Barrels are standard storage devices for excavated oil, and are used to transport and temporarily store crude oil before transporting it to a refinery. Due to issues with storage, they are often scattered around the base, and due to the oil's flammability, pose an extreme danger if and when detonated.
Barrels are classified either as barrel racks (3 barrels as one "structure") or single barrels (colored orange like barrel racks, or grey). However, the explosion damage is the same for all barrels.
Be wary of those barrels of petrol! If damaged, they will surely explode violently. Perhaps we can use them to our advantage.
—Soviet EVA warning the player during Operation: Bleed Red
Barrels are found frequently in the campaign. Due to their significant impact in certain missions where they appear (for instance making a base more vulnerable than it should be), Barrels are often a running gag that is recognized by the community.
Their explosive damage can be advantageous to a player if there are barrels near enemy troops and buildings. By ordering troops to fire at barrels, it would cause a spectacular chain reaction and destroy multiple enemies. However, the player should be wary not to put their own forces too close to barrels (especially units critical to the mission like heroes).
- In Side Effect, the initial Pacific Front attack forces destroyed a Russian outpost by detonating large amounts of barrels in it.
- In Recharger, the Allied bases are full of barrels, which makes them very easy to be destroyed.
- Shortly before the player is given command in Think Different, Chinese forces will destroy a Pacific Front base by blowing up the barrels in it, destroying several oil derricks in the chain reaction.
- In the Covert Ops mission Eclipse, shortly after the player has established a base, Three Future Tank X-0s will arrive from the west and destroy the Infiltrated Pacific Front outpost by blowing up the barrels in it.
- At the beginning of Death From Above, the player can target the barrels in the Niihau island Allied outpost to destroy it easily.
- In Singularity, shortly after the player has contacted the Psicorps Trooper, three Attack Dogs will emerge from the kennel to attack the player's force, but the barrels nearby explodes, killing the dogs. A Pyro is alerted, but reports that the dogs "are doing their business with the barrels". Barrels are also placed near walls and mission buildings.
- Prior to The Conqueror, the Infiltrators put some barrels near the Nuclear Reactors, which makes the Shadow Tanks available to destroy the reactors simutaneously.
- In Awake and Alive, the Colonels rescue the Soviet General by detonating a barrel outside the cell, which wipes out the guards. After the General and his men arrive at the second bridge, there will be a blockade at the end, which is full of barrels. In order to continue, the player must lead a Crazy Ivan to sneak through the blockade and blow up these barrels.
- In Divergence, the Power Plants which are powering the Prism Towers are full of barrels. They must be taken out by either creating Brutes on the bridge or ordering Malver to sneak through the towers and detonating the barrels.
- In Juggernaut, the Chinese ally's outposts are full of barrels, which will make them very easy to be defeated.
- In Dance of Blood, the pink-colored ally's outposts are full of barrels, which will make them very easy to be defeated.
- In the Covert Ops mission Fullmetal, the Allies destroyed a PsiCorps base by detonating barrels in it, and they set a base on the ruins and satirized them "They really should learn how to store those oil barrels properly".
- In the Covert Ops mission Survivors, barrels are placed next to most Mind Readers, which allow them to be safely destroyed by Malver.
- In Unthinkable, the friendly forces' bases are full of barrels, which will make them very easy to be defeated.
- In the Covert Ops mission Brothers in Arms, the Nuclear Reactors in the first part of the mission contain barrels, which allows Reznov to safely destroy them.
- In Kill the Messenger, the Revolt destroyed a Chinese outpost by detonating barrels in it, and they set a base on the ruins.
- In Cyberanatomy, when two colonels and the Saboteur move to the southwest zone, the Saboteur will move a barrel out the walls, which will make the colonels available to clear the way by detonating it.
- In the Contagion Challenge, green barrels (both single and barrel racks) appear that release poison clouds when destroyed.
- In Devoted, some barrels are placed next to the Psychic Amplifier. Their explosion can take it out at full health.