{"id":1045157,"date":"2026-09-05T15:31:16","date_gmt":"2026-09-05T15:31:16","guid":{"rendered":"https:\/\/www.europesays.com\/us\/1045157\/"},"modified":"2026-09-05T15:31:16","modified_gmt":"2026-09-05T15:31:16","slug":"are-compostable-green-bags-ok-to-use-in-san-francisco","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/us\/1045157\/","title":{"rendered":"Are compostable green bags OK to use in San Francisco?"},"content":{"rendered":"<\/p>\n

Using a green compostable bag to line your compost pail is incredibly convenient.\u00a0<\/p>\n

Oakland\u2019s composting service doesn\u2019t accept the bags<\/a>; Alameda County calls them \u201ccontaminants.\u201d<\/p>\n

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In San Francisco, Recology accepts the bags, but there\u2019s a catch: They generally get picked out, by machine or by hand.<\/p>\n

The reason: They gum up sorting machines, and are also hard to distinguish from regular plastic bags.<\/p>\n

\"Compost<\/p>\n

Green compost bags hang from an excavator bucket during composting intake at Recology Blossom Valley Organics in Vernalis (San Joaquin County) on Aug. 31. The bags can gum up sorting screens.<\/p>\n

Noah Berger\/For the S.F. Chronicle<\/p>\n

Here\u2019s what happens in San Francisco:\u00a0<\/p>\n

Trucks from Recology\u00a0\u2014 which handles the city\u2019s bins\u00a0\u2014 haul compost to the San\u00a0Francisco Transfer Station & Hazardous Waste Facility. There, the contents are fed into a large cylinder with four-inch holes that filters out big materials\u00a0\u2014 the first of a series of screenings. Some compostable bags plug up the screens, and others get screened out.\u00a0<\/p>\n

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Further screening occurs at Recology\u2019s facility in San Joaquin County, where the compost gets left in heaps to biodegrade. Here, workers also pick out anything that looks like plastic, both manually and with screens.\u00a0<\/p>\n

That includes composting bags, unless they\u2019ve broken open and are in small enough pieces to make it through the screens.<\/p>\n

They\u2019re a \u201cchallenging material\u201d to work with, Recology spokesperson Robert Reed said by email.\u00a0<\/p>\n

\"Excavators<\/p>\n

Excavators move compost at Recology Blossom Valley Organics.<\/p>\n

Noah Berger\/For the S.F. Chronicle<\/p>\n

The \u2018messy middle\u2019<\/p>\n

But people like the bags. They are stronger and less leaky than other options like paper liners. Nonetheless, in addition to the physical challenges in the screening process, there are questions over whether the green compostable bags\u00a0\u2014 generally known as bioplastics\u00a0\u2014 add real value to the compost, which Recology sends primarily to local farms, or leave microplastic residue.<\/p>\n

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Research appears to be scant on the impacts of bioplastics on compost, soil quality and plant growth\u00a0\u2014 and the National Organic Program said that it was unclear what benefits compostable bags could provide to compost.<\/p>\n

From San Francisco\u2019s perspective, the ultimate goal of composting outweighs the inconvenience of pulling them out. The city doesn\u2019t want to risk confusing people, and turning them off of composting, according to Hilary Near, commercial Zero Waste senior coordinator for the San Francisco Environment Department.\u00a0<\/p>\n

\u201cIt\u2019s a messy middle,\u201d said Near.<\/p>\n

Compostable bags are made of plant-based biopolymers, and they can also contain products and additives that allow them to resemble synthetic plastic, according to a National Organic Program technical report<\/a>.\u00a0<\/p>\n

According to the Biodegradable Products Institute, a prominent certifier for\u00a0compostable products in North America, products that it certifies must meet a minimum benchmark of being at least 90% degradable in an industrial facility.<\/p>\n

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However, the designation does not require that they leave no microplastics behind.\u00a0<\/p>\n

While Near said she didn\u2019t discount the issue of compostable bags leading to microplastics in compost, she doesn\u2019t see these microplastics as nearly as big a problem as the issue of distinguishing microplastics from regular plastic bags.<\/p>\n

Starting next June, people in San Francisco and indeed all of California will not be able to buy compostable bioplastic bags anyway: Assembly Bill 1201 will require that bags with those labels meet federal standards set by the USDA for what goes into compost, and certified\u00a0compostable products\u00a0\u2014 whether they be bags or cups\u00a0\u2014 don\u2019t meet that standard.\u00a0<\/p>\n

