CBP does not conduct EPA pre-clearance for incinerators at the port of entry, but the equipment must comply with EPA New Source Performance Standards (NSPS) and National Emission Standards for Hazardous Air Pollutants (NESHAP) before it can be legally operated in the United States. Importers and end-users are responsible for ensuring the unit meets applicable emission standards; non-compliant equipment cannot be lawfully put into service regardless of whether it cleared customs.

A rotary kiln used for cement clinker production processes calcium carbonate and other mineral inputs, not ores or metals, so it does not fall under the metal-treatment furnace heading (74136). It would instead be classified here as a nonelectric industrial furnace not elsewhere specified. The material being processed—mineral versus metallic ore—is the primary classification criterion, and manufacturer documentation specifying the kiln's design application is the key supporting evidence.