the Aberdeen Proving Ground follows closely if it is not actually the sameas Professor Morse's statement of velocities of M41 bomb fragments for thethree different loadings given.
Effective Range
Because of its cylindrical construction, thezone of maximum fragment density for an M41 bomb is extremely narrow, beingapproximately not more than 3? above the equatorial
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plane and then only when it bursts with itsaxis vertical. Slight deviations of the bomb from a vertical position materiallyaffect its effectiveness. Ordnance Memorandum No. 3-17, 18 September 1943, givesas criteria for effectiveness against personnel a minimum of two fragment hitsper individual. Since a man when standing erect is regarded as presenting anaverage target area of 4.2 square feet, this corresponds to a minimum fragmentdensity of approximately 0.5 fragments per square foot for effectiveness. Fromthis, it is estimated that the effective range for an M41 bomb exploding in thevertical position is 50 feet. Approximate calculations for angles of impact at10? and 20? from the vertical give the following figures:
Angle of impact from the vertical position (degree) | Radius of effective range (feet) | |
Forward | Rear | |
0 | 50 | 50 |
10 | 33 | 8 |
20 | 13 | 3 |
The findings at the scene of the accidentsuggest that the angle of impact of the bomb was at least 45?. This assumptionwas made because it was found that a narrow zone of maximum density offragmentation occurred against the undersurface of the wings of the damagedaircraft at a point slightly more above than to the rear of the point of impact.
The decrease in effective range forward, for abomb striking at an angle, obviously does not hold for a bomb falling a shortdistance on a concrete surface.
STUDY OF CASUALTIES
An estimate of the risk of an individual toinjury by bomb fragments may be made from the data in table 1. The factors to betaken into account are as follows:
1. Surface area of the body exposed, less areaprotected by parts of planes, objects, or other individuals.
2. Distance from burst.
3. Direction of fragment spray.
The mean projected area of the body and itsparts, as recorded by Krohn working with Burns and Zuckerman,2enables one to estimate the approximate surface areas of individuals exposed toinjury. From these data, table 2 was compiled. It is shown that, of the sevenindividuals within 30 feet of the burst and without any appreciable protection,six were killed or died as a result of wounds and the seventh injured soseverely that he required more than 3 months' hospitalization and waspermanently lost from the service. Two individuals, M and N, within15 feet of the burst and with only their lower extremities exposed, were out ofthe line of spray of effective bomb fragments and sustained only slightinjuries. Two others, O and P, within 30 feet of the burst were inthe line of spray but because they were almost completely protected by otherindividuals were only slightly injured. The four remaining individuals, I, J,K, and L, who were further distant than 30 feet from the burst andwho received injuries, required hospitalization for periods averaging longerthan 5 weeks. Table 3 shows the casualty rates pertaining to the 24 men known tobe present at the scene of the incident.
2Burns, B. D., and Zuckerman, S.: The Wounding Power of Small Bomb and Shell Fragments. R. C. No. 350 of the Research and Experiments Department of the Ministry of Home Security.
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TABLE 2.-Observed hits by M41 bombfragments sustained by casualties at various distances fromburst
["Area" refers to the approximate bodysurface area exposed to bomb fragments by each casualty in square feet]
Casualty | Distance (feet) from point of burst | |||||||||
0-15 | 15-30 | 30-45 | 150 | >250 | ||||||
Hits | Area | Hits | Area | Hits | Area | Hits | Area | Hits | Area | |
A | --- | --- | 19 | 4.2 | --- | --- | --- | --- | --- | --- |
B | --- | --- | 15 | 4.2 | --- | --- | --- | --- | --- | --- |
C | 44 | 4.2 | --- | --- | --- | --- | --- | --- | --- | --- |
D | 10 | 4.2 | --- | --- | --- | --- | --- | --- | --- | --- |
E | --- | --- | 8 | 4.2 | --- | --- | --- | --- | --- | --- |
F | --- | --- | 18 | 4.2 | --- | --- | --- | --- | --- | --- |
