The Veil system was created by the Mountain Men. Located within the Mountain, its chemical containment and dispersal units allowed them to create a billowing mass of the lethal fog like vapors shrouding large areas of the outside, which could be used as a defensive weapon against outside threats.
The acid fog can be avoided by sheltering in caves higher than their entrance, by getting within an enclosed space, or more surely, by fleeing the area.
- Fog-like occurrence - Acts much like regular fog does in areas.
- Radiation Storm - Occurs like a tornado/rainstorm and sweeps areas very quickly.
Throughout the SeriesEdit
In Earth Kills, the Acid Fog is deployed at nighttime while Trina and Pascal are trying to make their way back to the Delinquents' Camp. The fog confuses and alarms the two who are consumed and killed by it. The next day, while Clarke is leading a group to get seaweed to treat Jasper's injuries, they hear a Grounder foghorn, spot birds suddenly flying away in alarm and then a strange-tornado like fog bank that chases them. Clarke, Finn and Wells Jaha hide in an abandoned vehicle from the fog while Bellamy and Charlotte hide in a cave and the Delinquents, feeling some of the less lethal effects of the fog, seal themselves in their dropship. However, Atom is caught in the Acid Fog and severely burned. Unable to save him, Clarke mercy kills Atom to end his suffering.
In His Sister's Keeper, Lincoln blows his foghorn to end the Grounder ambush of the Delinquents, causing both sides to think Acid Fog is coming. While the Grounders flee, the Delinquents hide under a tarp until they realize that it was just a false alarm. Finn later realizes what Lincoln did after spotting his foghorn.
In Fog of War, while listening to a radio transmission from the Mountain Men, Raven Reyes and Chancellor Griffin discover that the Mountain Men have been deploying the fog as a weapon, which they refer to as the Veil.
During the Mount Weather War the system protected Mount Weather from the Coalition/Sky People force keeping them at bay until Bodyguard of Lies when Bellamy Blake destroys the control room for the fog, rendering it useless.
Mild exposure results in blistering skin and causes coughing. Exposure lasting more than a minute or two, however, causes extreme pain, blindness, paralysis, and eventually death.
According to Raven Reyes's notes, the Acid Fog is assumed to be part nerve gas part sulfur mustard vesicant (military chemical warfare agents). Exposure to these chemicals can cause paralysis, skin blisters and burns, and respiratory effects.
Symptoms may include loss of consciousness, convulsions, cessation of respiration, Flaccid, Paralysis copious nasal and oral secretions. Intense bronchoconstriction. Decontaminate within 2min to prevent tissue damage.
The acid fog has killed numerous outsiders. Known victims include: