Washington: Safeco Stadium (Seattle Mariners)

Seattle, WA

Captain Plastic and Kid CompostCaptain Plastic and Kid CompostBack in 2008, when Safeco Field recycled 12% of their waste, Scott Jenkins, the VP of Ballpark Operations for the Seattle Mariners, thought the upper limits for waste diversion for a stadium was about 50%. By auditing the waste stream, the Mariners discovered that a majority of what was being landfilled could be composted. Switching to compostable service ware virtually eliminated the need to provide landfill containers for fans. The diversion rate for 2012 is 85% and they now have their eyes on achieving a 90% diversion rate.

Products and Brands Composted:
Everything used in food operations is Cedar Grove approved compostable. This includes straws, cups, bowls, hot dog trays, food wraps, forks, spoons and knives. There are only rare exceptions to this.

Collection System: 

Education was a crucial step in facilitating collection. The staff was trained on sorting packaging and back of house prep but the general public needed to know how to sort properly as well. Since the majority of products offered in the Stadium are compostable or recyclable, they have only 16 trash receptacles in the entire park and 600 composting and recycling containers. The trash bins are part of the 12 zero waste stations situated around the stadium to educate guests of the different waste streams at the park. They use compostable bags for food service locations and petroleum bag liners in public areas since they de-bag and inspect before compacting.

Zero Waste SignZero Waste SignSince there is so little trash that comes out of the stadium, the Stadium’s cleaning staff, Aramark, is able to comb through the trash before it’s hauled away for any items that can be recovered for recycling or composting. This, plus the fans generally getting better at sorting their waste every year, has raised recovery levels by 4% from the previous year. Since 61% of their disposed items are compostable, they converted their two trash compactors into compost compactors. There is no need to compact their trash now that it’s easily stored in an open container for hauling. Pick up varies from once a week if the Mariners aren’t playing at home to every game if there’s high attendance.

All the food service ware is labeled “compostable” to make it easier for patrons to identify compostable items from recyclable ones, however that isn’t always enough. Because trash cans are not easily available, patrons quickly see that products are meant to go in the composting bin and do not deliberate on finding the trash can. To further educate fans, the Stadium broadcasts videos on what can be sorted into what bins on the jumbo screens and play games to bring more attention to composting. For instance, they give away bags of compost four times a year to show how the composting loop comes back to the stadium.

In 2012, they started a series of Sustainable Saturdays sponsored by the chemical company, BASF. For the Saturday on Earth Day Weekend, the first 10,000 fans to arrive to the Stadium received a free kitchen compost starter kit courtesy of BASF, EcoSafe, and Seattle Public Utilities. During each Sustainable Saturday, they hold the Kid Compost Trivia to test the fans’ knowledge on sustainability. After the first inning of the game, trivia questions are broadcast on the centerfield video board and fans text in their answers. Winners are awarded a Kindle Fire and signed baseball by Kid Compost, the eco-mascot of the Mariners, at the end of the 7nth inning. The main purpose of the games and extra education is to bring zero waste practices back to the fans’ homes.

Compost Process: 

Safeco Field Soil GiveawaySafeco Field Soil GiveawayThe compostable materials are collected by Cedar Grove Composting and hauled to their local facility in Seattle, WA. They use a GORE™ Cover In-Vessel System to process the organics they receive. It typically takes 60 days to actively compost and 60 days to cure the compost pile in which all compostable food service ware is undetectable. They only allow food service ware that they have already tested and approved with their system to make the compost process run smoother. Check out our report on Cedar Grove here.

The loads brought to Cedar Grove from Safeco Stadium have a low 5% contamination. This contamination rate is mostly due to petroleum cutlery and condiment packets that have made their way into the compost bins. These are screened out by Cedar Grove.

Safeco Stadium uses the finished compost on their grounds and fields to complete the loop of composting. About four times a year, Safeco Field Soil from Cedar Grove is given to lucky winners attending baseball games to show game-goers how the compostables they put in the compost bin gets processed and used right on the field again and that compost is good for their home flower and vegetable beds as well.

Size of Operation: 

The stadium is 1.1 million square feet large and can seat 47,000 guests. From November 2011 to October 2012, 1.6 million people came through the stadium. In that one year, 985 tons of material was generated, of which 598 tons or 61% was composted. The overall diversion rate for the year was an impressive 85% and is expected to grow in coming years.

Dollars and Sense: 

In 2012, the cost to haul to a landfill (includes hauling fees, tonnage, trip fee, and account fee): $221.70/ton
In 2012, the cost to haul to a compost/recycling facility (includes hauling, tonnage, trip fee, recycling credits): $92.17/ton
In 2012, the cost to haul compost only: $134.70/ton

Typically, compostable ware is more expensive than most of its petroleum counterparts. But now that there is more demand for compostable ware due to Seattle’s polystyrene bans, the cost is steadily coming down. To see the cost savings from switching to compostables you have to look at the big picture. You have to see that hauling costs are less for recycling and composting in the Seattle area. Also, there is money made from recycling, especially from scrap metal and aluminum, which make recovering materials more attractive. But to look at the finer image, some compostable products are cheaper than their petroleum counterparts, such as the hard plastic dinner plates they used to carry. An interesting cost saver was asking diners if they wanted a condiment with their meal rather than handing out the single packet choices without asking which they would like with their meal. Asking first has saved about 50 cents per plate since nothing was wasted.

Altogether, from November 2011 to October 2012, they saved about $100,000 because they compost and have converted most of their stream to cheaper hauling.


One challenge they faced was the thermal properties of cutlery. The forks and spoons did not fare well when they came in contact with hot potatoes or soups. They are currently using petroleum based cutlery as they wait for a heat-resistant and Cedar Grove Approved option to be made available. What some patrons could do to overcome the soup issue is to not have the spoon sitting in the soup between sips.

Tips for Replication: 

1) If everything you serve is either compostable or recyclable, avoid having a trash bin present. Seeing three bins confuses guests and leads them to use the default of putting everything in the trash since it’s easier for them. By having significantly fewer trash bins and more composting and recycling bins forces people to think about what bin to put their items in.

BASF Compostable Peanut BagBASF Compostable Peanut Bag2) Learn from the people taking the journey with you or ahead of you. This whole journey takes time and effort and the best way to get ahead is to take one step at a time. You need to properly train staff, get the right champions, and promote and educate to get the system in place. Calculate your baseline when you make the initial switch to keep track of your progress. Make course corrections as you face challenges. As you succeed, you and your staff will be more motivated to do even better.


Scott Jenkins
Vice President Ballpark Operations
1250 1st Avenue South
Seattle, Washington 98134
(206) 346-4001