
Up to 1000 pollution, no damage. For each 100 points beyond that, does 1 point of damage per second and gives a chat message. I set up configuration variables at the top of control.lua so it should be easy to change these to taste.
0.0.2: Finally updated for 0.14.21 with damage type changed to acid (so armor reduces damage), and set up only to affect online players in multiplayer games (I have not tested this, only single player.)
0.0.3: Updated for 0.15.3.