Wis. Admin. Code Department of Natural Resources NR 664.0115
Within 60 days of completion of closure of each hazardous waste surface impoundment, waste pile and landfill unit, and within 60 days of the completion of final closure, the owner or operator shall submit to the department, by registered mail, a certification that the hazardous waste management unit or facility, as applicable, has been closed in accordance with the specifications in the approved closure plan. The certification shall be signed by the owner or operator and by a qualified professional engineer. Documentation supporting the professional engineer's certification shall be furnished to the department upon request until the department releases the owner or operator from the financial assurance requirements for closure under s. NR 664.0143(11).
Wis. Admin. Code Department of Natural Resources NR 664.0115