Crude oil is an essential commodity used in the refinement of gasoline. The majority of gasoline is derived from petroleum naphtha, an intermediate hydrocarbon liquid. Petroleum naphtha has low octane ratings that must be desulfurized and then catalytically reformed to produce high-octane gasoline. To do so, petroleum naphthas are typically broken down using toluene, an aromatic hydrocarbon that is widely used as industrial feedstock or solvent which is capable of dissolving paints, thinners and sealants. In gasoline, toluene dissolves the sulfur, thus raising the octane to appropriate levels for use in combustible engines. In this chemical plant, toluene is produced and contained in a bulk tank for later use in petroleum refining processes. Toluene is a highly volatile liquid that requires instruments with hazardous certification. The intrinsically safe EchoTouch ultrasonic level transmitter was chosen for this application, and combined with an intrinsically safe DataLoop level indicator for hazardous level measurement and indication.