Green Earth Technologies, creator of organic engine products, has released their new automotive lubricant to its G-Oil line, a 10W-30 that has set a new biodegradability standard. The oil biodegraded over 90% in a speedy 9 days, blowing the 28-day rate of decomposition required by the American Society of Testing Materials out of the water. Pretty impressive.
http://www.ecogeek.org/content/view/1818/
http://www.getg.com/index.php