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Strategic Air Attack on the German Powder, Explosives, and Propellants Industry

The Versailles treaty scaled down Germany's powder and explosives industry to about 6 percent of its World War I size. Its maximum World War I production had been 12,000 metric tons of powder and 20,000 metric tons of explosives a month - about 55-60 percent of World War II output. After the war three powder plants (at Reinsdorf, Haslock, and Rottweil) and three explosives plants (at Kruemmel, Doemitz, and Schlebusch) were permitted to make a limited amount of military explosives, but most of the nitrocellulose factories turned to making other commodities, such as celluloid plastics, films, rayon, sausage casings, lacquers.

The plants were small, employed few people, required virtually no imports, and were an important part of Germany's economy. The leading concern was Dynamit A. G. (DAG), dominant after a series of inter-bellum amalgmations with I.G. Farbenindustrie A.G. Next in importance was Westfalische Anhaltische Sprengstoff A.G. (WASAG) and its subsidiaries. Other companies were Wolff and Company A.G. and Lignose Sprengstoff Werke.

Secret Preparations for War

Captured munitions and powder charges indicate that Germany began expanding production and accumulating explosives for World War II in 1933. At first her factories produced single-base nitrocellulose propellants, which could be made without building complex new nitroglycerin plants. But soon facilities were created for producing double-base, solventless propellants, and existing industrial-explosives plants greatly increased their production of TNT.

Montan Industriewerke G.m.b.H., controlled by the Army Weapons Office, had been formed in 1932 to co-ordinate these secret preparations for war. Since the expansion in powder and explosives plants which ensued went far beyond any civilian needs, the government provided the money and determined the policies. Montan built the plants and leased them to DAG, WASAG, and Wolff. These firms created subsidiaries to operate the plants and supplied them with technical men and supervisors. Raw materials were provided by the chemical industry and by new plants built by another government-owned corporation, WIFO. A powder and explosives committee headed by. Dr. Sarrazin took charge of co-ordinating production and pooling technical information among the plants. (A chart showing the organization of the industry appears in the Appendix as Figure 32.)

The first step was to enlarge existing plants and rebuild and re-equip the unused World War I plants. But as early as 1934, plans were being drawn for secret new explosives factories, under the code name Wiese, and the first of them, at Geusen, had its initial section completed in October, 1935.

In 1936, a secret schnell (quick) plan for explosives expansion was launched, and 6,000 tons of steel per month were allocated to it. Thereafter expansion proceeded rapidly. Plans were revised upward as often as two or three times in a single year. By 1942, according to Dr. Krauch, the Commissioner General, 1,480,000 tons of steel had been expended for new explosives plants. Between 1934 and 1938 the number of workers in the explosives industry rose from about 1,500 to 30,000; in 1944 it was 100,000. Figure 57 shows how the industry expanded between 1933 and the lost year of the war (see also Appendix Table D1). In four years, 1934 to 1938, powder production was increased to 5,000 tons per month, and explosives production to 10,000 tons per month. About half of the latter was pure high explosives, and the rest extenders or diluted explosives, chiefly ammonium nitrate. By the beginning of the war, the Germans had built up a stockpile of 187,000 tons of powder.

Raw Materials - A Critical Weakness

The German position in explosives, however, was vulnerable at some points. The weakest spot was raw materials. The Germans seriously underestimated their needs. In 1939 they estimated they would use 27,500 tons a month of concentrated nitric acid (Hoko) and 4,080 tons of tolulene; actually in 1944 their average monthly consumption was 70,000 and 10,000 tons, respectively. They built few raw materials plants but relied instead on private industry. They also failed to build up adequate stockpiles. During 1941-43, their average reserve stock of nitric acid, for example, was only a ten-day supply; they had less than a month's reserve of toluene, and no reserve at all of stabilizers. Their stock of glycol was practically used up by the need for anti-freeze in the winter of 1941-42.

The Germans also made a serious mistake in appraisal of their early lessons in combat. After their quick victories in Poland and France, they decided that blitzkrieg warfare required little ammunition, and they stopped expanding explosives manufacture. Stalingrad and other reverses in Russia made them resume expansion in 1943, but it was too late; they had fallen dangerously low in production of nitric acid and other raw materials.

In an effort to compensate for their shortages, they developed or adopted several technical innovations, of which the chief were:

(a) Development of DEGN (diethyleneglycoldinitrate as a substitute for nitroglycerin;

(b) Development of a process for the synthesis of toluene from benzene and methanol;

(c) Adoption of more economical processes for the manufacture of hexogen;

(d) Adoption of a foreign process for synthesis of glycerine.

