Chapter 8: Large Area Smoke Screens in the MTO
It was the fate of the Chemical Warfare Service to enter World War II with rather ill-defined responsibilities, a circumstance accented by the absence of its most clearly defined mission—gas warfare. As a consequence, responsibilities were delineated and missions took shape as the necessity for meeting new conditions actually arose in the theaters of operations. A case in point was large area screening. The tremendous development in air power between the world wars produced a situation which made the concealment of ground targets a prime necessity. Clues pointing to this development were apparent in the 1930s but for various reasons little had been done to prepare for large area screening. The first adequate American smoke generator did not appear until 1942. Once the generators were in the theaters, a chain of circumstances created smoke missions which were unknown even in the tentative doctrine of the prewar period.
Background of Large Area Screening
Experiment and Trial
Although the employment of small quantities of smoke in combat was an ancient military technique, its use to conceal extended areas was a twentieth century innovation. The term large area screen is quite imprecise. The size of a large area screen depends upon the nature and size of the target to be obscured. The screen had to be large enough to baffle enemy bombardiers; if it were too small it would merely pinpoint vital areas. The technical aspects of large-scale smoke screening had been a CWS concern from the time that service received the smoke mission in 1920. The most immediate interest was in the development of agents and munitions to support tactical operations. Because initial CWS experiments in area screening along the Panama
Canal were unsuccessful, the search for agents and means of disseminating area screens continued sporadically until 1936 when the War Department decided that with the means available large area screening was not practicable.1
The high importance placed on hemisphere defense by the RAINBOW plans of 19392 revived War Department interest in providing passive defense for the vulnerable areas of the Panama Canal. On 1 July 1940 the War Department directed Maj. Gen. Walter C. Baker, Chief, Chemical Warfare Service, to submit an estimate of the costs of development, installation, and maintenance of smoke screening apparatus required for concealing the three locks. By the end of the month the War Department sent this estimate to the commanding general, Panama Canal Department, for comments. The Air Corps commander in the Canal Zone favored the project in principle but had some reservations. The commanding general of the Panama antiaircraft defenses opposed any extensive use of smoke which might nullify the effectiveness of antiaircraft fire. The department chemical officer advised his commander that in view of the lack of information about the effectiveness of large area screens it would be unwise to plan a costly screening installation for the three locks. The matter was held in abeyance.3 Nevertheless, two points had emerged from the Panama studies. First, technical means for generating artificial clouds were inadequate. Second, there was serious opposition by commanders to the employment of smoke during air raids. Until a better means of smoke production was devised, a mutually satisfactory decision about smoke employment was impossible.
At that time, the war in Europe provided actual combat tests of the use of smoke. Before mid-1940 British interest in large area screening had been rather theoretical—an interesting proposition but hardly practicable.4 When the German invasion of the Low Countries and
France in the spring of 1940 provided the Luftwaffe with airfields within easy reach of the United Kingdom, the British gave serious attention to the possibility of using smoke to conceal vital installations. At first, the British Ministry of Home Security, responsible for screening vulnerable targets, provided oil-burning orchard smudge pots for targets in Birmingham and Coventry. It waived smoke abatement orders so as to increase the industrial haze, no longer the public nuisance it had been in time of peace. The Admiralty Fuel Experimental Station at Haslar, England, later developed the first large-capacity oil-burner generator, cumbersome and inefficient but the best smoke producer available at the time.
The typical British large area smoke installation in 1941 consisted of several thousand stationary smudge-type oil pots and a few Haslar generators which gave body to the screen from upwind positions. Although requirements for oil, all of which had to be imported, and manpower were heavy, area screening proved well worthwhile. In addition to military advantage, smoke became an important factor in maintaining the morale of factory workers, especially in munitions plants. Employees sometimes demanded smoke, despite its inconvenience, as the price of continuing to work at night.5
Beginnings of Large Area Screening in the United States
The gradual transition of area screening from theory to practice was observed with interest in the United States. The Chemical Warfare Service carefully surveyed the development of European equipment and screening techniques and, with the Army Air Corps and other Army elements, investigated the problems which would accompany the development of large area screening.
In mid-1940 the only smoke-producing munitions available to the U.S. Army were smoke shells, pots, grenades, and airplane smoke tanks. These munitions were satisfactory for establishing transitory curtains and could be used to a limited extent for blanketing enemy positions, but they were unsuitable for maintaining smoke screens over wide areas of friendly terrain because of the limited amount of smoke they produced and because artillery and mortar shells could not be impacted
near friendly troops. Moreover, smoke from the HC-filled pots was harassing at best and in concentrated amounts could be quite toxic. Following the British lead, the CWS adapted the commercial smudge pot which was standardized as the M1 stationary oil generator. CWS scientists and later those of the National Defense Research Committee (NDRC) became interested in more efficient smoke production techniques. In 1942 there appeared an entirely new type of smoke generator, one which emitted a “smoke” composed of small particles of oil created when a superheated oil-vapor mixture condensed upon ejection into the air. Production began on this generator in September 1942, and it was standardized as the M1 mechanical smoke generator (often called the Esso, after the company which produced it) in the following December.6
In December 1941 the Chemical Warfare Board undertook a study of large area smoke concealment with particular application to Edge-wood Arsenal. Within a few days after the Pearl Harbor attack General Porter instructed the board to expand its objectives to include the general principles and techniques of screening, a project which was given highest priority.7 The investigations of the Chemical Warfare Board soon had proceeded far enough to establish several tentative principles of rear area screening. Observation from the air revealed that smoke at night changed the appearance of both natural and artificial terrain features. Smoke was of less value during daylight and might even accentuate vital targets. Blackouts would still have to be maintained at night because bright lights were visible through the smoke; in other words, rear area screening was supplementary to the blackout, not a substitute for it. And, finally, screening, while appreciably reducing visibility, would not eliminate observation from the air.8
After the completion of the Edgewood tests, the CWS felt better prepared to provide technical supervision of smoke installations in the zone of interior, which the Operations Division, War Department General Staff, was finding difficult to establish because of shortages of
men and matériel. The commanding generals of the several defense commands forwarded screening requests, arranged in order of importance, to the War Department, which compiled all requests, giving each a priority rating. The CWS aided OPD in this task by performing feasibility surveys for each proposed installation.9
Meanwhile, the CWS recommended the activation of thirty-four chemical smoke generator companies. On 8 April the first three units (the 75th, 76th, and 77th Companies) were formed and, before their training was completed, received the mission of concealing aircraft plants in California. By the end of May the War Department had authorized the activation of 11 companies to be stationed as follows: 6 with the Western Defense Command; 3 in Panama; one at the Sault Ste. Marie Locks; and one, an experimental unit, at Edgewood Arsenal.10 By 20 July a total of 14 companies had been activated, 9 located on the west coast of the United States.
