What exactly does a "Biohazard" damage flag mean on a vehicle?

A biohazard designation means the vehicle was flagged for contamination requiring specialized cleaning or remediation before it can be safely resold — most commonly bodily fluids from a medical event or fatality, but it can also apply to other hazardous contamination. By the time these vehicles reach auction they typically have undergone, or are slated for, professional decontamination, but the title and listing will continue to carry the biohazard note as a permanent disclosure. Always factor in extra due diligence and, where local law requires, professional cleaning verification before resale.