Last year, Portland-area hospitals received a $250,000 grant from the EPA through the Oregon Clean Diesel Initiative (PDF) to establish a “clean diesel” zone (PDF), around all of its hospitals, Oregon Live reports. So far the grant has been used to ensure clean diesel emissions from vehicles in the hospitals’ own fleets.

But when Portland’s Andersen Construction began work on Portland hospital’s $42 million expansion, it decided to experiment with ways to eliminate all diesel exhaust from the job site when it began receiving complaints from the hospital about smoke.

It was so successful, that Providence plans to extend the clean diesel zone to cover emissions from vendor-owned vehicles on all its campuses as well.

“It will end up being part of the contract language for companies doing business on our campuses,” said Mike Geller, who is overseeing the Providence Health System clean diesel initiative. “We will be putting in language giving preferential treatment to vehicles using ultra-low or biodiesel or retrofits.”

Many other contractors in the Portland area have begun to use biodiesel and ultra-low sulfur diesel in their heavy equipment.

Portland’s Walsh Construction, for example, uses B20 in delivery trucks. Stacy and Witbeck plans to use B20 for all of its heavy equipment including haul trucks, boom trucks, excavators, loaders and dozers when it builds a light rail line next year on downtown Portland’s Transit Mall.