Each of these early smoke units, organized under a table of organization calling for 4 officers and 196 enlisted men and 3,600 M1 stationary smoke generators (the smudge pot type)11 was capable of blanketing an area of about four square miles. Generators were employed in two or more concentric smoke lines which completely surrounded the vital area, allowing for wind from any direction. By the proper placement of additional generators and by use of an electrical ignition system, a substantial amount of smoke could be formed in about ten minutes.
When the United States entered the war the long-standing Panama Canal screening project was immediately revived. At the time, the smoke pot was the only screening munition available and it required too many men to make a Panama smoke installation feasible.12 The stationary generator proved more satisfactory, and, as a consequence, Lt. Gen. Frank M. Andrews, Caribbean Defense Command, recommended that plans for screening in the Department be implemented as soon as possible.13 By 1 January 1943 two smoke generator companies had
arrived in Panama equipped with the M1 mechanical generator. Used in conjunction with the stationary generator, this new equipment greatly eased the situation on the smoke lines.
In July 1942, with a practical means of screening assured, General Porter made several recommendations on plans for rear area screening which were approved by the General Staff. The War Department ordered that additional smoke generator companies be activated to bring the total to 42. These new units were to train at the CWS Replacement Training Center at Camp Sibert, where large area screening exercises could be freely conducted.14 By August 1942 troop basis planning provided for the employment of 12 companies in theaters of operations, 3 in Panama, and 14 by the defense commands in the zone of interior. Activation of chemical smoke generator companies continued at the rate of about 3 a month until February 1943, when a total of 40 had been organized.
Defensive screening operations during 1942 consisted of the establishment of zone of interior smoke installations and the development of screening readiness in Panama. Operations at the Sault Ste. Marie locks15 and at Camp Edwards, Mass., were primarily for experimental purposes, both tactical and technical. The requirement for smoke installations in the Western Defense Command began to decline after the defeat of the Japanese fleet in the Battle of Midway in June 1942 and ended with the increase in American air power during the early months of 1943. Smoke was never made in anger in the United States. But the anxious period after 7 December 1941 provided the impetus for rapid progress in the development of matériel and the organization of units. This was a necessary prelude to overseas screening operations.
Initial Operations: The Northwest African Ports
Early on the morning of 8 November 1942 British and American forces attacked Northwest Africa. The assault operations consisted of three distinct parts. The Western Task Force, entirely American and combat loaded in the United States, struck the coast of French Morocco in the vicinity of Casablanca. The Center and Eastern Task
Forces, mounted in Great Britain, had as their respective targets the Mediterranean ports of Oran and Algiers.16 The initial French resistance soon ceased, and the British-American forces turned east toward Tunisia.
By then the United States Army had attained a capability in large area screening which a year earlier would have seemed impossible. A new generator, the M1, had been devised, units were being activated to operate it, and the doctrine for its employment—the concealment of vital rear area installations—had become an accepted feature in the defense against air attack. The Northwest African campaign was to provide the crucial test of combat for this generator, these units, and this mission.
Although the Luftwaffe failed to react to the landings in Northwest Africa, enemy planes in the succeeding months raided Algiers and other ports to the east in an effort to disrupt Allied supply lines. Both the United States and Great Britain supplied troops and munitions for the large area screening mission. Shortly before, the British No. 24 smoke pot had been dubbed “the savior of Malta” for its part in shielding the island’s harbor from concentrated enemy air attacks.17 The Americans provided the M1 smoke pot and the M1 mechanical smoke generator, smaller and more efficient and maneuverable than the large British Haslar.18 These two generators, the primary equipment of the units performing the smoke mission, were to form the nucleus of the smoke installations at the Northwest African ports.
