A Voice for Our Ocean

STATEMENT: California Passes Microplastic Pollution Prevention Bill Backed by Ocean Conservancy Scientists

Bill requiring washing machine filters would prevent millions of pounds of microfibers – the most common form of microplastics in environmental samples – from entering California waterways

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© Mel Poole

SACRAMENTO, CA – Today, the California state legislature passed Assembly Bill 1628, which prevents microfiber pollution – the most common microplastics in environmental samples – by requiring that all new washing machines sold into the state by 2029 have microfiber filters that meet a science-based standard for effective filtration. The state Senate passed the bill with a 28-to-8 vote yesterday, and the state Assembly with a 63-15 vote. The bill now heads to Governor Newsom’s desk. Ocean Conservancy joins other co-sponsors, dozens of leading sciences, businesses, and statewide and regional sanitation agency associations in urging the Governor to sign it into law.

“While microfibers may be small, they present a huge threat to the ocean and our health. Once in the environment, they are all but impossible to clean up, which is why this bill is so critical – it will prevent millions of pounds of plastic microfibers from entering the environment each year. California is once again leading the nation in addressing the plastic pollution crisis at the source, this time with microplastic pollution from washing machines. We hope that other states will follow suit,” said Dr. Anja Brandon, Associate Director of U.S. Plastics Policy at Ocean Conservancy.

Each year, it has been estimated that up to 4.85 million pounds of microfibers enter California’s lands and waters each year from washing machines. Microfibers have been found to represent over 90% of all microplastics taken in by marine wildlife in some studies. In animals, ingestion of microfibers has been shown to reduce food consumption, reduce energy for growth, alter gene expression, and block digestive tracts. Bacteria and pathogens can also be found on the surface of microplastics, and when swallowed or inhaled by animals and humans have the potential to spread disease. Microfibers are the most common type of microplastic pollution found in human tissues, as well – microfibers have been uncovered in the human heart, placenta, and other organs.

AB 1628 follows the recommendation made by the California Ocean Protection Council in the Statewide Microplastics Strategy issued in February 2022 by defining the science-based standard for microfiber filtration systems as a system that is embedded in or sold with the washing machine and has a mesh size 100 micrometers or smaller. The bill would require that new washing machines with microfiber filtration systems have a conspicuous label announcing that fact.

These filters have been shown to be a cost-effective solution that can capture up to 90% of microfibers from each load of laundry. Scientists have estimated that installing washing machine filters in just 10% of households can lead to a significant reduction in microfibers at a wastewater treatment plant. Ocean Conservancy scientists estimate that if that study were scaled to the 10.3 million household washing machines in California, it would prevent up to 1.5 quadrillion microfibers from entering wastewater every year, the equivalent weight of over 17 million t-shirts.

Ocean Conservancy, The Nature Conservancy, and 5 Gyres Institute co-sponsored the bill, which is also supported by over 40 environmental groups and nearly three dozen scientists.

Ocean Conservancy plastics pollution experts Dr. Anja Brandon and Dr. Britta Baechler are available for interviews with media about the impact of microfiber pollution and why Ocean Conservancy strongly supported the passage of AB 1628.

About the experts:

Dr. Anja Brandon is the Associate Director of U.S. Plastics Policy at Ocean Conservancy, working to advance policy solutions at the state and federal level to eliminate plastic pollution and support the transition to a circular economy. Dr. Brandon served as one of the principal negotiators for AB 1628. Dr. Brandon was also recently named among Fast Company’s 2023 Most Creative People for her innovate work to help draft and pass the strongest plastics legislation in the country, California’s SB 54. Anja holds a Ph.D. in Environmental Engineering and Science from Stanford University where she was awarded an NSF Graduate Research Fellowship for her work. Her doctoral research focused on understanding plastic waste management challenges and developing novel methods to break down common plastics.

Dr. Britta Baechler is the Associate Director of Ocean Plastics Research for Ocean Conservancy and a scientist who has studied the impacts of microplastic pollution on animals along the Pacific coast testified in support of AB 1628 during a California Assembly hearing this past March. She has more than a decade of experience in fisheries management and marine conservation. In her role as Associate Director for Ocean Plastics Research at Ocean Conservancy, Britta leads primary research on varied topics related to the distribution and impacts of plastic pollution, including prevalence of microplastics in the human food system, movement of trash from inland out to sea and public knowledge and perceptions of the plastic pollution issue.

If you are interested in speaking with Dr. Brandon or Dr. Baechler, please contact Roya Fox at [email protected] or 206-948-7874.

A fact sheet on microfibers can be found HERE.



About Ocean Conservancy

Ocean Conservancy is working to protect the ocean from today’s greatest global challenges. Together with our partners, we create evidence-based solutions for a healthy ocean and the wildlife and communities that depend on it. For more information, visit, or follow us on Facebook, Twitter or Instagram.

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