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Combat commanders refer to smoke as a two-edged sword. Smoke can assist a unit to succeed in battle or lead to its failure. There are many systems capable of providing smoke support: artillery, mortars, pots, grenades, aircraft, vehicles, and smoke generators. But only smoke generators are capable of providing a sustained, large-area smoke screen. This chapter will summarize the principles and applications of smoke in support of combat operations. FM 3-50, Smoke Operations, provides detailed guidance on the employment of smoke.

Smoke unit leaders must understand the enemy, how the Army fights, and how smoke functions as a countermeasure to sensors and enemy reconnaissance, intelligence, surveillance, and target acquisition (RISTA). Potential enemy forces, how the Army fights, and electro-optical systems/sensors are explained in great detail in other publications (See References).

This manual explains, in general terms, what the smoke unit leader needs to know about integrated smoke support (Chapter 1), explains the organizations and equipment available for generated smoke (Chapter 2), discusses planning and training necessary to engage smoke targets (Chapter 3). How to move and generate smoke is discussed in depth in Chapter 4. Chapters 5 - 6 outline the tactics, techniques and procedures for executing smoke support. Logistical planning considerations are found in Chapter 8.


In September 1944 the 84th Smoke Generator Company was hastily recalled from its transportation duties to support the XX Corps crossing of the Moselle River near the town of Arnaville in eastern France. At the site of the crossing in the narrow valley of the Moselle, a railroad, a canal, and the river roughly parallel each other in a 500 yard belt (figure 1-1). East of the river lay a strip of open land beyond which were occupied by the enemy. On clear days the Germans had observation of the Arnaville area from 5 or 6 miles down (north) the river and from 3 or 4 miles up (west) the valley.

In quest of surprise, the artillery plan stipulated that there would be no preparatory fire preceding the crossing. Instead, smoke from the 84th Smoke Generator Company was expected to conceal the crossing sites as dawn broke on 10 September. LTC Cottingham, 5th Division Chemical Officer, arranged for a meteorological study of the area. After a reconnaissance, LTC Cottingham and the company commander selected a line of positions behind Hill 303, some 2,300 yards west of the crossing sites (Position 1 on the map). They expected the prevailing winds to carry the smoke down the valley and over the river. Generators were not placed closer to the crossing site because of the "unlikelihood" of wind change and the inexperience of the soldiers of the 84th under fire. Smoke observation points were setup on Hill 331 (south of Arnaville) and Hill 303.


At 0115 on 10 September troops of the 1st Battalion, 10th Infantry began loading onto boats near the bank of the Moselle. They encountered only scattered small arms fire as they advanced over the open terrain across the river until daybreak, when the first German artillery fire began to fall. By this time the 2d Battalion had begun its crossing, assisted by the smoke from the M2 generators which opened up at 0600. Under this concealment, the wounded were evacuated from the far shore and supplies and ammunition were sent across to the embattled troops. By 0800, after close fighting and heavy casualties, the two battalions had taken two hills. Suddenly at 1000 the wind shifted, causing the smoke to disperse. As the smoke dissipated, enemy artillery concentrated on the crossing sites, which were now exposed.

Within an hour LTC Cottingham and LT Young, of the 84th, moved four generators down to the site of an abandoned railroad embankment (Position 2 on the map). Smoke pots helped conceal the generators as they began to build effective smoke, and by 1200 the crossing was again concealed. The Assistant Division Commander, BG Warnock, informed the Division Chemical Officer, LTC Nottingham, to keep the generators running continuously. LT Lamb, the company executive officer, was across the river conducting a reconnaissance for new emplacements, while LT Young continued to direct operations on the near bank. At this point, COL Greene, XX Corps Chemical Officer, joined LTC Nottingham to inspect the operation. At the fog oil supply point west of Arnaville, a group under the 1SG's control organized details to move generators and fog oil to the crossing site.

LT Lamb increased the number of positions to ensure that an effective screen might be maintained, regardless of the wind direction. Position 3 paralleled a short stretch of the Arnaville-Noveant road and was later augmented by a jeep-mounted generator which patrolled the road on the lookout for any gaps in the coverage. That night eight crews crossed the Moselle, dug in their equipment, and were ready to start operations at Position 4 at dawn on 11 September. The new plan also called for emergency Positions 5 and 6, located south of Arnaville, but these were never needed. The 84th continued to make smoke during daylight hours from 11 to 15 September, when the 5th Division captured the dominating hill in the area on the far bank.