Because smoke was not required, no American smoke units participated in the initial landings, a fortunate circumstance in view of the limited number of available units. Elements of the 78th Smoke Generator Company did arrive at Casablanca on 13 November, five days after the shooting began.19 The company set up a smoke installation on 23 November which served principally for demonstration purposes.20
The first smoke company to see action in Northwest Africa was the 69th Smoke Generator Company. It landed at Oran on 25 December, and on the following day it relieved a detachment of engineer troops which, using British No. 24 smoke pots, had maintained a smoke line in the harbor since 9 November.21 By February 1943 both the 78th and the 69th Companies were at Algiers where they successfully operated their M1 mechanical generators in conjunction with a British company equipped with Haslars.22
All told, ten major North African ports had the benefit of smoke installations manned by troops from the United States, Great Britain, and France.23 These operations were not simultaneous but represented a steady movement eastward as the Allied troops, in conjunction with those under Generals Sir Harold R. L. G. Alexander and Montgomery, converged on the Axis concentrations in Tunisia. Bizerte, although captured just before complete victory in Northwest Africa, served as one of the chief marshaling ports for the invasion of Sicily and later Italy, thus becoming one of the Mediterranean’s most heavily screened ports. A British smoke unit was waiting on the outskirts of Bizerte on 7 May as the II U.S. Corps was capturing the city, and within twelve hours the port was screened. By the end of June all four of the American smoke generator companies in the theater were providing the smoke defenses for Bizerte. In addition to the 69th and 78th these were the 168th and 172nd, just arrived from the United States and still without generators.24
Smoke installations usually consisted of two rings, the size of which depended upon the area to be screened. An inner ring of smoke pots provided for the quick concealment of vital targets while an outer ring of mechanical generators built the main element of the smoke blanket. Pots were also used to fill in gaps in a blanket caused by shifting winds or by other unforeseen conditions. Smoke was made at night only; during the day fighter aircraft provided protection for the dock areas of the harbors.
Early on the morning of 6 July 1943, with Bizerte’s port, channel, outer harbor, and bay crowded with ships for the impending invasion of Sicily, the Luftwaffe attacked with a force of more than sixty aircraft. The smoke units had nine minutes warning. At 0409 the German bombers began their run on the smoke-obscured targets. Despite intense antiaircraft fire the enemy kept up an almost uninterrupted attack for thirty-six minutes. At 0445 the bombers withdrew, and the order to “cease smoke” came shortly after. During the 65-minute smoking period the units expended 4,135 gallons of fog oil and 535 British smoke pots. Although the enemy bombed several dumps and inflicted about a score of casualties outside the screen, no bombs fell within the vital area. The ships and docks were untouched and the channel remained open.25
In August two of the four American smoke units were alerted for the Sicilian operation. In September the remaining American companies sailed for Italy, and British troops manned the Bizerte screen until their relief by French units in January 1944.
By concealing the harbors and port facilities from Algiers to Sfax from enemy air bombardment, American and British smoke companies played a limited yet important part in the Northwest African campaign. The extent of the smoke operations depended upon the clearness of the night, the military traffic at a port facility, and the degree of enemy air activity. The Luftwaffe succeeded in sinking a few ships in these harbors and caused some damage to port installations, but its attacks on the ports in Northwest Africa were largely without effect.26
This first combat experience entirely justified the hopes of the designers of the mechanical generator. It produced substantial clouds of persistent white “smoke” with comparative speed. Although the weight of the generator required vehicular transportation and its fuel requirements were substantial, these were but modest logistical considerations compared with the results obtained.
Perfecting the Technique: The Italian Ports
The port of Naples was the initial Allied objective after Anglo-American forces had secured a foothold in southern Italy. The logistical
Map 3: Smoke at Naples, December 1943
considerations that demanded taking the port city naturally required the uninterrupted flow of supplies into its spacious harbor. The smoke installation that aided in this task was the most comprehensive of its kind in the war. And it had the benefit of the experience gained in screening the ports of Northwest Africa.
The vital shipping area at Naples included the port and harbor of the city itself, the port area at suburban Bagnoli, and the fine harbor at Pozzuoli in the Bay of Baiae. (Map 3) The smoke installation began operations in October 1943, reached a climax late in the year, and tapered off by the following summer as Allied successes farther to the north helped reduce the possibility of heavy enemy air attacks.
At its height the smoke lines were manned by the 163rd, 164th, 168th, 172nd, and 179th Smoke Generator Companies, the 24th Decontamination Company, and the British 807th (SM) Company—in all, about 1,000 officers and enlisted men.
At first, no common headquarters existed to direct the activities of these units, a fact which soon led to the establishment of a provisional smoke generator battalion headquarters.27 Although an improvement, this “provisional” headquarters was not the answer. The lack of status and the inadequate capability of this provisional unit, led by the senior smoke generator company commander, finally impelled the theater in March 1944 to request the assignment of a headquarters and headquarters detachment, chemical smoke generator battalion. This unit was urgently needed, the theater said, to provide centralized control over the several smoke companies in such matters as technical operations and administrative and logistical support. As a result, Headquarters and Headquarters Detachment, 22nd Chemical Smoke Generator Battalion, was activated on 5 May 1944.28
