HB 1670 -- SALES TAX EXEMPTION FOR POLLUTION CONTROLS This bill removes the required certification by the Director of the Department of Natural Resources before a sales and use tax exemption applies to the purchase or lease of machinery, equipment, appliances, and devices used solely to prevent, abate, or monitor water or air pollution and any materials and supplies used in the installation, construction, or reconstruction of the machinery, equipment, appliances, and devices.Copyright (c) Missouri House of Representatives