Answers

Hey Scott, 

I would say the best course of action would be to contact a certified mold remediation company and set up an inspection to determine if mold is present, because you never know what kind of mold it may be and it's better to be safe than sorry! 

Hope this helps!

Eric Consuegra, Arocon Roofing and Construction, LLC 

Contact an established mold remediation company.  Mold can be dangerous to your health and you don't want to take any chances.  We run into mold frequently due to just the situation you have.  As seen in the picture, oftentimes the airflow from the soffit into the attic is clogged with insulation causing humidity to be trapped in the attic.  This is another contributor to mold so make sure you don't also have this situation.  We always use a certified and credentialed mold company.  This is not an area you want to cut corners.

Scott,

The easiest thing to do is check in the attic and look at the sheathing. If there is any mold growth, you can tread it with a proper mildewicide and make sure that the fan ducting is extended to vent through the roof or through the side of the home (i.e. to outside).

Good time to check the venting of the roof in general as well as look into any air sealing and insulation.

Don't worry about the mold having spread to the home and points further than the attic...it will not have as a result of a poorly routed bath fan.

If you are concerned about the mold while accessing the attic, have proper PPE (personal protection equipment) on to include a respirator that is effective against mold spores.

Don't disturb them until you treat them.

So you think you may have mold,   then it a fairly simply solution....bring in the best people you can find and be on site when they do their walk thorugh and walk around with a pad of paper.  They are some of the best people in the industry. 

Philip Anderson

Berkeley Ca