The smoke installation in the Naples complex included three sectors, each with inner and outer rings. The inner ring at Naples proper consisted of 370 British smoke pot positions and 14 Besler generators, a Navy generator, small, efficient, and much like the Army’s M2 which would appear later. The outer ring, about six miles long, included 86 mechanical generators. The Bagnoli sector had 100 smoke pot and 38 mechanical generator positions, the Pozzouli, 48 mechanical generators. The smoke from these installations blended into one massive screen extending at times for a distance of twenty miles. As in the case of the North African ports, smoke was used during the night and during the periods of twilight. The prevalent winds at these times were offshore, an ideal condition for the land-based generators, although ten craft loaded with floating M4 smoke pots were ready to cover any gaps caused by occasional breezes from the sea. Air turbulence from two nearby land masses created constant difficulty in the development of an adequate screen. One of these was the volcano Vesuvius whose mass and glow, according to captured German pilots, provided the
additional disservice of furnishing guides to attacking enemy bombers.29 Smoke orders came from the British 45th AA Brigade charged with the port defense.30
Enemy air raids were frequent and heavy at Naples, but its defenses—fighters, flak, and smoke—combined to blunt the effectiveness of the attacks. On the night of 26 November, for example, the screen confused and delayed the enemy flare laying aircraft to such an extent that the bomber formation released its load without benefit of flares. As a result, none of the bombs did damage, most of them falling into the bay.31
Although there was a letup in the number of air raids on Naples during the last half of March and April 1944, the tempo increased in May with the Allied drive on Rome, and the port was screened fourteen times. During one of the spring raids about 113 merchant ships and 60 naval craft were shielded by smoke in the ports and anchorages at Naples, all of which escaped damage.32 According to the AFHQ intelligence bulletins this was not exceptional; the screening activities at Naples were generally effective.33
As the Germans fell back before the Allied offensive their air attacks against Naples practically ceased. The smoke installation was gradually reduced to a single ring of pots around the harbor, manned by Italian personnel. Some of the American smoke units began to prepare for operation against southern France; others moved north to new ports, now that Naples was no longer able to supply efficiently the troops above Rome. During the advance northward the Fifth Army captured Civitavecchia, Piombino, and Leghorn, ports which upon repair were pressed into service to relieve the supply situation. Civitavecchia required but a small screen and that for a short time. The 179th Smoke Generator Company saw brief service there before moving to Piombino, where in June it joined with the 172nd Company in manning the smoke installation.34
Smoke screen shields unloading operations during air raid alert, Salerno
Activity at both of these ports subsided when the facilities at Leghorn, captured on 19 July, were repaired and gradually put into operation. Within a week the 179th Smoke Generator Company, to be joined shortly by three British companies, erected a screen at Leghorn. Initially, Leghorn represented a unique example of rear area screening in that it remained for some time within range of enemy artillery on the north bank of the Arno River. On 28 July the 172nd Company moved up from Piombino and deployed in a 7-mile arc at a distance approximately five miles north and northeast of the city. The haze from the generators, just as in the Anzio operation,35 denied to the enemy observation of port and road traffic. The company maintained the line, sometimes despite the objections of the Royal Navy in the port, for thirty-eight days, by which time the enemy had
withdrawn from his Arno River positions. The smoke installation at the port itself was continued until April 1945.36
Leghorn marked the end of American participation in port screening in the Mediterranean Theater of Operations. Rear area missions gradually petered out with the diminished effectiveness of the Luftwaffe. The 172nd and 179th Smoke Generator Companies, by now the only U.S. smoke units in Italy, turned to a type of employment that had evolved earlier in the theater—the use of smoke in forward areas. But before the development of that mission smoke units had been used in assault landings.
The Changing Mission: Smoke in Amphibious and Beachhead Operations
Salerno
The fighting in Italy proper saw an immediate extension of what had been the normal mission of smoke units. Thus far, in doctrine and experience, large area screens had concealed rear area installations exclusively. At Salerno smoke troops landed on D-day in support of the combat elements.37
The Fifth Army landings in the Gulf of Salerno, just around the Sorrento Peninsula from Naples, represented the first foothold of American troops on the mainland of Europe. Two corps participated in the attack—the British to on the left and the U.S. VI on the right. The 36th Infantry Division, forming the assault element of the American corps, drew as its objective the beaches near the town of Paestum.38
Each of the assault battalions, storming ashore early on 9 September 1943, carried about 200 M4 smoke pots.39 Dropped in the water by
infantrymen, the floating munitions helped conceal succeeding landing craft; placed on the beaches they screened exposed flanks. Navy personnel also employed smoke. Some support craft dropped pots; others were equipped with the Navy Besler smoke generator. This artificial smoke, combined with the morning mist and the haze of battle, created limited visibility. As a consequence, the enemy, with limited observation, resorted to a curtain of unobserved fire placed just off the beaches. This was in decided contrast to the initial situation wherein individual landing craft were reported to have been sniped at by enemy 8-inch guns.40
One CWS unit landed on D plus 2 as part of the beach force of VI Corps. The 24th Decontamination Company, under the ‘direction of the naval task force, used M1 and M4 smoke pots to screen the beaches and anchorages. Later, the Navy gave the unit eight Besler generators, a number gradually increased to thirty-six. Standard practice during the first week, when the issue was often in doubt, was to create smoke during the hours of evening and morning twilight and during moonlight, favorite times for German bombers to attack. During air raid alerts the smoke of the 24th Company usually was abetted by generators on naval craft. So effective was the smoke screen that beach and harbor were often concealed within three minutes of the alert. During the nights smoke came to assume the primary position among antiaircraft defenses.
