This alkane consisting of six carbon atoms is an the unbranched isomer form of hexane, and is used in numerous applications as an inexpensive and generally non-reactive non-polar solvent that has a higher relative safety and is easily evaporated. This Ultra-Resi, high purity form of hexane is most often used in high-performance liquid chromatography during the mobility phase, but can also be used to extract oil and grease contaminants from water and soil samples for further analysis. Most hexanes are obtained as a byproduct of refining crude oil, and dude to their generally low reactivity they make excellent solvents for reactive compounds. The acute toxicity of n-hexane is extremely low, and inhalation at 5000 ppm for 10 minutes produces vertigo in the exposed, and 12 hours of exposure at 2500-1000 ppm causes drowsiness, fatigue, appetite loss, and distal extremity paresthesia (pins-and-needles burning sensation). The recommended exposure limit in an 8 hour period is roughly 100 ppm.