Some contractors might already be using it. Minnesota mandated it's use last year. The following is some good background information on biodiesel.

http://www.federalsustainabili.....ntents.htm

I guess this will be my assignment for the week. I received an e-mail from somebody who is running a Caterpillar 3406E engine with 50%Hysee Biodiesel and 50% straight diesel.
I have also worked on projects where they replaced the hydraulic fluid with vegetable oil. That way if you spring a leak the site doesn't become a Superfund,