Radeon 9000/9200/9250 Users
If you are using the v1.4 patch and are still getting a black screen when entering a poison cloud, do the following.
1) Exit SiN Episodes.
2) Open Explorer and browse to:
C:\Program Files\Steam\SteamApps\[username]\sin episodes emergence\bin
3) Delete the dxsupport.cfg file and vidcfg.bin files.
4) Restart SiN Episodes.
You'll be good to go.