Tens of thousands of people will converge on the city in October to watch or participate in the Baltimore Running Festival. But if all goes according to plan, they won't leave much of a footprint.

Organizers of the marathon and the day's other races will recycle cups, hand out reduced-plastic bottles, compost food and waste, collect discarded shoes, and use alternative-energy cars. They'll hand out race shirts made from 100 percent recycled materials. And they'll plant 100 trees along the race course.

Like other areas of modern life, large sporting events are being influenced by higher public expectations, stronger municipal pressure, and organizer and sponsor enlightenment. This year, organizers in Baltimore and around the nation have stepped up efforts to get runners to stop trashing the road to the finish line.

That's an ambitious goal for such races - in Baltimore alone, supplies for runners include 400,000 cups of water, 19,000 bananas and 6,000 apples.

Lee Corrigan, president of Corrigan Sports Enterprises, the event organizer, said the sustainability goals have required a lot of extra work. There was research into what is recyclable and how to get participants information without making more waste. And 125 more volunteers were recruited to make sure trash, recycling and peels all go in the right cans. There is also a yet-to-be-determined extra cost to offsetting the carbon emissions from 20,000 runners through NativeEnergy, which builds renewable energy projects on Native American land and family farms.

But it's worth the investment, he said. The marathon and other festival races will attract more eco-minded runners in the future and more sponsors that Corrigan needs to put on such a large-scale event.

"The whole running community is headed this way," he said. "And we're on top of the wave."

Baltimore's title sponsor, Under Armour Inc., came up with new features to add this year through in-house discussion and some examination of other events, said Will Phillips, manager of environmental strategy. The biggest is the event shirts, which are made from recycled material and come from the company's new Catalyst line. Considering the record size of this year's event, he said, the move to sustainability is "very timely and important."

Other sponsors are also making changes, including Aquafina, which is supplying about 30,000 water bottles made with 50 percent less plastic. The company will take the lead in collecting them. They will also collect shrink wrap, wood pallets and cardboard, which make up the bulk of the finish line trash.

Ed Hinde, a consultant for Healthy Living Promotion, a firm helping Aquafina and the marathon with the sustainability program, said such efforts are still new around the country. But as the message spreads, he expects participation to increase. And that soon many cities will demand at least recycling. "In many cities, if it's not mandated yet, it will be," he said. "But then there are public expectations. The runners want this."

Baltimore did not have requirements, but did have input and will help haul away trash and recyclables. Valentina Ukwuoma, who heads the city's Bureau of Solid Waste, said officials are beginning to reach out to event organizers who do not contact them first. She said the marathon will be the second-largest city event where recycling is offered (after Artscape), and will serve as a model for future events.

Many races, including Baltimore's, are also seeking official certification as "green" from a new national group that has set standards for endurance sporting events. Certification means a third party has ensured sponsors and participants the events are making responsible changes, said Marisa McGilliard, executive director of the Council of Responsible Sport or ReSport, launched in 2007 with a series of nine races. On the list this year are 17 races that have or seek certification.

Race organizers across the nation have been innovative in the green elements they've added, such as using recycled bicycle parts to make medals handed out at the finish line or buying all their food locally. Reducing waste and offsetting carbon emissions from participants have been the most common, said Kristen Gunderson, director of certification. And nearly all the races have eliminated paper registration.

For each step, organizers are awarded points toward certification - the same way the far more established U.S. Green Building Council awards certification for environmental construction.

"These events are trying to shift the meter to be more accountable," McGilliard said. "There was no one to provide objectivity on what it is to go green or be a sustainable event. We're trying to bring that."

Marathons in Portland, Ore., and Hartford, Conn., already are established leaders, said Lisa Neirotti, director of the Sports Management Program in George Washington University's School of Business.

After 15 years of environmental consulting for the U.S. Olympic Committee, Neirotti developed a score card for large sporting events to assess their level of environmentalism and she offers information on what's a good or bad investment in time or money. The National Football League and several professional and youth sports teams, as well as road races, began using it this year.

Many races had taken small steps, she said, but the real push began in 2008 when race managers held a sustainability conference. Baltimore organizers attended.

"All of a sudden they looked around and said, 'We create a lot of trash,' " she said.

Best practices are still evolving, even among those certifying races, and some organizers still need to determine what works in their area, Neirotti said. They need to know, for example, what plastic cups are recyclable and what public transportation and green hotels are available.

"There are so many road races now, that's the importance," she said. "If everyone did something, it would make a big difference."

Supplies for the race
Some of the supplies that go into the Baltimore Running Festival:

•400,000 cups

•16,687 gallons of water

•2,400 five-gallon jugs out on the course

•17 water stops

•19,000 bananas

•6,000 apples

•5,000 oranges

•1,000 volunteers, including 125 dedicated to recycling