Average daily expenditures during the first week on the Salerno beaches were 250 M1 and 100 M4 smoke pots and 5,000 gallons of fog oil. One of the principal difficulties encountered was the burning glow of the smoke pots which often served as aiming points for enemy bombers.41
Despite this handicap the smoke mission received new respect in the strongly contested battle for the Salerno beachhead. Troops and landing craft welcomed anything that would make them less vulnerable, and the pots and generators manned by infantrymen, sailors, and CWS
troops provided effective concealment from enemy fire.42 It was the opinion of naval officers with the shore control party at Salerno that the smoke screen saved many lives and landing craft.43
Anzio
The bold end run of Fifth Army’s VI Corps at Anzio has provoked much debate among postwar strategists, both armchair and professional. At the time, its planners felt that this maneuver would be the best way to break the stalemate encountered in front of the formidable German defenses which formed the Gustav Line. Unfortunately, Operation SHINGLE fell far short of expectations. The enemy responded quickly to the “abscess” in its flank and contained the beachhead in beleaguered impotency from its establishment on 22 January 1944 until the Allied breakout in the following May.44
As at Salerno, provision was made for a large area screen for the Anzio beachhead. Again as at Salerno, the 24th Decontamination Company was assigned this mission. The company, equipped with M1 and M4 pots and with eight Navy Besler generators, landed on D-day. On its first night ashore the unit smoked the beaches and anchorage, and within two days it had set up a smoke line almost two miles long. As the beachhead forces were augmented, other smoke troops, including a British unit and the U.S. 179th Smoke Generator Company, moved to Anzio to increase the size of the screen.45
Initially, smoke at Anzio was intended to be part of the antiaircraft screen. Experience had shown that a favorite enemy tactic was low level bomber attacks at dawn and at dusk. Consequently, it soon became standard practice to screen the port each day during the periods of dawn and dusk. The smoke troops also operated during red alerts at night, for smoke again proved to be the best antiaircraft defense during the hours of darkness. Throughout the first three weeks the Luftwaffe made at least one raid each night. Flares dropped by
lead planes seemed to be extinguished as they dropped into the screen. During daylight raids antiaircraft artillery and fighter planes constituted the sole defense.46
The decrease in the number of enemy air raids after mid-February, caused by effective antiaircraft defenses, brought little relief to the port and beachhead at Anzio, for the reduction of air attacks was accompanied by an increase in long-range artillery fire. Along the periphery of the beachhead and in the bordering mountains were innumerable enemy observation posts. Farm houses suspected of harboring German observers were demolished with 8-inch howitzers, and towers and nearby ridges were blanketed by chemical mortar and artillery smoke shell. But the mountains in the background continued to afford the enemy unrestricted view of beach installations and ships in the harbor. Although the entire Allied beachhead lay within range of enemy guns, the air defense, artillery, and naval commanders at first objected to smoking the beach and harbor during daytime because of possible interference with observation for friendly gunfire and with the unloading of the ships in the anchorage. This valid complaint was something to be reckoned with. Yet the losses incurred from enemy bombers and artillery were also worth taking into account. From 22 January through to February, for example, a daily average of almost twenty-eight tons of Allied ammunition was blown up by these means.47
To resolve this problem chemical officers, with the approval of Maj. Gen. Lucian K. Truscott, Jr., the corps commander, came up with a new technique for the mechanical smoke generator—the production of a light haze in the area between the harbor and the front lines, thin enough to permit normal operations within it, thick enough to prevent German observation from the encircling hills.48
To apply this technique the 179th Smoke Generator Company on 18 March moved from the harbor area toward the forward positions. The smoke line, now forming a 1 5-mile arc around the port, included nineteen generator positions on land and two generators mounted on Navy patrol craft in the harbor. (Map 4) The latter prevented enemy observation from the flanks of the concave contour of the coast line.
Map 4: Smoke at Anzio, 18 March 1944
After a period of trial, error, and compromise the smoke line was established just beyond the antiaircraft positions of the port and just short of the field artillery observation posts. The line was divided into four sections with generators spaced at 1,000-yard intervals. Smoke positions were connected by telephones, and each section had radio communication with the command post. The amount of smoke needed was determined by an observation tower in Nettuno, abetted at times by liaison planes borrowed from the artillery. Each hour an Air Forces
meteorology section provided weather data. Operations began one-half hour before dawn and ended one-half hour after sunset.49
The result was a light haze which, regardless of wind direction, denied observation to the enemy without restricting movement within the beachhead. Under concealment of this haze trucks were driven off LSTs (landing ships, tank) onto the beach, unloaded, and returned to the ships unmolested. This was a particularly important operation as the Allied troops at Anzio received an average of 3,500 tons of supplies a day for the 6 months after the January landings.50
Radio interception disclosed that German artillery was on the alert during daylight hours to take advantage of sudden wind changes which afforded brief views through the screen. Objections to the daylight screen which commanders had raised during the planning stage disappeared after the smoke operation began. Allied artillery units even requested and obtained additional daylight screening to hide the flash of guns, thus inaugurating a new mission for smoke generators.51 Another unusual mission of the 179th was in the interest of health. Generators, run at a reduced temperature for fifteen minutes during the morning and evening, spread a thin film of oil over the area. This oil film settled on the water and killed the larvae of the malarial mosquito, long a menace in the area.52
Soldiers going ashore at Anzio sometimes did not realize that smoke was being used. Lt. Raymond C. Stillger, who landed with the 34th Infantry Division three days after the daylight screening began, thought that the haze was a result of either a natural morning mist or smoke and dust from the battlefield. He noted that the mountain ranges were not visible from the harbor and that the artillery fire which dropped offshore was ineffective. When his unit moved forward, Stillger saw that the haze rarely drifted to within a mile of his position, usually remaining well to the rear. This was good; the infantry did not want the smoke to its front lest the Germans counterattack under cover of the screen. During the two months which Stillger spent in the line, it
was necessary to request a reduction of smoke in his sector on only two occasions. At the rear it was a different story. After fighting in the mountains of southern Italy, the average infantryman felt uncovered on the Anzio plain and welcomed the concealment of smoke haze.53
While the large area screen at Anzio was not as decisive as some commentators would have one believe—“It [the mechanical smoke generator] probably saved the Anzio beachhead. ...”54—its value was nonetheless considerable. General Truscott commented on the effectiveness of the smoke, which was used extensively “to limit German observation and reduce the effectiveness of their artillery fires.”55 German sources after the war testified to the effectiveness of the “well prepared and conducted” screening operations at Anzio which obstructed observation and interfered with defensive and direct fire.56 Perhaps the situation was best summed up in the observations of Bill Mauldin’s incomparable Willie and Joe.