The Nazis built two synthetic glycerine plants, one at Oppau and one at Heydebreck, and a synthetic toluene plant at Waldenburg, which produced about 35 percent of their total toluene supply.

Preparations against Bombing

Expecting that the powder and explosives industry would be a target for Allied bombing, the German High Command provided a very large excess capacity for manufacture. Tables D2, D3 and Figures 33, 34, 35, and 36 in the Appendix give the locations, production capacities, and managements of explosives plants. It is evident from the maps that the industry was well dispersed throughout the interior of Germany. The Germans took care not to place explosives plants in the danger zone (Freimachungszone) from which they intended to evacuate industries.

They followed no fixed pattern in organizing production. Some plants specialized in powders and/or explosives, some made fuzes and primers as well, and some even loaded shells. Munitions loading capacity kept pace with the expanding powder and explosives industry, and there was excess capacity throughout the war. In the Appendix, Figure 37 gives the data on the loading plants, Tables D4, D5, and D6 and Figures 38, 39, 40, 41, and 42 the data on the principal raw materials plants.

The industry was vulnerable to bombing because of its dependence on transportation. Nitrocellulose was usually made in one plant and shipped to another, in the form of moist paste. Contrary to American practice, only one plant, Christianstadt, made its own nitric acid. (All nitrating plants recovered spent acid.)

Another vulnerable, aspect was the concentration of certain important elements in a few bottleneck plants. Powder stabilizers, for example, were made only at Wolfen and Uerdingen.

Rise and Fall of Production

Figures 58 and 59 and Appendix Table D7 show Germany's production month by month, as measured against consumption, for powders and explosives, respectively, for the period 1940-44.*

Appendix Table D7 indicates that, until the middle of 1944, the Germans had ample ammunition. In the middle of 1943, after Stalingrad and later reverses in Russia, they gave explosives top priority, along with oil, and resumed the building of new plants (certain raw materials, notably diglycol and nitric acid, had top priority from 1942 on). In 1943, and until the middle of 1944, explosives and powder production was close to capacity, rising to peaks of 24,700 tons of powder and 51,000 tons of explosives in May-June, 1944.

Nevertheless, these strenuous efforts and the German reserves were not sufficient to meet the mid-1944 crisis resulting from
(1) The huge increase in munitions requirements after D Day and
(2) Stepped-up Allied bombing.

Direct bombing of the industry did not begin until very late in the war (early 1945). But the Allied bombing of four large oil plants (Leuna, Oppau, Linz, and Heydebreck) in 1944 had brought the explosives industry practically to a standstill. It not only destroyed much of the industry's raw material resources, but also diverted much of its labor and equipment to repairing oil plants. It wrecked explosives, too, because, as pointed out in an earlier section of this report, the Germans used their oil plants to produce critical raw materials for explosives as well.

In order to arrive at some idea of the movement of stocks, the Oil Division has assumed that no great stockpiles were available on 1 January 1940. On the basis of the monthly production and consumption of high explosives, the picture was as shown in Table 29.

TABLE 29

CUMULATIVE STOCK, AVERAGE MONTHLY CONSUMPTION FOR POWDER AND EXPLOSIVES


Cumulative Stock, TonsAverage Monthly ConsumptionNumber of Months for which Stocks Were Adequate
1 January 194198,1005,87017
1 January 1942163,13313,74612
1 January 1943197,42421,3709
1 January 1944227,82428,8007
1 January 194598,22252,0001.9
Similar calculations for powder will give the following results:
1 January 194149,0002,15022.7
1 January 1942107,9004,45028.2
1 January 1943165,1827,55021.7
1 January 1944253,3828,35030
1 January 1945209,38217,00012.3

Figure 60 shows how precipitously explosives production fell after the knockout of nitrogen. The Germans diverted some nitrogen to explosives from other industries, but it was not nearly enough. By February, 1945, German explosives supplies had been reduced to a trickle - 8,500 tons per month. This was only about 25 percent of the output for October, 1944. By that time the Germans were driven to such emergency measures as converting from 105-mm howitzers to 75-mm, because the smaller guns could fire twice as many projectiles with the same amount of explosives.

The disastrous German position in explosives was reported to Adolf Hitler by Munitions Minister Speer as early as 30 August 1944:

The last air attacks bave again badly hit the most important chemical plants - among them the three hydrogenation plants (Leuna, Brux, and Poelitz ) have out of operation for several weeks . . . Methanol production receded from the quota of 14,000 tons to 8,750 tons in August . . . in the field of the valuable explosives (hexogen and TNT) ... the production will fall 30 percent short.. . The production of nitrogen will amount to a maximum of 45,000 tons, compared to the planned production for September of 85,000 tons.

