In the realm of environmental responsibility and compliance, the Illinois Department of Revenue PTAX-401 Pollution Control Facility Tax Return emerges as a crucial document for facility owners. This form is a testament to Illinois’s legislative commitment to pollution control and environmental protection. It serves as a detailed reporting tool for the assessment year, requiring comprehensive information about pollution control facilities, including their nature, usage status, and pertinent identification numbers such as the Federal Employer Identification Number (FEIN) and the Illinois Business Tax Number (IBT). Additionally, it delves into the specifics of the pollution control facility, such as its type—be it for air, water, or low-sulfur dioxide emission control—the facility’s Illinois EPA certification details, and the precise location and classification of the pollution control infrastructure. The form further guides the submission process through a step-by-step procedure on completing assessment information, which includes the original and net costs involved, the facility’s operational impacts, and any changes or improvements made. Such meticulous documentation underscores the dual benefits of ensuring that facilities operate within the environmental standards set forth by Illinois law and supporting transparent tax assessment for pollution control facilities. This process not only helps owners keep track of their facility's compliance and financial obligations but also reinforces the importance of responsible environmental practices in the state.