Wis. Admin. Code Department of Natural Resources NR 664.0120
No later than 60 days after completion of the established long-term care period for each hazardous waste disposal unit, the owner or operator shall submit to the department, by registered mail, a certification that the long-term care period for the hazardous waste disposal unit was performed in accordance with the specifications in the approved long-term care plan. The owner or operator and a qualified professional engineer shall sign the certification. Documentation supporting the professional engineers certification shall be furnished to the department upon request until the department releases the owner or operator from the financial assurance requirements for long-term care under s. NR 664.0145(11).
Wis. Admin. Code Department of Natural Resources NR 664.0120