There were other widespread effects. The first desperate move the Germans made, in order to conserve nitrogen for explosives, was to cut heavily the nitrogen allocations for fertilizers and mining explosives. In prewar 1938-39, agriculture got 19.3 lb of nitrogen per acre (a total of 745,000 metric tons). In 1943-44, it got 10.25 lb per acre. For the season 1944-45 its all was only 4.45 lb per acre. Obviously this had a great effect on food production. The situation in mining was not better. The curtailment of explosives reduced coal production, which in turn reduced explosives production, creating a vicious circle.

Another damaging result was the deterioration of military explosives. The Germans had to give up almost entirely the manufacture of the powerful explosive hexogen, which because of its insensitivity was very desirable for armor-piercing shells. This explosive used a large amount of ammonia and methanol, and the Germans decided that TNT had first call on those materials.

The Germans also went in for filling shells with diluted explosives, which reduced their power. The chief extender used was ammonium nitrate. But there was also a large-scale use of inert extenders, mainly rock salt. Some of the German shells contained as much as 70 percent rock salt, with only 30 percent TNT. The extent to which extenders reduced the effectiveness of shells was estimated by Dr. Sarrazin, of the German main committee on powder and explosives, as follows:

Explosive MixtureFragmentation*, Meters
100 percent TNT40
60/40 TNT/ammonium nitrate38
30/70 TNT/ammonium nitrate34
60/40 TNT/rock salt28
50/50 TNT/rock salt26.3
40/60 TNT/rock salt25

* Fragmentation was defined as the distance in meters at which a target of 1 sq m, mounted on a block 2 m high, was pierced by only one bomb fragment from a standard explosive test bomb.

The German explosives shortage was aggravated in some respects by a rigid adherence to production schedules which overlooked changes in conditions. The Germans continued to allocate scarce nitric acid to propellants, for instance even after propellants had run far ahead of explosives and there was a good deal more powder than there were explosives.

As to the military results, these were perhaps best summarized by Field Marshal Keitel. About the situation in the last months of the war, he said:

Ammunition was short from time to time, especially for armored vehicle weapons. On the eastern front, many ammunition dumps were lost during the retreat. During the invasion, as well, we had lost large quantities of ammunition. When an ammunition plant was destroyed or heavily hit, there would be a shortage for a few weeks. We never had enough for our tanks and tank destroyer guns, as well as for all our defensive weapons.
Another reason was that we had a lot of ammunition tied down in other theaters of operation, as for instance in the Balkans, Hungary, Rumania, Italy, and so on. We had to store in all these places a minimum amount which would enable us to fight until more supplies could be brought up. In the North we had to keep an eight weeks' supply of ammunition.... Smoke was also very short.

Analysis of Bombing Effects

The powder and explosives industry was selected for never selected for intensive strategic bombing. It not even listed on any of the bombing plans. Toward the end of the war, munitions depots were given fourth priority, but neither the sources of powder and explosives nor the plants producing raw materials were ever made specific objectives with the purpose of knocking out the industry.

Right - Figure 61. Violent secondary explosions set off by incendiaries at Lignose Sprengstoff Werke, Schoenebeck, destroyed the TNT manufacturing building which once stood in the foreground.

In the last few weeks of the war, a few powder and explosives plants were subjected to bombing when other targets became scarce. But apparently no discrimination was used in selecting targets. For instance, the Dueneberg plant of Dynamit A. G. and the Kruemmel plant, 4 mi away, from which the Dueneberg plant got its raw cordite paste, were both bombed the same day. The destruction of Kruemmel would have closed Dueneberg, and so there was actually no necessity for bombing Dueneberg.

Air raids on the high-explosives industry before January, 1945, had no effect whatever on the ability of the Germans to meet their high-explosives requirements. There was enough unused capacity to absorb the mild shock of the earlier bombing. The decline in production during this period was caused not by lack of plant capacity but by lack of raw materials.

Most of the effective bombing of the explosives plants took place during the last six weeks of the war, when the Germans were already so nearly out of nitrogen that they were also out of the war. But the explosives industry could have been knocked out in earlier stages of the war and the loss of its productive capacity have had a profound effect on Germany's ability to continue the war. At the rate of expenditure of explosives by the German armed forces after D Day (70,000 tons per month), reserve stocks would have lasted only three to four months.

