Residents of Ringle, Wisconsin are starting to see mold growth inside homes damaged in last week's tornado, and an environmental testing firm is urging anyone entering those structures to wear an N-95 respirator and treat damp drywall and insulation as a respiratory hazard, WSAW reported on May 1.

Dave Barrett, operations manager at NorthStar Environmental Testing, told the station that mold growth is normal after a building takes on water and is not in itself a reason to panic, but said homes should be aggressively dried out, often by professional remediators using antimicrobial treatments. He recommended air sampling using spore-trap analysis to assess indoor air quality, and pointed homeowners to the EPA's mold guidance for cleanup standards.

Volunteers in Ringle, including a group from Co-Vantage Credit Union, have largely confined their cleanup work to yard debris outside the homes to limit exposure, with masks, eye protection and gloves as standard kit. One Ringle homeowner told WSAW she can smell mold in her damaged home and is keeping her family out of it until it can be torn down.