Flip in Cape Coral, house built 2007.

This is sulfur corrosion from a failing HVAC coil, likely due to microbial growth or refrigerant issues. The black copper, sulfur smell, and darkened electrical wires indicate hydrogen sulfide (H₂S) or sulfur compounds corroding metal surfaces.

Immediate Concerns:

• Electrical safety: Dark wire ends suggest sulfur corrosion on connections—fire hazard. NEC 110.14(C) requires clean, secure connections.
• HVAC failure: Coil corrosion means ongoing contamination.

Real Remediation:

1. HVAC System: - Replace both evaporator coils (not just one). - Clean/flush the entire duct system—ACCA Duct Installation Standards 18 require clean ducts post-contamination. - Install a UV light or corrosion-resistant coating (per ASHRAE 62.1 ventilation standards).

1. Electrical: - Licensed electrician must inspect all boxes, outlets, and panels. - Replace any corroded wires/devices—NEC 300.6 mandates corrosion-resistant materials in corrosive environments.

1. Indoor Air Quality: - Test for mold (EPA guidelines). - Consider air purification systems.

Why Kilz Won’t Work: Kilz seals surfaces but doesn’t eliminate the source. Sulfur compounds will continue corroding new materials.

Bottom Line: This requires HVAC replacement, electrical rewiring, and duct cleaning. A licensed pro should handle electrical work. Painting over it is a temporary, unsafe fix.

This is Chinese drywall (CDW) off-gassing (hydrogen sulfide, carbonyl sulfide, carbon disulfide). The 2007 build date, Cape Coral location, blackened copper (copper sulfide), repeated coil failures, sulfur smell, and blackened wire insulation are the classic fingerprint. Kilz does not stop the gas permeation; it only masks odor temporarily.

Real Remediation (per CPSC & Florida DBPR guidance):

1. Total Gut: Remove all drywall, insulation, vapor barriers, and carpet/pad down to studs/framing.
2. Metal Replacement: Replace all copper refrigerant linesets, electrical wiring (branch circuits, NM cable), gas piping (black iron corrodes), fire sprinkler heads, and HVAC coils/air handlers. Do not reuse blackened wire (NEC 300.6, 310.10); sulfide corrosion continues under insulation.
3. Appliance/Plumbing: Replace water heaters, dishwashers, fridge ice makers, faucet supply lines, and toilet fill valves.
4. Cleaning: HEPA vacuum/HEPA air scrubbers during demo. Wet-wipe framing. Encapsulate framing with shellac-based primer (BIN/Zinsser) or specialized CDW sealant only after third-party clearance testing.
5. Verification: Post-remediation air testing (ASTM D5504/D6228) by a CIH or licensed FL mold assessor before close-in.

Code/Legal: FL Statute 553.899 requires disclosure. NEC 110.12(B) prohibits damaged conductors. This is not a DIY paint job. Hire a licensed CDW remediation contractor. Budget $80k–$150k+. Walk away if seller won't credit full remediation cost.