What\u2019s even more confusing for consumers is that \u201cbiodegradable\u201d does not have a standard associated with it, whereas \u201ccompostable\u201d does, Near said.<\/p>\n

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\"An<\/p>\n

An excavator takes in a shipment of material to be composted at Recology Blossom Valley Organics in Vernalis.<\/p>\n

Noah Berger\/For the S.F. Chronicle<\/p>\n

If you want to keep using the green bioplastic bags, go for one labeled as \u201ccompostable.\u201d State law requires that any product labeled with the word \u201ccompostable\u201d meet a certain set of standards, as certified by BPI or other groups. (These particular standards apply only to industrial compost facilities\u00a0\u2014 so if you\u2019re looking to put the green bag in your home compost, don\u2019t, since it won\u2019t break down unless it\u2019s treated under high temperatures at an industrial scale.)<\/p>\n

The Biodegradable Products\u00a0Institute said that its certification \u201cevaluates the ingredients and finished product to ensure the material breaks down completely and does not persist.\u201d The group says that \u201cconventional plastic is the real contamination issue, and unfortunately there is a lot of it because California does not have strong labeling requirements to identify certified compostable products easily.\u201d\u00a0<\/p>\n

Recology specifically notes that BPI-labeled bags are allowed in compost, and it prohibits those just labeled as \u201cbiodegradable.\u201d Even so, the compostable bags are still likely to get plucked out.\u00a0<\/p>\n

\"Non-compostable<\/p>\n

Non-compostable materials fall from a conveyor at Recology\u2019s facility in the San\u00a0Joaquin Valley.\u00a0<\/p>\n

Noah Berger\/For the S.F. Chronicle<\/p>\n

Alternative options<\/p>\n

So for the avid composter looking to ease up the system, what can you do?\u00a0<\/p>\n

According to Will Brinton, a soil scientist who has studied compostable bags for decades, the thickness of the bioplastic bags is an important factor. Choosing thinner bags could get them through the composting process more easily.\u00a0<\/p>\n

Reed, the Recology spokesperson, said he puts a\u00a0paper towel at the bottom of his compost pail to control odor. Then he puts in scraps \u2014 banana peels, eggshells, etc. Each night, he empties the pail and rinses it.\u00a0<\/p>\n

\u201cDo that and you will wake up to a fresh kitchen every morning. No bag required. And more economical,\u201d Reed said by email.<\/p>\n

Another choice, Brinton said, is organic materials \u2014 use\u00a0paper liners or bags that will deteriorate much faster.\u00a0<\/p>\n

\"Recology<\/p>\n

Recology spokesman Robert Reed examines finished compost at Recology\u2019s Blossom Valley Organics facility in\u00a0Vernalis on Aug. 31. Reed said he lines his compost pail with a paper towel and empties it and rinses the pail each night.<\/p>\n

Noah Berger\/For the S.F. Chronicle<\/p>\n

(Experts note that for paper, just avoid<\/a> anything that may have silicone in it, like many types of parchment paper.)<\/p>\n

Brinton acknowledges that it\u2019s going to be messier than a\u00a0bioplastic. It\u2019s clumsy, and may soak through.\u00a0\u00a0<\/p>\n

But for this, \u201cmessy is good,\u201d Brinton said.\u00a0<\/p>\n

Kate Galbraith (kgalbraith@sfchronicle.com) contributed to this report.<\/p>\n","protected":false},"excerpt":{"rendered":"Using a green compostable bag to line your compost pail is incredibly convenient.\u00a0 Oakland\u2019s composting service doesn\u2019t accept…\n","protected":false},"author":3,"featured_media":1045158,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_share_on_mastodon":"0"},"categories":[23],"tags":[15173,746,2750,159,67,132,68],"class_list":["post-1045157","post","type-post","status-publish","format-standard","has-post-thumbnail","category-environment","tag-bay-area","tag-environment","tag-san-francisco","tag-science","tag-united-states","tag-unitedstates","tag-us"],"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@us\/117219156700926275","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/1045157","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/comments?post=1045157"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/1045157\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media\/1045158"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media?parent=1045157"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/categories?post=1045157"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/tags?post=1045157"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}