Denaturing of Ethyl Alcohol: BIS standard denaturants required; additional agents allowed with chief chemist approval and industry justification. Imported ethyl alcohol for industrial use must be denatured and tested before clearance; the Board requires adherence to BIS standards IS 4117-1973 as the baseline list of denaturants, while permitting Commissioners to allow additional denaturants, bitterants or colouring agents to prevent renaturation, subject to Chief Chemist concurrence and demonstration of industry specific need. Assessments may be finalised on merits with verification from State Excise if required, and the Denaturing of Spirit Rules, 1972 apply.