Damage over time is a form of damage in the Battlefield series whereby the player suffers light damage at regular intervals. It typically corresponds to exposure to a hazard, such as fire, poison gas, or water. It is distinct from "impact damage" inflicted by most firearms and melee weapons, "blast" or "splash damage" from explosives, and "collision damage" handled by the physics engine. Weapons capable of inflicting damage over time can be useful for area denial.
Damage over time in Battlefield 2 (and possibly Battlefield 1942 before it) is limited to rollover damage for most ground and naval vehicles, as there are no purposeful means to turn vehicles back upright. (Vehicles may be turned back over through collisions with other vehicles, and possibly explosives.)
Certain environmental fires may deal damage over time to the player.
Battlefield 4 introduces the Incendiary Grenade for infantry and Gunner Incendiary launcher for vehicles, both of which inflict damage over time. The Phantom bow is capable of firing Poison Arrows, although they cannot kill enemies solely through damage over time.
Players who dive underwater will eventually take damage over time if they stay submerged too long.
Vehicles no longer take damage when disabled, but may still do so if overturned.
Battlefield 1 has a larger selection of weapons and vehicle equipment that can inflict damage over time:
Players caught on fire also take "afterburn" damage after the player leaves the area. This damage increases when the player sprints, and is reduced and shortened when the player goes prone. Afterburn is not stopped by swimming. Vehicles also take slight damage over time from sources of fire.
Players caught in gas clouds can equip the Gas Mask to counter its effects, at cost of impeded vision and the inability to aim down sight.