The Arnaville experience demonstrated that smoke generators could give effective support to an opposed river crossing. The experience also served notice to chemical troops that certain improvements were desirable. The lessons learned on leadership, detailed planning, logistical support, training and rehearsal carry their messages home to present day operations.


Smoke and obscurants provide the commander with another means to defeat enemy forces and enhance force protection:

  • Degrading the enemy's ability to see.
  • Disrupting the enemy's ability to communicate.
  • Concealing friendly forces.
  • Deceiving the enemy.
  • Providing a means to identify and signal.
  • Degrading or defeating directed-energy weapons.
  • Enhancing friendly weapon system effectiveness.

Smoke can render some electro-optical target acquisition and sighting devices ineffective; degrade others significantly; and cannot affect some at all. Visual obscurants are used to defeat the enemy's battlefield viewers, such as binoculars, weapon sights, night observation sights, and laser range finders. Bispectral obscurants are used to defeat the enemy's battlefield viewers and weapon guidance systems such as command line-of-sight or terminal horning systems on antitank and air defense missiles. When developed, multispectral obscurants will defeat the enemy's battlefield viewers; weapon guidance systems; radar systems; and high-energy, microwave-directed energy weapons.


The primary factors that affect delivery of generated smoke onto a target are the weather and terrain conditions, the enemy, and command guidance.


Steering winds actually carry the smoke and determine its direction, speed, and downwind travel distance. Air stability affect the height, density, duration, and travel distance of smoke.

Since steering winds carry smoke, smoke usually follows the contours of the earth's surface. On flat, unbroken terrain and over water (open terrain), smoke streamers take longer to spread out and mix with other streamers. Obstructions, such as trees and buildings, tend to break up smoke streamers. The streamers may then re-form, cover a larger area, and create a more uniform cloud than over open terrain. Large hill masses and very rugged terrain cause strong cross currents of wind and tend to create holes and uneven dispersal of the smoke cloud. Appendix G provides detailed information on weather and terrain effects. See Appendix G and FM 3-6, Field Behavior of NBC Agents (Including Smoke).


Wind direction determines from where you will engage a target. However, making smoke from the optimal location to engage the smoke target may increase the risk of engagement by enemy forces. The intelligence preparation of the battlefield process should identify potential enemy units/positions. Smoke platoon leaders must consider the increased risk of hostile engagement and plan for additional security or modify the plan for engaging the target.


The supported unit commander must give planning guidance that answers the following questions:

  • What do I want smoke and obscurants to accomplish? (Degrade target acquisition? Conceal the movement of my main attack? Aid in deception?)
  • Where and for how long am I willing to sustain this smoke cloud? (Over my own position? Between my unit and the enemy? On the enemy?)
  • How much restriction in my own mobility can I accept? (Visibility 50 meters or less? More? Curtain only?)
  • How much restriction in my own target acquisition and engagement capabilities can I accept? (If I deny another's laser designators, I also deny mine, but my thermal sights are unaffected).
  • When might on-call hasty or deliberate smoke benefit me? (Where does my decision support matrix indicate I may be exposed and need immediate smoke to obscure the enemy?)
  • How will countersmoke help me? (If the enemy uses smoke, where and how should I retaliate with smoke to interfere with their synchronization?)


Smoke has four battlefield applications that support combat operations: obscuring, screening, protecting, and marking.

Obscuring Smoke

Obscuring smoke is smoke delivered directly on or immediately in front of enemy positions to blind or degrade their vision both within and beyond their location. Use obscuring smoke to attack and defeat enemy target acquisition and guidance systems at their source.

Screening Smoke

Screening smoke is smoke delivered in areas between friendly and enemy forces or in friendly operational areas to degrade enemy ground or aerial observation or both. It also defeats or degrades enemy electro-optical (EO) systems. In general, use screening smoke to attack enemy target acquisition and guidance systems by placing smoke between the friendly unit and the sensors.