The Invasion of Southern France
With the successful completion of the Sicilian operation in the summer of 1943 the Seventh U.S. Army became nonoperational, its headquarters reduced to caretaker status.57 Then in January 1944 Allied Force Headquarters directed it to form a planning group for an operation against southern France to be mounted sometime in the following May. After considerable debate at the highest echelons DRAGOON (it was first called ANVIL) was given a definite time, place, and implementing force. These were 15 August 1944, a series of beaches east of Toulon, and Seventh Army’s VI Corps.58 The corps got three experienced infantry divisions for the operation, the 3rd, 45th, and 36th.
Because of the mountains bordering the narrow beaches of the assault areas, the enemy could have excellent observation of the landing
“My God! There we wuz an’ here they wuz.”
force. Cognizant of the terrain and with the experience of Salerno and Anzio behind it, the Navy was eager to screen the assault force and anchorage from artillery fire and bomber aircraft. Its smoke plan, drawn up to provide concealment for beach and bay, was quite complete. Each Navy and merchant vessel had several means of producing smoke—with smoke pots, liquid smoke, and fog oil for the Besler generators furnished by Seventh Army’s Chemical Section.59 CWS troops attached to the assault divisions were prepared to land at H-hour, screen the flanks of the several beachheads, and be ready to conceal the assault boats in case of offshore winds. Once the landings were secure these CWS parties, under control of the engineer shore groups, would be ready to shield supply dumps and anchorage from air attack.60
The smoke troops again were to come from a chemical decontamination company, this time the 21st. On 25 March 1944 the unit’s 2nd Platoon moved from Palermo to a beach near Oran, where it was attached to the 40th Engineer Combat Regiment to prepare for the invasion. Practice in assault landings and in the erection of beachhead smoke lines constituted the bulk of this unit’s training. In turn, the Engineers gained the experience of working in a haze limiting visibility to fifty yards. By June the platoon rejoined the 21st in Italy where it passed on its recently acquired amphibious experience to its three sister platoons.61
During the last weeks of July and the first week of August the three divisions which were to make the assault and their supporting troops underwent brief but effective practice for the appointed task.62 The culminating point was a full dress exercise in which the conditions expected on the beaches of southern France were realistically duplicated. Live ammunition, beach obstacles, and smoke screens helped to achieve authenticity.63
The 1st Platoon, 21st Decontamination Company, received an extra amount of training because the 3rd Division had detailed plans for the use of ground smoke during the initial phases. The additional work for the platoon, and for a detail of two officers and thirty enlisted men from the 3rd Chemical Mortar Battalion which augmented the division’s smoke troops, was aimed at producing physical hardness, self-reliance, and proficiency in tactics of the infantryman.
The 3rd Division’s target area was the St. Tropez Peninsula. Elevations here reached 1,000 to ‘,500 feet, providing the defenders with excellent observation of the sea, the beaches, and the narrow strip of wooded dunes. The 3rd Division’s assault areas on the peninsula, designated Red Beach and Yellow Beach, were both flanked by capes, a situation which enhanced the possibilities of German observation and provided the motive for the flanking screens of the attacking force. But if the terrain was unpropitious, its defense was another matter. Intelligence sources indicated that the enemy would not defend the area too strongly because of commitments in northwest France. Moreover, the rather skimpy fixed defenses of the area were manned by non-German and limited service troops.64
Preceded by heavy naval and air bombardment the VI Corps landed on 15 August against light resistance. During the actual assault the Navy used smoke only in the 3rd Division sector. Here smoke pots and generators in landing craft screened the flanks of the boat lanes and concealed incoming craft from enemy fire. Each of the four smoke details, two per beach, was to land at H-hour in an LCT. Training trials had demonstrated that under favorable conditions the detachments with their allotments of 1,200 M1 smoke pots could unload in about five minutes. It was hoped that the final stage of the trip to the beach would take place in specially buoyed medium tanks which were on the LCTs. If this were not possible the pots were to be floated ashore in rubber boats, or, in an extreme case, the packing boxes
with the pots enclosed could be tied in tandem and towed ashore by hand.
The smoke detail on the left flank of Red Beach was led by Lt. Frank J. Thomas, commanding the 1st Platoon, 21st Company. According to plan, four amphibious tanks carried the men across the beach to the railroad about 150 yards beyond. Fanning out to four positions at 100-yard intervals, the detail began operations within ten minutes of landing. The smoke line was gradually pushed inland to a road 250 yards from the beach. Until this time the smoke troops had not received enemy fire, but now mortar and small arms fire caused one casualty. No casualties were suffered in the heavily mined woods through which the smoke troops passed to reach the road.
The detachment from the 1st Platoon, which landed on the right flank of Red Beach, was led by Capt. Sam Kesner, assistant chemical officer of the 3rd Division. For some reason the landing craft dropped its amphibious tanks some 1,000 yards from shore. Consequently, Kesner’s party, which remained in the LCT, had to unload its pots the hard way. Some were thrown into two 6-man rubber boats and towed to the beach. The rest of the smoke munitions were tossed overboard and floated ashore in their crates, an expedient made necessary by the pressure of enemy small arms fire. The situation was made more difficult because the LCT had landed 400 yards to the right of its assigned area in order to avoid mines. The smoke plan called for four positions on the beach, a number soon increased to twelve because of the adverse winds. The smoke detail soon pushed inland about 100 yards, suffering four casualties in the early hours.
The two smoke details in 3rd Division’s Yellow Beach came from the 3rd Chemical Mortar Battalion. Each of the one officer—fifteen enlisted men details landed at H-hour, meeting conditions not unlike those found on Red Beach. Because of the offshore mines, the LCT carrying the right flank party beached south of the assigned area. The group worked northward into position using smoke grenades for concealment from small arms fire. Opposition was heavier near the center of the beach but the smoke screen helped to eliminate observation, with the result that enemy fire became erratic, ceasing about H plus 30 minutes. The total length of the two screens on Yellow Beach was 2,000 yards.
