HealthyCar.org collects research that measures the presence of key hazardous chemicals in vehicles that can lead to environmental problems. The organization provides a service of searching for the most popular 200 vehicles in the U.S. from 2006 to 2007 model years and rates them on overall vehicle rating and also gives you a chemical rating. Each of their reports comes with a detailed full description.
If you look up your car, you will receive an overall vehicle rating, indicating the level of concern for that auto versus the other vehicles tested. A rating of 0 represents the lowest concern and 5 represents the highest concern.
I did a search for my vehicle and received a 1.6, not too shabby considering the 2006 Toyota Prius received a 1.8.