Left - Figure 62. Explosion resulting from fire started by incendiaries completely destroyed the TNT granulating buildings of Lignose Sprengstoff Werke, Schoenebeck, which once stood on this location. Extensive precautions taken by the Gemans were unavailing against a combination of high explosives and incendiaries properly aimed.

In order to cripple Germany's ability to wage war, it would have been necessary to knock out only 7 of a total of 35 powder and explosives plants: namely, Allendorf, Bromberg, Clausthal, Hessisch-Lichtenau, Kruemmel, Schlebusch, and Elsnig. These plants, with a combined capacity of 20,200 tons per month, accounted for 70 percent of the total German TNT capacity. Another good target would have been the manufacture of stabilizers, which was concentrated in two plants.

If properly selected weapons (incendiaries preponderating) and pattern bombing are used, the expenditure of effort required to put an explosives or powder plant out of commission is much less than other types of plants. A raid on the Schoenebeck plant of Lignose Sprengstoff Werke G.m.b.H. is a good illustration of this point. It required only 4.3 tons of incendiaries and 2 tons of high-explosive bombs, droppred by two Halifax bombers, to accomplish a 50 percent permanent reduction in the TNT capacity of this plant. The area of the plant was 125 acres; consequently the bomb density was 0.05 ton per acre. When one considers that it took hundreds or even thousands of tons on other types of plants to get similiar effects, these results are amazing. At Schoenebeck, the incendiaries started uncontrollable fires, which set off secondary explosions so great that there were only holes in the ground left where buildings had stood (Figures 61, 62, and 63).

Right - Figure 63. Great destruction was caused when the explosives plant of Lignose Sprengstoff Werke, Schoenebeck, was attacked 21 January 1944 by two RAF Halifax heavy bombers. Two 2,000-lb HE bombs and 1,748 4-lb incendiaries were dropped. Both HE's hit buildings and destroyed them, but by far the greater part of the damage was caused by incendiaries. The picture shows the destructive effects of fire alone on this type of plant.

In raids on explosives plants, the aim is to start fires, drop anti-personnel bombs to prevent the enemy from putting the fires out, and let the secondary explosions finish the job. In every one of the plants surveyed, most of the damage was caused by secondary explosion, either from fire or direct hits by high-explosive bombs. The recuperability of powder and explosives is of a very low order. Even under the most favorable conditions, it takes six to nine months to restore a plant to its original capacity. The German explosives plants were particularly vulnerable to low level air attacks, because they lacked anti-aircraft or fighter plane protection.

Effects on the Industry

Table 30 shows how bombing effected the productive capacity for the various raw and finished materials in the industry as a whole, and the industry's position on 15 February 1945.

Table 30

Status of German Explosives and Related Industries on 15 February 1945*

ProductTotal Capacity 100 percent Tons/Month Total Loss Tons/Monthpercent of CapacityTemporary Loss Tons/Monthpercent of CapacityOperable on 15 Feb. 1945 Tons/Monthpercent of Total Capacity
Trinitotolulene22,0001,2005.0%1,5002.0%19,30087.7%
Hexogen2,6001,70065.0%

90035.0%
Solventless cordite19,2003,10017.0%1,5008.0%14,60075.0%
Concentrated nitric acid62,5009,95015.9%1,6002.6%50,95081.5%
Oleum93,0007,2007.8%22,36524.5%63,17568.0%
Methanol30,57521,00068.8%5,00016.3%4,57515.5%
Tolulene12,5003002.4%8,70069.6%3,50028.0%
Hexamethylene-tetramine4,6502,85061.5%00.0%1,80038.7%
Pentaerythritol1,02500.0%30029.2%72570.8%
Ethylene oxide7,1001,25017.6%1,25017.6%4,60064.8%
Diglycol3,85070018.2%1,15030.0%2,00051.8%
Stabilizers1,12000.0%55049.0%57051.0%
Guanidine nitrate1,95000.0%00.0%1,950100.0%
Nitro guanidine1,00000.0%60060.0%40040.0%
Methyl nitrate1,0101,00099.0%00.0%101.0%
Methylamine nitrate salt1,0001,000100.0%00.0%00.0%
Dinitro anisol35000.0%00.0%350100.0%
Dinitro benzine3,45045013.2%70020.6%2,30066.4%
Nitrocellulose19,0004,15021.8%7704.2%14,08074.0%
Ammonium nitrate30,00011,00036.8%5,00016.7%14,00046.8%
Ammonia as (N)71,30010,20014.3%56,10078.8%5,0006.9%
* This table taken from a captured German document. The figures for methanol and ammonia are not in agreement with those established by Oil Division research.

