Pollution & Toxic Area Guide: All 22 Polluting Buildings & Cleanup

How Does Pollution Work on Kewa’s Back?

Because your settlement in Beyond These Stars sits on the living skin of Kewa, industrial waste does not simply blow off the edge of the map. Every smelter, mine, and chemical refinery deposits Pollution onto its own hex and neighboring tiles.

Left unchecked, pollution triggers a three-stage ecological collapse:

1. Soil & Forest Degradation: Polluted hexes lose fertility, turning lush grass barren and suffocating nearby crops.
2. Peep Sickness & Strikes: Peeps walking through or working on polluted tiles contract Sickness and suffer severe Happiness penalties (see Peeps Happiness & Strikes).
3. The 15-Minute Toxic Area Mutation: Any tile subjected to uncleaned High/Very High pollution for 15 minutes transforms into a festering Toxic Area that wounds Kewa directly.

Complete Table of All 22 Polluting Buildings (Ranked by Tier)

Before designing your industrial sector, consult this verified emission tier table covering all 22 polluting structures in Beyond These Stars v1.0:

What Is the 15-Minute Toxic Area Timer?

When pollution on a hex exceeds safe absorption thresholds and is not scrubbed by a Cleaner, a hidden 15-minute degradation timer begins ticking.

What Happens When a Tile Turns Into a Toxic Area?

• Impassable Blight: The hex erupts in purple-black toxic sludge. Standard roads across the tile break, severing Peep commute paths and Power Line routes.
• Kewa Carapace Damage: Each active Toxic Area drains Kewa’s Health and Happiness every minute, eventually causing Kewa to ignore your Strange Transmitter commands (see Kewa Care Guide).
• Contagious Spread: If the source factory keeps running while its own tile is toxic, emissions spill outward into the next ring of hexes, creating a chain reaction of Toxic Areas!

4 Proven Strategies to Contain & Clean Up Pollution

1. Deploy Powered Cleaners Before Turning On Heavy Factories

Unlocked via the technology tree, the Cleaner (10 Stone, 6 Copper, 4 Tools; draws 6 MW and 1 Peep) actively scrubs pollution from surrounding hexes.

• Rule of Thumb: Build 1 Cleaner for every 2 Medium/High polluters, and 1 dedicated Cleaner for each Very High polluter (Cement Factory, Battery Plant, Fuel Maker).
• Keep Cleaners Powered: Connect your Cleaners to a Battery-backed Power Grid so a brief solar dip never shuts off your scrubbers.

2. Use the Burner Generator 4-Empty-Hex Rule (-25% Pollution)

As detailed in our Building Adjacency Bonus Layouts, leaving 4 of the 6 hexes around every Burner Generator empty of buildings cuts its Medium pollution output by 25% immediately.

3. Plant Watered Forest Rings With Tree Nursery Saplings

Living Watered Forests do more than generate 4 tiles of breathable oxygen—they also act as natural bio-filters that slow down ambient pollution drift. Use Compost and your Tree Nursery (see Terraforming & Saplings Guide) to plant a dense green belt between your smelting district and your residential Huts.

4. Offload Dirty Extraction to Planetary Outposts

Once you launch Jose’s Scout Spaceship and unlock Planetary Outposts, you can shift heavy raw extraction (Trawlers for Shell, Blast Mines, and bulk smelting) onto uninhabited outpost worlds—keeping Kewa’s living back pristine and green!