The experimental hazmat suit and hazmat darklight cowl were created at Big MT before the Great War. Described as an "experiment within an experiment", the new hazmat suits were issued to Sierra Madre Villa workers when the Cloud, a toxin also originating from Big MT, became a major problem for construction crews and to general health. Due to unforeseen interaction between the two experiments, the Sierra Madre Villa workers later mutated after the Great War. The ghost people were born, an atypical mutation and terrifying perversion of humanity.
The hazmat suit is known to be bulky and would grow stiff with use. It is not protected from corrosion; when exposed to the Cloud, the hazmat suit has to be opened with extremely sharp items like the cosmic knife. The hazmat darklight cowl has an integrated night-vision setting which makes the vision of the wearer lighter and green-colored. The eyepieces are bright yellow in the center and glowing green around. The cowl is also known to create difficulty when speaking. Despite its quality and its high protection against poison, the hazmat suit did not protect against the poisonous gas cloud of the Sierra Madre Villa which later became the Cloud.
Wearing the helmet will give you a night-vision effect. Unlike night-vision scopes, it does not turn off during the day. The effect is similar to Ghost Sight.
Unlike the suits used by the unfortunate Sierra Madre construction workers, the obtainable hazmat suit has practically no negative effects; it will not grow stiff in prolonged use, it actually protects the wearer against hazardous chemicals and poisons and the headgear will not affect speech in any way.
- Hazmat Testing Ground, the suit and the cowl can be found in a protected pod. The player must either find the Hazmat Pod Security Code or shoot the field with an upgraded sonic emitter to gain access to them.
- Wearing the cowl while viewing any ending slideshow will cause the night vision effect to persist throughout the slideshow.
- The suit, unlike the one worn by ghost people, has no gloves. This seems at odds with the intended purpose of the suit, which is to protect the wearer from hazardous materials in the environment. Additionally, the eyepieces of the ghost people's helmets glow solid green instead of bright yellow at the center and ringed with green.
- When equipped on companions, the eyepieces of the cowl will not glow.
- Using Ghost Sight or Cateye with the darklight cowl causes your night vision to get brighter.
- This suit cannot be obtained by using the glitch where you go into third-person mode and slowly rotate the screen so you can take things through walls; the option to take the suit is present, but when you attempt to take the suit nothing happens.