These figures indicate that explosives manufacturing capacity was hardly touched by the Allied raids, whereas raw materials, rarely a primary target, suffered very heavily as the result of oil plant raids and the capture of plants. On 15 February, the Germans still had 87.7 percent of their TNT capacity, for example, but ammonia productive capacity was down to 6.9 percent.

Effects on Individual Plants

Dueneberg. This plant, attacked by 151 Eighth Air Force B-24's on 7 April 1945, with 26 tons of 1,000-lb high-explosive bombs, 381 tons of 500-lb bombs, and nine 100-lb incendiaries, a total of of 408 tons, was hard hit. A total of 219 tons dropped in the plant area. Several secondary explosions resulted, the most spectacular being the detonation of 200 tons of nitroguanidine in bulk storage. The explosion destroyed all buildings and installations within an 850-ft radius. German officials estimate that it would have taken three to four weeks to make enough repairs to restore production capacity to 20 percent, but the management did not repair the plant because it realized the end of the war was near. It was not possible to determine whether the incendiaries or high explosives, or both, caused the secondary explosions (Figures 64, 65, and 66).

Right - Figure 64. The Dueneberg plant of Dynamit A.G., which produced 13.6 percent of Germany's propellant powder, was hit by 800 HE bombs and 9 100-lb incendiaries on 7 April 1945. A crater 210 ft in diameter resulted from a secondary explosion when a bomb scored a direct hit on a magazine containing 200 tons of nitroguanidine. Three adjoining buildings were destroyed and all buildings and installations with an 850-ft radius were badly damaged. The explosion may have been caused by either HE's or the incendiaries. Production could have been restored to about 20 percent capacity in three to four weeks.


This 175-ft crater resulted from explosion of a magazine containing 80 tons of rocket powder following the 7 April 1945 raid on the Dueneberg plant of Dynamit A.G. when a lone fighter bomber shelled the plant area.The explosion resulting from a bomb hit on a 50-ton powder magazine left this crater 100 ft in diameter and 45 ft deep in the plant area of Dynamit A.G. in Dueneberg.

Kruemmel. This plant was hit as the same day as Dueneberg by 118 B-24's, which dropped 325 tons of high explosives, mostly 500 lb., and 0.5 ton of incendiaries. About half the tonnage was in the target area. No incendiaries dropped on the target, and their were no secondary explosions. Damage totalled 15 percent of the plant cost, but it completely stopped production. Facilities for TNT production could have been restored 25 to 50 percent in two weeks, but it would have taken a year to bring the nitrocellulose plant to full capacity (Figure 67).

Explosion of an RDX bomb inside the glycol nitration building of the Kruemmel plant of Dynamit A.G. broke the supporting columns and caused collapse of the roof and ceiling. Heavy equipment suffered only slight damage.Disruption of the piping system in the TNT building as result of the 7 October 1944 attack by the Eighth Air Force on the Clausthal-Zellerfeld plant. The 750 acre plant area was hit by 95 tons of HE bombs. Of the 214 buildings, 70 were hit and 5 destroyed. Main damage was to underground and surface piping, including 100 percent destruction of the product mains and 70 to 80 percent damage to the other lines. Six months were required to bring the TNT production in this plant back to 50 percent of its preattack capacity.

Clausthall. This plant was raided on 7 October 1944, which dropped 363 tons of bombs (338 1,000-lb bombs and the rest 500, 300, and 250 lb). About, one fourth of the bombs landed in the target area. The plant, engaged, in TNT production and shell loading, was not operating when bombed. Of its 214 buildings, 70 got direct hits and there were 53 direct hits on the piping system. There was only one secondary explosion - a magazine. When the bombs penetrated concrete roofs and exploded inside they destroyed column supports and collapsed the roof, damaging heavy equipment. But glancing hits and near misses left the heavy equipment undamaged. Hits between the buildings and blast walls caused heavy destruction. The most severe damage in this plant was to the piping system; the bombing knocked out the products mains entirely and destroyed steam, air, warm water, and sewage mains 70 to 80 percent. To restore 50 percent of capacity would have taken three months for shell loading and six months for TNT (Figures 68, 69, 70).

Left - Figure 69. Lightly constructed walls were blown out, but heavy nitrators suffered only slight damage from the blast effect of a 1,000-lb bomb in the TNT building of the Clausthall-Zellerfeld plant.

