Cloud

The Cloud is an airborne toxin covering the Sierra Madre Casino & Resort.

Pre-War
Created as an experiment by the Big MT execs, the Cloud is a product of the Z-43 innovative toxins plant located in the crater, planned as a security mechanism for the resort. The Cloud appeared the first time when the villa ventilation system broke, poisoning nearby construction workers. Sinclair negotiated with Big MT executives for hazmat suits to explore the ventilation system for repair attempts. The team found the source of the problem in the main ventilation pipe, and returned to seek medical attention for exposure, cutting themselves out of the suits with Cosmic knives.

Post-War
After the war, the Cloud enveloped the area, blocking out the sun. Individuals known as ghost people inhabit the area, wearing the hazmat suits.

Father Elijah heard about the Cloud and planned to weaponize it in an attempt to destroy the New California Republic and wipe out all life in the Mojave. He states his goal as "wiping the slate clean" using the Cloud, making the Mojave "like it was meant to be... undisturbed by man."

Gameplay
The Cloud covers the casino, poisoning those who inhabit the area. It is described as smelling like copper, sulfur, or Old World gold, and Father Elijah states it "burns the lungs and seeps into the skin." Elijah mentions that he does not know its origins, stating that it may be from pre-War industrial pollutants or something in the Sierra Madre structure. He says that it is unique in the wasteland, and has kept the casino preserved since the Great War. The Cloud can decay Saturnite and Cosmic knives.

The Cloud causes coughing, dizziness, vision changes, internal damage, and death. It enters through the lungs and skin, causing damage with prolonged exposure. In some areas, the Cloud is concentrated, and these pockets cause more damage. Elijah states that he has "found fighting it useless" as rebreathers and chemical suits are not effective means of protection. Air indoors is safe to breathe, sheltered from the Cloud. The Cloud's concentrations can be used in manufacturing weapons, tools, or used in consumables such as Jar of Cloud residue. Sierra Madre martini adds to the Ghost Sight recipe with Survival 25.

Large concentrations of the Cloud block off areas of Puesta del Sol and Salida del Sol. The former can be cleansed at the Puesta del Sol switching station during the Mixed Signals quest. Salida del Sol South can be cleared by using the terminal near Dog's position and resetting the fans. Afterward, the Cloud in the streets disperses, though it remains in pockets in some rooms, and the area outside the neighborhood is unaffected.

Appearances
The Cloud appears It is mentioned