TearGas and HalonGas (damage types)

TearGas (tear gas) and HalonGas (halon gas) are damage types in Deus Ex with multiple properties in common. "TearGas" damage is caused by gas clouds emitted by the gas grenade and the pepper gun. "HalonGas" damage exclusively comes from gas clouds emitted by the fire extinguisher. "TearGas" and "HalonGas" are internal names that only appear in game files.

Effects on non-player characters

 * Tear gas and halon gas cause non-player characters (NPCs) to be stunned and blinded. NPCs that are stunned and/or blinded do not retaliate against the player. "Stunned" and "blinded" are separate afflictions. However, both occur when an NPC is hit by tear gas or halon gas.
 * Stunned enemies receive 4x the damage that they would otherwise take, except that the multiplier for stealth attacks does not apply to stunned targets.
 * Blinded enemies do not perceive the player, and undergo an eye-rubbing animation.
 * Tear gas and halon gas inflict no actual (health) damage to NPCs. Therefore, these damage types are only capable of stunning and blinding NPCs, and are not capable of killing them or rendering them unconscious.
 * The "stunned" and "blinded" effects do not apply to animals, robots, and the player character.

Effects on the player character

 * Tear gas inflicts damage on the player character at a rate of 2 HP per second for each gas cloud that is affecting the player.
 * The player can by affected by multiple gas clouds simultaneously, in which case the player would take more than 2 HP of total damage per second.
 * When the player takes damage from tear gas, the HUD will display a green indicator icon.
 * Halon gas inflicts no damage to the health of the player character. However, the game will still play a sound effect and display a blue "O2" damage indicator icon if the user steps into a halon gas cloud.

Other properties

 * Halon gas will extinguish the "on-fire" burning effect.
 * Due to an oversight, halon gas can cause grenades to explode.

Resistance

 * Non-transgenic animals receive no damage from tear gas and halon gas. However, tear gas and halon gas will cause the animal to flee.
 * Robots and transgenic animals are fully immune tear gas and halon gas.
 * MJ12 Commandos and riot cops are fully immune to tear gas and halon gas.
 * For the player, resistance is provided by Hazmat Suits and the Environmental Resistance augmentation. The only effect of resistance in this context is reduction of damage caused by tear gas. Since actual damage is truncated to the nearest integer, it is possible to fully eliminate the damage taken from tear gas.

TearGas

 * Gas grenade
 * Pepper gun

HalonGas

 * Fire extinguisher