Right - Figure 70. Column supports collapsed and the roof fell in on the acid tanks when a 1,000-lb bomb hit the roof of the spent acid storage building of the Clausthall-Zellerfeld plant. Pipe lines and three acid pumps were destroyed by falling roof, and several tanks were severely damaged.

Schoenebeck. On 24 January 1944, two Halifax bombers dropped 2 tons of high explosives and 4.3 tons of incendiary bombs on this target. The destruction was amazing, owing to the secondary explosions caused by fires. The capacity of the TNT plant was reduced approximately 50 percent. No attempt was made to repair it. It took ten months to restore the electric fuse plant to full capacity.

A TNT wash house, two ganulating buildings, a crude TNT drying room (which contained about 6 tons of TNT) and a trinitration building were completely destroyed. Heavy pieces of equipment were found 900 ft away from the trinitration building, and only a deep crate was found on the building site. This is the only one of the explosives plants surveyed where incendiaries were used in great quantity (Figures 61, 62, 63).

Right - Figure 73. A 500-lb HE bomb dropped by the Eighth Air Force hit the powder magazine at Deutche Spregchemie, Kraiburg, on 11 April 1945, completely destroyed the magazine, and lifted its roof into the position shown. The building beyond, to which the magazine was attached, suffered blast damage. The crater caused by the explosion was 70to 80 feet in diameter and about 15 ft deep. Secondary explosions and fires usually augmented bomb damage done to explosives plants, especially when the plants were subjected to high-explosive are bombing, supplemented by incendiaries.

Kraiburg. This target was attacked 11 April 1945 by 133 B-17's which dropped 381 tons of 500-lb bombs. No bomb plot was available. Destruction was so extensive that production was stopped completely. The heaviest damage was caused by secondary explosions. In one case, a magazine holding nipolit and 18 to 20 tons of raw powder was hit and exploded. The crater was 20 to 25 ft deep and 75 to 80 ft in diameter. The blast was so great that tree 175 to 200 ft away were blown down (Figures 71, 72, 73).

Above - Figure 71. This hydrogen peroxide storage tank at Deutsche Sprengchemie, Kraiburg, had been buried in the ground to a depth of one quarter its diameter and then covered with earth. A 12-in. concrete housing had been built to enclose the covered tank, after which the concrete structure was mounded. The mound was hit by a 500-lb HE bomb in the attack of 11 April 1945. The resulting secondary explosion tore the 0.4-in.-thick aluminium tank apart and threw the pieces 100 ft to either side.

Troidsdorf. One of the largest plants in Europe, producing industrial primers, fuzes, and detonators, this plant was hit on 27 December 1944 by 11 B-17's and two days later by 176 RAF heavy bombers in spillovers from another target. The British airplanes dropped 12 two-tons bombs, among others, and the total tonnage was 626. Troisdorf caught 100 tons of this, a total of 364 bomb hits. The metalworking building, making casing for detonators, was completely destroyed, and no attempt was made to rebuild it.

Table 31

Loss of Explosives and Powder Production from Bombing of Surveyed Plants

PlantDate of RaidProduction, Tons per MonthProduction Loss, Tons per Month
Schoenebeck21 January 19441,000 (Exp)500
Clausthall7 October 19443,000 (Exp)3,000
Krümmel7 April 19453,700 (Exp)3,700
Düneberg7 April 19453,000 (Pow)3,000
Kraiburg11 April 19451,800 (Pow)1,800

Protective Measures. The German explosives plants had two types of defense against bombing, both ineffective. One was the construction of large excess capacity in plants well dispersed over the country. This failed because of the raw material bottleneck.

Right - Figure 74. Kruemmel plant of Dynamit A.G., one of the largest in Germany, with a production capacity of 3,000 tons of TNT and 3,800 tons of raw cordite paste per month. It also had a shell-loading plant and produced several other types of explosives. A total of 790 buildings of various types, ranging from ordinary wood construction to reinforced concrete structures carefully protected by blast walls, were dispersed in an area of 794 acres. The functional pattern of plant divisions is easily recongnizable. The natural camouflage and wide dispersion of structures are typical of nearly all German explosives and powder plants.

The other was protection of the plants themselves. The buildings were well separated from each other and arranged in irregular patterns (Figures 74 and 75). They had reinforced concrete roofs, covered with soil and growing vegetation for camouflaged. Buildings were surrounded by blast walls of 6-to 27-ft reinforced concrete core with a 12-ft earth abutment on each side. The walls often had corridors which served as shelters.

There were also reinforced concrete and sandbag walls around the central power plant and important equipment, for fragment protection. Other measures were good blackout control and decentralized fire-fighting equipment.