Although the smoke mission for DRAGOON was extremely well planned and executed there was still room for improvement. Captain
Kesner felt that the eggs should not have been placed in so few baskets—that a larger number of craft should have carried the members of the smoke details during the assault. In this way the sinking of any LCT would not have been an irreparable disaster. Maj. Albert L. Safine, Chemical Officer, 3rd Division, suggested that in landings where enemy opposition would be substantial (resistance at DRAGOON was weak) the smoke detail should land at H plus 30 and that the equipment include amphibious mounted generators.
Smoke in Normal Forward Area Operations
In the struggle for Italy it seemed that the dice were always loaded in favor of the defense. As a rule the German defenders controlled the high ground which typified the Italian terrain and thereby kept the Allies under excellent observation. Such a situation called for a considerable amount of smoke.
There were several methods for laying smoke under such circumstances. The firing of artillery smoke shells upon enemy observation points was an old technique, abetted by the introduction of the efficient 4.2-inch mortar. The trouble in Italy was the abundance of observation points, making the blanketing of all of them impracticable. Another method of preventing enemy observation was the somewhat difficult job of placing a curtain of smoke between the opposing forces. More feasible was the covering of friendly positions and movements by smoke, a technique obviously requiring emplaced rather than projected smoke. Smoke pots were immediately available for this type of mission, although the harassing, if not toxic, nature of the HC filling hardly commended them for extensive or extended use. More often a combination of pots and shells was used. To illustrate, early on the morning of 13 October 1943, as VI Corps’ 3rd and 34th Divisions attacked across the swift moving Volturno River, the 2nd and 84th Chemical Mortar Battalions routinely fired smoke shells on enemy observation towers in the distant hills. More unusual was the detail from the 84th Battalion which manned smoke pots for the concealment of bridging sites and exposed approaches. The mission was not uniformly successful. On the evening of 13 October, for example, smoke pots set off to conceal bridge building activities drew enemy artillery fire to the area, a circumstance which made construction impossible. Even though smoke in some cases, particularly in inadequate
amounts, could thus be a mixed blessing, Company ID, 84th Chemical Mortar Battalion, kept alerted a 200-man detail equipped with 1,000 smoke pots to cover bridge sites.65
Another example of a screen formed by pots and shells occurred in mid-January 1944. II Corps captured the high ground east of the Rapido River and began to move up troops and supplies in preparation for an assault crossing. Because the main supply route, Highway No. 6, passed through relatively level terrain, it was exposed for a considerable distance to observed artillery fire from enemy positions on the mountain heights beyond the Rapido.66 On 18 January troops from the headquarters of the 2nd Chemical Mortar Battalion, under the supervision of Colonel Burn, II Corps chemical officer, screened a section of the highway with M1 smoke pots. At noon this force was supplemented by three smoke pot stations manned by troops from one of the firing companies of the battalion. During that day more than 1,000 enemy shells fell into the screened area with practically no damage and little interruption of traffic. Although the smoke interfered with the observation of American artillery, the corps commander considered the screen essential, and an entire company of the 3rd Battalion went forward with 185 tons of smoke pots.67
These two examples demonstrated the need that existed for concealment in the forward areas in Italy and the immediate steps taken to adapt the smoke pot to the large area mission. These initial attempts, while generally successful, called attention to the possibilities of the use of the mechanical generator in similar situations—possibilities which were soon to be realized.
Smoke on the Garigliano
On 9 March the 88th Infantry Division relieved a British unit on Fifth Army’s extreme left. The sector included the area southeast of the town of Minturno where Highway No. 7 crossed the Garigliano not far from where the river emptied into the Tyrrhenian Sea. About
Effect of smoke curtain, Italy. Bridge site before screening
Effect of smoke curtain, Italy. Same bridge after screening, with background obliterated
Carrying smoke pots into position in the Rapido River area
five miles up the coast stood Mount Scouri which, with the hill masses above Minturno, provided the Germans with excellent observation of the road network in the valley. Particularly vulnerable was Highway 7 along which passed all troops and supplies for the II Corps front. The British had used smoke pots around the river’s main bridge, a practice continued by American troops. On 28 March the 172nd Smoke Generator Company, recently freed from duty at Naples, undertook the large area smoke mission in this area.68 The new smoke installation also centered on the bridge. (Map 5) This vital point was encircled by a ring of 10 smoke pot positions having a 200-yard radius. The nucleus of the screen was a circle of mechanical generators 600 yards from the bridge. Just offshore, generators in small craft lent substance
Map 5: Smoke along the Garigliano, April 1944
to the left flank of the screen, an expedient made necessary by the prevailing onshore winds.
In an effort to nullify the effectiveness of enemy artillery each generator had three prepared positions. Under cover of darkness the crews moved their generators from position to position always eschewing regularity and pattern in a generally successful attempt at hiding exact locations. The area between the river and the enemy lines was dotted with other pot and generator positions picked primarily to deny observation between the bridge and Minturno. The most advanced of
these were within 500 yards of the enemy and about 200 yards beyond friendly infantry strongholds. Lesser installations concealed other bridges over the Garigliano and road junctions and portions of the highway farther to the rear. From his post at Minturno a smoke control officer supervised the installation, regulating the emission of smoke so that a uniform haze was maintained during all daylight hours as well as during moonlight nights and nocturnal air raids.
