Resistance to oils and fuels is a property of work shoe soles that ensures the sole material will not be damaged upon contact with hydrocarbons such as oils, gasoline, or diesel fuel. Common materials can swell, soften, lose their slip-resistant properties, or begin to crumble when exposed to such substances, which reduces the safety and durability of the footwear. This property is tested according to European standards, for example, by immersing a sole sample in a test liquid for a specified period of time. For the outsole to meet the standard, its volume must not increase by more than 12% after the test, and there must be no significant hardening or cracking.