The main reliance was on the natural camouflage. The plants surveyed had no smoke screens, no flak (heavy flak was considered dangerous because of falling fragments), no dummy buildings, no fighter protection.

Conclusion

In view of the facts established by the survey and more specifically described in the target reports, it is reasonable to conclude concerning air attacks on explosives and propellants plants such as the Germans', which consisted of a large number of buildings of comparatively light construction, which were protected by blast walls, which were connected by an intricate piping system, and which dispersed over a large area, that:

(1) Pattern bombing should be used in preference to so-called precision bombing, and
(2) Incendiaries mixed with anti-personnel bombs should predominate, and this combination should be salted with a limited number of 500- and 1,000-lb boms to open up the buildings and disrupt the piping system.

Below - Figure 75. In this view of the Kruemmel plant, dispersion of the buildings in more plainly seen than in the aerial view. There are blast walls around buildings. Small circles show bomb hits. The plant was hit by 325 HE bombs on 7 April 1945. It would have required 5,000 to 6,000 working hours to restore TNT production to its full capacity. The nitrocellulose plant could have been restored to 15 percent of its capacity with four to five weeks; its complete restoration would have required about 12 months. Other sections of the plant (nitro-penta, TNT pressed bodies, hexogen, nitroglycerin, etc.) would have required four to six weeks for restoration. The shell loading plant was left intact.

Special Propellants for Rockets and Jet Propulsion

In the last year of the war, the Allies naturally had a special interest in propellants used for the V weapons and jet-propelled submarines. The plants making these propellants might well have been considered the Number 1 targets in the propellants and explosives industry. Unfortuntately, the damage done to German raw material supplies had littel effect on rocket production, which used certain special materials manufactured for that purpose alone.

The first of the German rocket weapons was the Nebelwerfer, a multibarreled projector which fired rockets filled with smoke acid, chemical agents, or explosives. It was developed before the war. Its rocket propellant was a molding of Pol powder (solventless cordite), produced by a special process and apparatus developed for continuous plasticizing and extruding of the powder in large rods. This powder was included in the powder production discussed earlier in this report.

Early in the war, the Germans began intensive research to develop better rocket and turbojet propellants. A large research station staffed with top-notch scientists and technicians was set up for this purpose at Peenemunde. Another center at Kiel concentrated on development of jet-propeIled submarines.

The Germans tried a number of available oxidizing materials and fuels, including concentrated nitric acid, Visole (vinyl ethers), gasoline, diesel fuel, etc. They finally settled on concentrated hydrogen peroxide (85 percent) as the principal oxygen carrier, used with hydrazine hydrate, pyrocatechol, or crude oil as a fuel. Liquid oxygen in combination with methyl or ethyl alcohol also was used. Figure 79. Complete destruction of these hydrogen peroxide distillation columns shows the effectiveness of light (500-lb) high explosive bombs on lightly constructed chemical processing equipment. This damage occured at the Elektrochemische Werke Muenchen, Hollriegelskreuth, on 19 July 1944 and completely stopped production.

The Germans, placing high hopes on rockets jet-propelled weapons, gave these materials a very high priority.

Concentrated hydrogen peroxide (85 percent) was produced in two stages: first a 30 to 35 percent concentration was obtained by the electrolysis of sulfuric acid or ammonium bisulfate: then this product was distilled to 85 percent strength with special equipment. The two processes were often carried out in separate plants. Hydrazine hydrate was made by the controlled reaction of sodium hypochlorite with ammonia, followed by distillation for purification and concentration. In the combined propellant the Germans used a permanganate catalyst for decomposition of the peroxide.

Large-scale production of 85 percent hydrogen, peroxide apparently began in 1941. By the middle of 1943, the monthly requirements for rockets and jet propulsion included, among others, 7,000 metric tons of concentrated hydrogen peroxide, 22,500 of nitric acid, 13,000 of liquid oxygen, 4,000 of ethanol, 800 of hydrazine hydrate, 9,000 of explosives. Of these, hydrogen peroxide and hydrazine hydrate were the only materials unique to the rocket program.

Dilute hydrogen peroxide (30 to 35 percent) was produced in ten plants, of which the most important were those at Hollriegelskreuth, near Munich, and at Bad Lauterberg, in the Harz Mountains. Concentrated hydrogen peroxide was produced in two plants at the same locations; at the end of the war other plants were under construction. Hydrazine hydrate production was concentrated in three plants, at Ludwigshafen, Leverkusen, and Gersthofen. One plant, in Hollriegelskreuth, produced all of the vital permanganate catalysts.

