Joists have mold, as well as the duct work exterior
Mold on exterior duct work
Mold on joists and duct work
Moisture creates mold
Proper ventilation is needed to keep mold out. Water intrusion from the exterior is creating an issue.
The joists have been worked on and treated with anti-microbial product
Duct work is free and clear of all exterior mold
The crawl space is clean and treated
Pre-remediation of mold
Previously duct was covered with mold
Crawl spaces can harbor mold, have you checked yours lately?