Environmentally preferred lubricants fulfill a niche in the total lubricant marketplace; however, there is not a universally accepted definition. The industry generally identifies them by three parameters:

Type	Renewable/Reusable Base Stock	Degree of Toxicity	Degree of Biodegradability
Petroleum	NO (Virgin Group II)	Moderate-High	LOW
Re-refined Petroleum	YES (Resuable Group II Base Stock)	Moderate	LOW
Synthetic	NO (Group III)	Slight-Moderate	MEDIUM**
Bio-based	Yes (Renewable Group V Base Stock)	Insignificant	HIGH