Smoke grenades are canister-type grenade

Grenade

A grenade is a small explosive device that is projected a safe distance away by its user. Soldiers called grenadiers specialize in the use of grenades. The term hand grenade refers any grenade designed to be hand thrown. Grenade Launchers are firearms designed to fire explosive projectile grenades...

s used as ground-to-ground or ground-to-air signaling devices, target or landing zone

Landing Zone

A Landing Zone or "LZ" is a military term for any area where an aircraft can land.In the United States military, a landing zone is the actual point where aircraft land...

 marking devices, or as screening devices for unit movements. Smoke grenades are normally considered non-lethal, although incorrect use may cause death. The body consists of a sheet steel

Steel

Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...

 cylinder with a four emission holes on top and one on the bottom to allow smoke release when the grenade is ignited. The filler consists of 250 to 350 grams of colored

Colored smoke

Colored smoke is a kind of smoke created by an aerosol of small particles of a suitable pigment or dye.Colored smoke can be used for smoke signals, often in a military context. It can be produced by smoke grenades, or by various other pyrotechnical devices...

 (red, green, orange, gray, yellow, blue, white, black, or violet) smoke composition

Smoke composition

A smoke composition is a pyrotechnic composition designed primarily to generate smoke. Smoke compositions are used as obscurants or for generation of signaling smokes. Some are used as a payload of smoke bombs and smoke grenades.-Obscurants:...

 (mostly potassium chlorate

Potassium chlorate

Potassium chlorate is a compound containing potassium, chlorine and oxygen atoms, with the molecular formula KClO3. In its pure form, it is a white crystalline substance. It is the most common chlorate in industrial use...

, lactose

Lactose

Lactose is a disaccharide sugar that is found most notably in milk and is formed from galactose and glucose. Lactose makes up around 2~8% of milk , although the amount varies among species and individuals. It is extracted from sweet or sour whey. The name comes from or , the Latin word for milk,...

, and a dye

Dye

A dye is a colored substance that has an affinity to the substrate to which it is being applied. The dye is generally applied in an aqueous solution, and requires a mordant to improve the fastness of the dye on the fiber....

). The reaction is exothermic

Exothermic

In thermodynamics, the term exothermic describes a process or reaction that releases energy from the system, usually in the form of heat, but also in the form of light , electricity , or sound...

 and grenade casings will often remain scalding hot for some time even after the grenade is no longer emitting smoke.

Another type of smoke grenades are the bursting kind. These are filled with white phosphorus (WP), which is spread by explosive action. White phosphorus catches fire in the presence of air, and burns with a brilliant yellow flame, while producing copious amounts of white smoke (phosphorus pentoxide

Phosphorus pentoxide

Phosphorus pentoxide is a chemical compound with molecular formula P4O10 . This white crystalline solid is the anhydride of phosphoric acid. It is a powerful desiccant.-Structure:...

). These double as incendiary grenades, and a variant of these are also launched from infantry-portable or armored fighting vehicle-mounted grenade launcher

Grenade launcher

A grenade launcher or grenade discharger is a weapon that launches a grenade with more accuracy, higher velocity, and to greater distances than a soldier could throw it by hand....

s. Users must also be wary of wind direction when using smoke grenades.

Smoke grenades should not be confused with smoke bomb

Smoke bomb

A smoke bomb is a firework designed to produce smoke upon ignition. Smoke bombs are useful to military units, airsoft games, paintball games, self defense and pranks...

s, which are typically started with an external fuse

Fuse (explosives)

In an explosive, pyrotechnic device or military munition, a fuse is the part of the device that initiates function. In common usage, the word fuse is used indiscriminately...

 rather than a pin. Smoke grenades often cost around $40 USD

United States dollar

The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....

 compared to smoke bombs, which can often cost just a few cents. Smoke grenades generally emit a far larger amount of smoke than smoke bombs that are sold as fireworks

Fireworks

Fireworks are a class of explosive pyrotechnic devices used for aesthetic and entertainment purposes. The most common use of a firework is as part of a fireworks display. A fireworks event is a display of the effects produced by firework devices...

.

Use

Used to create smoke screens, the grenades can be used to provide opportunity for movement over ground covered by fire. Smoke grenades can also be used to signal aircraft. Thermal imaging is able to 'see' through smoke screens and, as such, fighting vehicles equipped with thermal imaging can use smoke to blind the enemy infantry while still being able to see them using thermal cameras.

Other uses

Smoke grenades are sometimes used in paintball

Paintball

Paintball is a sport in which players compete, in teams or individually, to eliminate opponents by tagging them with capsules containing water soluble dye and gelatin shell outside propelled from a device called a paintball marker . Paintballs have a non-toxic, biodegradable, water soluble...

 or airsoft

Airsoft

Airsoft is a sport in which participants shoot round non-metallic pellets launched via replica firearms.Gameplay varies in style and composition but often range from short-term skirmishes, organized scenarios, military simulations, historical reenactments, to competition target shooting events...

 events, though these are not necessarily of military grade. Some devices utilized for the purpose of generating concealing smoke are high-volume smoke candles.

Smoke compositions can be also used as an aerosol

Aerosol

Technically, an aerosol is a suspension of fine solid particles or liquid droplets in a gas. Examples are clouds, and air pollution such as smog and smoke. In general conversation, aerosol usually refers to an aerosol spray can or the output of such a can...

ization vehicle for other materials than dyes; popular applications are in dispersion of CN gas

CN gas

Phenacyl chloride is a substituted acetophenone. It is a useful building block in organic chemistry. Apart from that, it has been historically used as a riot control agent, where it is designated CN.-Preparation:...

 or more commonly CS gas

CS gas

2-chlorobenzalmalononitrile is the defining component of a "tear gas" commonly referred to as CS gas, which is used as a riot control agent...

, or in agriculture for dispersion of insecticide

Insecticide

An insecticide is a pesticide used against insects. They include ovicides and larvicides used against the eggs and larvae of insects respectively. Insecticides are used in agriculture, medicine, industry and the household. The use of insecticides is believed to be one of the major factors behind...

s.