Class H vacuum cleaners are approved for highly hazardous dusts, such as mold spores, asbestos, lead, glass and mineral fibers, or carcinogenic fine dust. Their filter efficiency is at least 99.995%. Class H vacuum cleaners require secure filter changes, special bags, and regular inspections. They are only permitted to be used by trained personnel. They are required by law for particularly hazardous dusts in renovation, demolition, and industrial applications.