Radioactive Contaminants

Radioactive Contaminants is a disease category encountered in radioactive environments of Oxygen Not Included. It appears on Radioactive Biome tiles and on asteroids with radioactive regions such as Radioactive Ocean Asteroids. These environments are presented as distinct map features and space points; some radioactive asteroids are reachable via the Teleporter or appear as Space Biome points on the star map. Radioactive locations can include specialized vents (for example, Infectious Polluted Oxygen Vents) that release contaminated gas and contribute to spread.

Exposure to radioactive contamination is most commonly an environmental hazard tied to the tiles and vents of these biomes rather than a craftable or containerized item. When planning expeditions to asteroids with radioactive zones, note that certain Radioactive asteroids (for example, the radioactive ocean variants and some flipped asteroids accessible by Teleporter) do not contain Reed Fiber; this prevents building Atmo Suits on those locations until a later mission that provides reeds or Dreckos. In those early expeditions, duplicants must rely on Oxygen Masks to avoid suffocation and to operate while managing radioactive hazards.

Radioactive Contaminants interact with other pollution systems in the game and are affected by storage and liquid coverage rules. Polluted Dirt — a common carrier of polluted gases — emits Polluted Oxygen over time if stored at pressures below 1.8 kg/tile, and that emission can act as a vector for infectious or polluted atmospheres in adjacent tiles. Submerging Polluted Dirt in a liquid or storing it under a gas pressure of at least 1.8 kg/tile prevents those emissions. In the Spaced Out DLC, emission rates from stored polluted materials are reduced by a factor of 10 to limit rapid atmosphere buildup on asteroids that yield large amounts of Polluted Dirt.

Sources and sinks relevant when managing radioactive contamination include many production and biological processes that generate polluted materials: Outhouses, Ethanol Distillers, Water Sieves, certain farmed creatures (Pacus and variants), and waste-processing buildings such as the Sludge Press. Polluted Dirt can be converted back into Dirt in a Compost, consumed by creatures like Sage Hatches (which excrete Coal) and Pokeshells (which excrete Sand), or used in machines such as the Sublimation Station to produce Polluted Oxygen; these pathways affect how contamination accumulates or is recycled in a base.

Practical considerations

• Expect limited local Atmo Suit production on some radioactive asteroids; bring Oxygen Masks for initial colonists.
• Contamination spread is reduced by keeping polluted solids submerged or stored under >= 1.8 kg/tile gas pressure.
• Treat vents and anomalous gas sources in radioactive biomes as potential points of infectious gas release and plan ventilation and airlocks accordingly.
• Use composting, biological consumers (Sage Hatches, Pokeshells), and processing machines to convert or contain Polluted Dirt produced by base industry and exploration.
• In Spaced Out DLC play, stored polluted-material emissions are an order of magnitude lower, easing storage management on large asteroid yields.