Lower purity hexanes in bulk are used in the formulation of adhesives for shoes, leather products, and roofing materials. They are also integral to the extraction of cooking oils from seeds such as canola and soy oil, and their common use in soybean oil extraction in the US is a subject of controversy due to the high toxicity of hexane exposure when ingested or inhaled. As a rule, hexanes are all colorless, and their boiling point varies little by the isomer type. Branched hexane isomers generally have lower boiling points than n-hexane, however their melting points can vary by as much as 100 degrees Fahrenheit. Hexanes also possess remarkable vapor pressure even at room temperature. Proper safety protocols limiting exposure must be observed when workers are exposed to hexanes over extended time periods in higher concentrations. There have been several documented incidents of occupational hexane poisoning in Asia and Europe in both commercial and industrial manufacturing settings in the past decade.