Protecting Smoke

Protecting smoke is smoke used to defeat enemy guidance systems or to attenuate energy weapons on the battlefield. Smoke and obscurants have the ability to reflect, refract, or absorb energy. In an active nuclear environment or when threat of nuclear weapon use is high, use protecting smoke to attenuate the thermal energy from nuclear detonations.

Marking Smoke

Marking smoke includes smoke used to mark targets, identify friendly positions, and provide for prearranged battlefield communications.

The smoke generator platoon engages targets to either obscure, screen, protect, or mark. The mission profiles are as numerous as there are tactical operations (e. g., support for a combat unit in movement to contact; support for a combat service support unit that is sustaining a deliberate attack).


Smoke employed during offensive operations generally favor the attacker, however this is dependent on the situation. During offensive operations, smoke is used to--

  • Conceal maneuvering forces.
  • Provide tactical surprise.
  • Defeat enemy surveillance efforts.
  • Support deception efforts.
  • Enhance target acquisition.
  • Conceal breaching operations.
  • Allow the massing of forces.

Friendly smoke operations must increase friendly survivability and flexibility without degrading mobility and battle command. To achieve increased survivability and flexibility, use these guidelines:

  • Use proper movement techniques and formations.
  • Time smoke support with decision points.
  • Use unobscured weapons to overwatch.
  • Do not become silhouetted by your own smoke.
  • Engage the enemy through the smoke.
  • Plan for enemy countermeasures.
  • Plan for additional maneuver time under smoke.
  • Maintain situational awareness.
  • Know where the enemy is.


Smoke is used during defensive operations to disrupt enemy attacks and allow the commander to seize the initiative. Smoke is integrated throughout the battlefield framework to disrupt the enemy's synchronization. Smoke is used to--

  • Conceal disengaging and moving forces.
  • Slow and disrupt enemy movement.
  • Isolate attacking enemy echelons.
  • Conceal engineers emplacing obstacles and preparing positions.


Smoke effectiveness is based upon the amount of energy the smoke absorbs, reflects or refracts. Therefore, effectiveness is a function of the source electromagnetic energy and the properties and concentration of the smoke. Currently we can not measure the degree of smoke effectiveness. Therefore, the effectiveness of smoke is estimated by qualitative means called the visibility criteria.


The qualitative estimate of effectiveness, or visibility criteria, depends upon the smoke's ability to obscure in the visual portion of the electromagnetic spectrum. Currently, simple optics comprise 99 percent of all battlefield optics. Therefore, an estimate of effectiveness based on the visual spectrum is a fairly good representation of total smoke effectiveness. However, as more sophisticated sensors become widely available, and because our future countermeasures include hi-spectral and multi-spectral obscuration, future technologies will provide a means to accurately quantify the effectiveness of obscurants.

Visibility criteria categories are smoke haze, smoke blanket, and smoke curtain.

Smoke Haze

A smoke haze is defined as a concentration of smoke that would allow an individual to identify a small tactical vehicle between 50 and 150 meters away, but no farther than 150 meters. It is not dense enough to disrupt friendly operations within the cloud.

Smoke Blanket

It is a concentration of smoke that would allow the identification of a small tactical vehicle from 0 to 50 meters but no farther. A smoke blanket may hamper operations of friendly troops by restricting movement and activity within the screen.

Smoke Curtain

A smoke curtain is a dense, vertical development of smoke. It is placed between friendly and enemy positions to prevent or degrade enemy ground observation of friendly positions. Since the smoke curtain is not placed directly on friendly troops, it will not hamper friendly operations.


The only portion of the smoke effectiveness equation that the smoke platoon can control is smoke concentration. Controlling the smoke concentration is dependent upon the distance from point source to point source (spacing), weather and terrain conditions. Chapter 2 gives general guidance for spacing smoke generators.

Making effective smoke with smoke generators is more of an art and less of a science, and smoke control officers need to recognize that they must adjust spacing when there are radical changes in weather or terrain conditions (e, g., when the wind speed increases by more than 5 km/hr or when the unit transitions from open to wooded terrain). Table 1-1 provides a summary of the favorable and unfavorable conditions for generator smoke.

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