Methods and processes for producing these materials were neither so highly organized nor so stable as those in the rest of the propellants industry. The Germans experimented constantly with new materials and processes. An interesting sidelight was their persistent efforts to adapt nitric acid as an oxygen carrier. It turned out to be unsatisfactory for use in submarines, because its exhaust gases left telltale bubbles in the wake of the craft. During the last months of 1944, the nitric acid shortage threatened to put a crimp in the Germans' V and jet-propelled weapons. But they were expanding hydrogen peroxide production rapidly. Figures 76 and 77 show the rise in production in 1944 and the planned increases in 1945.

The Unbombed Plants

Germany's plans and the testimony of her engineers emphasize how heavily the Nazis gambled on rockets and jet propulsion. They expected their jet-propelled planes to stop the Allied bombing operations, and had great plans for the expansion of V bombing, with which they hoped to destroy the Allied bases, pin down the air forces, and force a land war on the Allies - which they were sure they could win.

In view of these facts and the difficulty of coping with such weapons as V-2 at the operational end, it is surprising that Allied bombing so thoroughly neglected the vital propellants plants. The hydrogen peroxide and liquid oxygen plants were extremely vulnerable: they were of light construction, and much of their equipment was fragile - glass or chemical stoneware. They also offered well-concentrated targets. Their immunity may have been caused partly by inadequate intelligence work. Intelligence reported, for example, that hydrogen peroxide was manufactured at the Linde Eismaschinen plant in Hollriegelskreuth; actually the product manufactured here was liquid oxygen. Some bombed locations which intelligence identified as factories turned out to be only storage depots.

Only two of the ten German plants making 30 to 35 percent hydrogen peroxide were ever hit, and even those bombings caused only a few days' loss of production. The big plant for 85 percent hydrogen peroxide manufacture at Bad Lauterberg was never bombed, and there is no record that the important Gersthofen hydrazine hydrate plant was a primary bombing target.

Surveys were made of the bombing effects on three rocket propellants plants - Elektrochemische and Linde Eismaschinen at Hollriegelskreuth and Henkel and Company at Holthausen. The two Hollriegelskreuth plants were raided together on 19 July 1944. Of the 266.5 tons of high-explosive bombs dropped, 32.25 hit Elektrochemische and 30.75 Linde Eismmaschinen.

Right - Figure 79. Complete destruction of these hydrogen peroxide distillation columns shows the effectiveness of light (500-lb) high explosive bombs on lightly-constructed chemical processing equipment. This damage occured at the Elektrochemische Werke Muenchen, Hollriegelskreuth, on 19 July 1944 and completely stopped production.

At Elektrochemische, facilities for 30 percent hydrogen peroxide were completely destroyed, but the real bottleneck, 85 per hydrogen peroxide, was virtually undamaged; it lost only a few days' production because of powerplant damage (Figures 78 and 79).

Figure 78. These views show a high degree of destruction by HE bombs on buildings of Elektrochemische Werke Muenchen, Hollriegelskreuth. Only the five-story hydrogen peroixide building remained intact. The plant (which included the adjacent plant of Gesellschaft fuer Linde Eismachinen A.G.) was hit on 19 July 1944 with 242 HE bombs, 70 of which hit buildings.

At Linde Eismaschinen, liquid oxygen production was knocked out, but the plant's some 120,000 cu m per month was probably 1 percent of the total German liquid oxygen production. More useful damage occured in this plant to facilities for manufacture of gas liquefaction equipment.

At Henkel and Company, hit in four separate attacks, but a primary target in only one, on 21 May 1944, the 2.33 tons of bombs dropped caused only slight damage and did not affect production.

These three plants had many well-concentrated buildings. Analysis of the bombing results indicates that such plants should be hit with 500-, 1,000-, and 2,000-lb high-explosive bombs and some incendiaries. The bombs should include some with instantaneous fuzing and some with 0.025-fuze settings. A bomb density of 2 tons per acre is recommended.

But the fact remains that the 85 percent hydrogen peroxide plants, the core of the rocket propellants industry, were almost unscathed by bombing. The light bombing of this industry had no effect on the German rocket program during 1944 and early 1945.

In modern war a country's ability to produce munitions decides victory or defeat. The destruction or crippling of the munitions industry is the key to victory.
A systematic attack on the key points of the munitions industry could have ended the war with Germany one year earlier. Basic chemical raw materials, special steels and the transport systems serving these plants should have been special objectives.

Major General Henrici
Chief of Ordnance, German Army


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