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Case Study: A Look at Contamination Reduction in the State of Washington

A partnership that combined city, county, haulers, and their material recovery facility (MRF) to show the effectiveness of messaging at the curb in Spokane with amplified messaging throughout Spokane County.

As with many recycling education programs, reducing contamination was the primary goal for a city-county collaborative project that took place in the state of Washington in the City of Spokane and Spokane County.

With the contamination goal at the forefront, this grant, funded as part of the West Coast Contamination Initiative would not have been possible without The Recycling Partnership’s 2019 West Coast Contamination Initiative Research Report. The initiative was funded through an initial $1 million investment paying dividends on a regular basis with a goal to increase the quality of recyclables collected curbside in California, Oregon, and Washington.

We know recycling behavior change, infrastructure improvements, and equitable collections do not happen overnight. It takes time and efforts of many to create this change. Working along the west coast, The Recycling Partnership has been collaborating with state and municipal leadership to develop tactics, best practices, and tools made available to communities from San Diego to Seattle, and Spokane as showcased in this case study, to recycle more and better.

“By the end of this grant opportunity, we had many key elements that made for great results,” says Asami Tanimoto, Senior Community Program Manager at The Recycling Partnership. “A partnership that combined city, county, their haulers, and their material recovery facility (MRF) involvement and results that show the effectiveness of messaging at the curb with amplified messaging throughout the county.”

Both the city and county focused on decreasing contamination, and each used similar messaging to educate residents and focus on a common contaminant – plastic bags. Between June – September 2020, the campaign was implemented, and measurements were recorded throughout to determine the program’s effect on contamination.

Education at the Curb and in the Mail

In both the city and the county, the first step in education was an information card. Being such a large geographic area of recipients, the cards were customized for each jurisdiction’s accepted materials list but overall, had the same look and feel.

Additionally, and specifically in the city, Spokane conducted a cart-tagging recycling education campaign. It provided a comprehensive education and outreach strategy that involves a team of recycling inspectors who visited over 30% of Spokane’s single family household’s recycling cart and provided feedback on how to improve items that make it into the cart. Carts with contaminated items in them were tagged highlighting the item that didn’t belong. This process was repeated through four collection cycles and data collected each time about if the cart was tagged for a contaminant or not.

The county and their haulers decided on a cart tag tied to their recycling cart included information about what is recyclable on one side with the other side focused on not putting plastic bags in the cart. About 13,000 single-family households received this tag, over 40% of the County’s single-family residents that receive curbside service.

As with any successful recycling education campaign, it is not only about what is sent to mailboxes or tagged on a cart. The Recycling Partnership research shows residents need to see a message seven to 10 times for it to sink in. So along with the postcards and tags, both the city and county also utilized local media to share information, posted to social media, created videos, and did blog posts, plus the city also sent information to residents with a city bill that went out during the same timeframe.

This city and county education is another example of how a community can use many communications outlets and channels to reach their residents in the most convenient time and place for the message to matter. For effective behavior change to occur, messaging where the behavior happens is crucial.

Primary Contaminant Continues to be Plastic Bags

The city and county knew that plastic bags were consistently a problem at the local material recovery facility (MRF). And those can be either plastic bags on their own like the ones from grocery stores, or residents bagging their recyclables and placing the full bag into their cart. Both of which, should not be in recycling carts. So, both the city and county focused on plastic bags as their top issue in communications to residents.

Picking a common top issue is a great way to harmonize recycling messaging throughout a region, even when there are different accepted material lists or ways to communicate with residents.

With the city’s implementation of the cart-tagging recycling education program, they were able to gather insight into the effectiveness of tagging carts for contaminants. As mentioned before, the process is repeated through four collection cycles and during each cycle, data was collected. The city saw a reduction in carts tagged for bagged recyclables decrease by 50% by week 4, and a 21% reduction in carts that had loose plastic bags in them.

Education Works, Even Long-Term

Before the initial education occurred in the city and county, an inbound MRF audit was conducted to develop a baseline for contamination. After the summer of 2020 education project, contamination in the carts decreased by 46%.

Taking it one step further, the county asked the local materials recovery facility to audit some of the routes after 7-10 months. They wondered is the contamination rate continued to stay down. The audit showed that contamination had increased slightly but not significantly to the level where it was prior to the cart tagging campaign.

So even seven to 10 months after the initial cart tagging, the beneficial effects of lower contamination rates were still being recognized. Reduced contamination means cleaner and better recyclable materials. And the County had information showing that periodic education would continue to be necessary to keep contamination down.


The work done in the City of Spokane and Spokane County is a prime example of how a city and county can work together to reduce contamination and improve its overall recycling system. Each had similar messaging, and each saw a reduction in contamination right away, that continued to be recognized even seven to 10 months later.

You can learn more about how to fight contamination in your community in The Recycling Partnership’s Anti-Contamination Toolkits, for curbside and drop-off programs.