Many hydraulic systems operate outdoors.
In places where hydraulic hoses rupture or seals fail, high concentrations of oil discharge into the environment. This makes the environment subject to potential contamination. Some of the additive normally used in conventional petroleum oil puts water supplies and wildlife, particularly aquatic organisms, at risk. In addition, it takes a long time for petroleum oils to biodegrade. The potential liability, remediation, and operation shutdown costs create the need for environmentally-safe lubricants.