Wis. Stat. § 285.19
Any duly authorized officer, employee or representative of the department may enter and inspect any property, premises or place on or at which an air contaminant source is located or is being constructed or installed at any reasonable time for the purpose of ascertaining the state of compliance with this chapter and s. 299.15 and rules promulgated or permits issued under this chapter or s. 299.15. No person may refuse entry or access to any authorized representative of the department who requests entry for purposes of inspection, and who presents appropriate credentials. No person may obstruct, hamper or interfere with any such inspection. The department, if requested, shall furnish to the owner or operator of the premises a report setting forth all facts found which relate to compliance status.
Wis. Stat. § 285.19