G | --- | --- | --- | --- | 2 | 1 | --- | --- | --- | --- |
H | --- | --- | 11 | 3.7 | --- | --- | --- | --- | --- | --- |
I | --- | --- | --- | --- | 12 | 4.2 | --- | --- | --- | --- |
J | --- | --- | --- | --- | 3 | 4.2 | --- | --- | --- | --- |
K | --- | --- | --- | --- | 1 | 1 | --- | --- | --- | --- |
L | --- | --- | --- | --- | --- | --- | 1 | 4.2 | --- | --- |
M | 10 | 1.65 | --- | --- | --- | --- | --- | --- | --- | --- |
N | 4 | 1.65 | --- | --- | --- | --- | --- | --- | --- | --- |
O | --- | --- | 3 | 1 | --- | --- | --- | --- | --- | --- |
P | --- | --- | 3 | 1 | --- | --- | --- | --- | --- | --- |
S | --- | --- | --- | --- | --- | --- | --- | --- | 1 | 4.2 |
| 68 | 11.7 | 77 | 22.5 | 18 | 10.4 | 1 | 4.2 | 1 | 4.2 |
Observed hits per square foot surface area | 5.8 | 3.4 | 1.7 | 0.2 | 0.2 | |||||
Expected hits per individual when exposed area is 4.2 square feet | 24 | 14 | 7 | 1 | 1 | |||||
TABLE 3.-Casualty rates of 24 men exposedto bomb fragments
Distance from burst | Number of men exposed | Casualties (killed or wounded) | |
Number | Percent | ||
Feet: |
|
|
|
| 0-15 | 5 | 5 | 100.0 |
| 15-30 | 7 | 7 | 100.0 |
| 30-45 | 5 | 4 | 83.0 |
| >45 | 7 | 1 | 14.0 |
Figure 8 shows graphically the number of hits per square footof body surface exposed at varying distances from the burst. These findings showa desirable distribution of fragments for antipersonnel effect and agree closelywith the fragment density reported by Zuckerman in his communication from Sicilyon the performance of the U.S. M41 bombs against grounded aircraft. It is ofinterest to note again that all of the casualties standing on the pavementtoward the nose end of the aircraft, ahead of the burst, were presumably struckby fragments ricochetting on the concrete dispersal area.3Thus, in general, the
3At a later date, 28 September 1944, the writer recommended by letter, Special Incident Report, to Col. Elliott C. Cutler, MC, Chief Surgical Consultant, ETOUSA, that " * * * as a safety measure, some thought might be given by the Air Force to the loading and unloading of bombs * * * into and from aircraft on a specially prepared or selected surface."-J. C. B.
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distribution of ricochetted fragments against personnel in this incidentclosely approximated the distribution of fragments directly striking the wingsof the aircraft damaged by the same burst. Further, the estimated fragmentdensity at 50 feet in this incident was approximately three times as great asthe estimate given in Ordnance Memorandum No. 3-17.
REGIONAL DISTRIBUTION OF WOUNDS
Table 4 shows the regional incidence of wounds in the 17 casualties. Onlyfour individuals sustained single wounds, one of which was casualty Q whohad only a slight tearing
TABLE 4.-Distribution of 163 single andmultiple wounds in 17 (11 wounded, 6 killed) casualties,by anatomic location
Anatomic location | Single wound | Multiple wounds | Total wounds | ||||
2 regions involved | 3 regions involved | 4 regions involved | 5 regions involved | Number | Percent | ||
Head | 2 | 1 | 3 | 1 | 5 | 12 | 7.4 |
Neck | --- | --- | 1 | --- | 3 | 4 | 2.4 |
Chest | 1 | 1 | 6 | 10 | 29 | 47 | 28.8 |
Abdomen and scrotum | --- | --- | 4 | 1 | 1 | 6 | 3.7 |
Upper limb | 1 | 1 | 8 | 7 | 18 | 35 | 21.5 |
Lower limb | --- | 6 | 31 | 15 | 7 | 59 | 36.2 |
| 4 | 9 | 53 | 34 | 63 | 163 | 100.0 |
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of one eardrum. The greatest number of hits was 44, receivedby casualty C (killed). He was hit in five regions of the body includingboth upper and both lower limbs. This is a very conservative estimate of thenumber of hits since many of the wounds were so extensive that it was impossibleto determine the number of bomb fragments that may have passed through thetissues.
The 28.8 percent incidence of thoracic wounds in this incidentis greater than that reported in most casualty surveys of large samples and isobviously due to the inclusion of the killed with the wounded.
Table 5 shows the incidence and distribution of fractures.Four casualties sustained a total of 10 traumatic amputations of limbs or partsof limbs. These are included in the number of fractures. Of the 17 casualties,13 sustained fractures and of these 10 had more than one.
