Oklahoma has made changes to sales and use tax rules affecting manufacturers. An amended rule states that a contractor or a subcontractor can purchase tangible personal property or services exempt from sales and use tax pursuant to a contract with a manufacturer for the construction and improvement of manufacturing goods, wares, merchandise, property, machinery and equipment for use in a manufacturing operation classified under North American Industry Classification System Code 324110 (Petroleum Refineries). A rule on vendor responsibilities in sales to manufacturers is amended to state that when sales are made to purchasers claiming an exemption pursuant to a contract with a manufacturer as described above, the vendor must obtain a copy of the exemption letter or the manufacturer’s sales tax exemption card as well as documentation indicating the contract between the contractor and manufacturer. Additionally, the vendor must obtain the purchaser’s certification on the front of the invoice or sales receipt stating the name of the exempt entity, that the purchases are being made on behalf of the entity, and that the purchases are needed for the completion of the contract. (Rules 710:65-1-7, 710:65-7-9, 710:65-7-13, 710:65-13-152.1, 710:65-19-55, 710:65-19-56, 710:65-19-76, and 710:65-19-210, Oklahoma Tax Commission, effective May 11, 2012)