In this its first forward area mission the 172nd Company quite naturally met with problems not found in rear area screening. For one thing, the unit worked in two shifts because of the necessity of a constant daytime screen as well as the possibility of operations at night. (Installations at the rear, it will be remembered, did not include smoke among their daytime antiaircraft defenses.) The problem of security was greater because of the danger of enemy patrols. Communications maintenance increased appreciably and the need for continuous fog oil resupply in an area both difficult and dangerous to reach involved problems unknown at the port screen at Naples.
Large Area Screening in Northern Italy
Stymied by swift German reaction to Operation SHINGLE (Anzio) on one hand, and by the strong Gustav Line on the other, the Fifth Army did not capture Rome until early June 1944. Later that summer, the much debated invasion of southern France became a reality and drew off in the process a large part of Fifth Army strength, in fact, the entire VI Corps. Six of the nine CWS companies capable of smoke operations were included in the departing force; remaining were the 172nd and 179th Smoke Generator Companies and the 24th Chemical Decontamination Company, the latter experienced in smoke operations but soon diverted to chemical depot operations. As a result, the means to pursue a successful forward area smoke mission were seriously impaired, especially when the recently won ports of Civitavecchia, Piombino, and Leghorn were requiring what were to be the last vestiges of port screening in the Italian campaign. By September the 172nd and 179th were released from the Leghorn operation and placed in support of II and IV Corps, respectively, attachments which were to last until the end of the war.
That same month saw the beginning of a concerted effort by the 15th Army Group to penetrate the Gothic Line to which the Axis
had withdrawn after the fall of Rome. The natural strength of this position, which crossed Italy between Florence and Bologna, combined with the weakened state of the Allied forces, resulted, after an initial Fifth Army penetration, in eventual stalemate.
During the first month of the offensive the 172nd Company concealed bridge sites on the Sieve and Santerno Rivers. In each case, accurate German artillery fire became ineffective once smoke was employed.69 The divisions in the II Corps sector at first made spectacular gains, reaching a point on Highway No. 65 above Livergnano within twelve miles of Bologna. Here the advance stopped, and there was to be little change in the front line until the following April. On the left shoulder of this penetration, strong German resistance denied Fifth Army Mount Adone and the hill mass at Monterumici, with the resultant variation on a familiar theme—from these vantage points the enemy retained direct observation of Highway No. 65, the main supply route for the section.70
In partial answer to this threat on the supply route, the 172nd Smoke Generator Company maintained a smoke line from 16 October 1944 until 14 April 1945. For 181 days, except when the weather made screening unnecessary or when II Corps for one reason or another needed perfect visibility in the area, the smoke haze concealed friendly movements along a 2-mile stretch of the highway. Periods of bright moonlight sometimes forced the 172nd to operate on a 24-hour basis.
Although the enemy was only about two miles away vehicles drove along the road without difficulty. The smoke was also of value to patrols and other troops moving across exposed areas. By reducing the danger and dread of observed fire the operation on Highway No. 65—the longest continuous forward area smoke screen in World War II—was both a material and psychological aid.
The 172nd, with some outside help, performed another important mission while at Livergnano. From 25 January to 27 March 1945 a detachment from the company screened the road network in the Sillaro Valley which supplied both the U.S. II Corps and British Eighth Army sectors. The most vital part of this network was the
Smoke screen conceals movements along highway
crossroads at San Clemente, the site of a smoke pot screen manned first by the 88th Division and then by British troops, since the capture of the town in October. The undesirable characteristics of the HC pots led to a successful January trial of a smoke installation featuring the recently developed M2 mechanical generator. Captured enemy patrols admitted the effectiveness of this installation which concealed vehicular traffic, troop concentrations, supply dumps, and artillery positions of American and British forces.
On the IV Corps front the 179th Company supported operations ranging from the Ligurian coast to the Serchio Valley and Highway No. 64. Because of the distance between these missions—in the IV Corps sector Highway 64 was over forty miles from the sea—the unit’s two platoons operated separately. The 1st Platoon, between Highway No. 1 and the sea, screened the coastal plain north of Viareggio. Detachments from the platoon were split off to fulfill other missions: screens for bridge sites and tank attacks and hazes for daylight patrols.
On 5 November, the 2nd Platoon began a 102-day haze to cover an exposed stretch of Highway 64, as well as several supply installations, in the right sector of IV Corps. Just as in the case of Highway 65 south of Bologna, before the haze daytime traffic on the road always drew fire. Afterward, the amount of enemy fire noticeably decreased, bridges were built and strengthened without interruption, and traffic passed with little interference.
As World War II began, the large area screen was designed to conceal rear area installations. American and British smoke units and equipment in North Africa successfully demonstrated the validity of this mission and the adequacy of the smoke munitions. Once the scene of fighting shifted to the mainland of Italy doctrine for large area screens saw a drastic expansion. True, the old mission remained—as witness the smoke installation at the Naples complex, the largest of its kind of the war. But added to this was the use of smoke in assault landings and during the more conventional type of front-line operations. The evolution of the front-line mission was dependent upon several factors. First was the peculiar nature of the terrain in Italy, where circumstances and geography conspired to have the Allied forces continually advance under the superior observation of the enemy and against his deadly fire. The second factor was the limitations of conventional front-line smoke munitions—artillery and mortar shells and the smoke pots. And last, the gradual diminution of the power of the Luftwaffe and the consequent lessening of the need for port screening released smoke units, never in abundance in Italy, for the fulfillment of the new mission.
Forward area screening encountered the stiff and legitimate objections of such diverse sources as the field artillery and the supporting naval units. The problem, of course, was observation. Smoke did contend with these effective and established elements, and CWS officers took great care to see that the nature of these smoke screens was complementing, not competing.