TABLE 5.-Distribution of 46 fractures(including amputations) in 17 casualties, by anatomic location
Anatomic location | Number of casualties with fractures | Total number of fractures (including amputations) |
Head | 6 | 8 |
Chest | 4 | 16 |
Abdomen | --- | --- |
Upper limb | 7 | 11 |
Lower limb | 6 | 11 |
Casualty B (killed) presented the most extensivefracture of the skull, in addition to fractures of one upper and one lower limb.Besides comminution of the skull at the points of entrance and exit of a bombfragment, all the bones of the skull and face, except the mandible, weredisarticulated at their suture lines. The brain stem had been transected, andthe entire substance of both cerebral hemispheres was macerated. The skull andbrain appeared to have momentarily undergone an explosivelike expansion andcavitation. The missile stopped subcutaneously in the back of the neck aftermaking its exit from the skull through the occipital bone.
Of the six dead, four had single or multiple penetratingwounds of the chest and one the penetrating wound of the skull described in thepreceding paragraph. The sixth casualty, D, although he did not have apenetrating wound of the skull or other body cavities, did sustain traumaticamputations of his lower limbs in three places, multiple perforating wounds ofhis upper extremities, and superficial chest wounds. He presumably died almostinstantly from shock and hemorrhage. His eardrums were intact.
The only evidence of damage by blast was the slight tearing ofan eardrum in casualty Q who was within 10 feet of the burst but completelyprotected from a direct hit by the intervening inboard panel and clusters ofbomb still in place. The eardrums of others, closer to the burst, were intact.
SIZE OF FRAGMENTS CAUSING WOUNDS
The sizes of fragments responsible for woundswere determined by weighing those recovered from the dead and estimating theweights of others from their X-ray silhouettes. In the case of the latter, thefragments were estimated in grams from their linear dimensions. A large seriesof X-rays of fragments of known weight were available as a standard. Table 6summarizes the information obtained on this point and also gives the distancesfrom the burst at which the casualties were struck.
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TABLE 6.-Size of fragments recovered fromcasualties struck at several distances from point ofburst
Category of casualty and distance (feet) from point of burst | Number of casualties | Fragment size (grams) | Total number of fragments | ||||
0.001 to 0.05 | 0.05 to 0.25 | 0.25 to 1.0 | 1 to 5 | >5 | |||
Wounded: |
|
|
|
|
|
|
|
| 0-15 | 1 | 6 | --- | 2 | --- | --- | 8 |
| 15-30 | 3 | 2 | 7 | 6 | 1 | --- | 16 |
| 30-45 | 3 | --- | 6 | 9 | 1 | --- | 16 |
| 7 | 8 | 13 | 17 | 2 | --- | 40 |
Killed: |
|
|
|
|
|
|
|
| 0-15 | 1 | --- | 1 | 2 | --- | --- | 3 |
| 15-30 | 4 | --- | 2 | 1 | 7 | 1 | 11 |
| 5 | --- | 3 | 3 | 7 | 1 | 14 |
In all, there were 40 bomb fragments in 7 ofthe wounded that could be seen in X-ray films and 14 fragments recovered from 5of the killed casualties. This represents a recovery of 90 percent of fragmentscausing wounds in the living but only 13.4 percent of fragments causing woundsin the dead.
The average weight of fragments causing woundsin the living casualties was 0.43?0.65 gm., whereas the average weight offragments recovered from the dead was 1.86?1.82 gm. The difference in meanweight of fragments causing wounds in the killed and in the wounded in thisincident involving a small number of people was found to be 1.43?0.48 gm. (t=2.98,P less than 0.01). The difference in the mean weights is statisticallysignificant. It may be assumed that the mean weight of fragments causing woundsin the dead is considerably greater than shown in the sample, since, by far, themajority of them caused through-and-through wounds and were not retained orrecovered. On the other hand, the X-rays of fragments in the wounded that wereavailable for study represent practically all of the fragments responsible forthe wounds in the living. From the average fragment weight found in the X-raysof the living casualties, it may be said that M41 bomb fragments of less than 1gm. in weight are relatively incapable of producing fatal injuries but aredefinitely incapacitating in their effect.
Bomb fragmentation trials in which the screenshave failed to recover fragments weighing less than one twenty-fifth of an ouncelack ballistic data on fragments of such small size. However, the wounding powerof small fragments has been discussed at great length by Burns and Zuckerman.Their conclusion that within the 100-foot radius of a bomb burst 50 percent ofthe wounding power of a 20-pound fragmentation bomb is due to fragments weighingless than one twenty-fifth of an ounce is well supported by the findings in thisincident.
