Used oil is such a resource.
0f the approximately 1 billion litres of lubricating oils that are sold in Canada each year, about one half can be recovered for reuse. However, currently only 200 million litres are actually being recovered. The balance is lost during use or disposed of in environmentally inappropriate ways. Used oils may contain small quantities of hazardous substances that can threaten air, soil and groundwater quality in areas where careless disposal prevails. Used oil can be defined as oil that has picked up foreign substances, or contaminants.