Corrosive gas environment wiring

[TheBIGVP.]

I have to replace the wiring at my wastewater treatment plant "headworks" (where the raw sewage enters the plant) due to the corrosion of the wiring from the corrosive Hydrogen Sulfide gas inherent with raw sewage. The copper THHN stranded wiring is corroding and breaking off rather easily.
Is there a suitable wire, protective spray, etc that meets code requirements and works?
Thanks in advance!
Vince

 

[tom baker]

Hoffman makes a vapor capsule that inhibits corrosion, size used depends on volume. Same product is available in spray can.