Compostable mailer certifications: BPI, OK compost and what you can print
A compostable claim on a mailer needs a certification behind it. In the US that usually means BPI certification, which is built on ASTM D6400: the material must break down so that no more than 10 percent of its original dry weight stays on a 2 mm sieve after 12 weeks of industrial composting, and must biodegrade within 180 days. TÜV Austria's OK compost INDUSTRIAL and OK compost HOME are the other marks you will see. Tria's compostable mailer is a 2.5 mil PBAT and corn starch film from 200 units, and the certification documentation for the film comes with the quote, so you print only the marks it actually covers.
This is packaging guidance, not legal advice. Environmental claims are regulated by the FTC and, increasingly, by states. We print the marks your documentation supports and nothing more; the claim itself is yours to sign off.
The three marks, compared
| Mark | Based on | Composting conditions | What it supports on the bag |
|---|---|---|---|
| BPI certified compostable | ASTM D6400 for plastics, D6868 for coated paper, plus BPI's fluorine limits | Commercial and industrial composting facilities | The BPI mark and a qualified "compostable in commercial facilities" claim |
| TÜV Austria OK compost INDUSTRIAL | EN 13432, the European standard | Industrial composting plants | The OK compost INDUSTRIAL mark |
| TÜV Austria OK compost HOME | TÜV Austria's own home composting scheme | Lower temperature backyard compost heaps | The OK compost HOME mark, a backyard composting claim |
The difference between industrial and home is temperature. An industrial composting site runs much hotter and more consistently than a backyard heap, and a film certified only for industrial composting should not go in a garden bin. A mailer that carries only an industrial mark cannot be described as backyard compostable.
What ASTM D6400 actually tests
ASTM D6400 is the US specification for plastics designed to be composted in municipal or industrial facilities. A material has to pass three things:
- Disintegration. After 12 weeks under controlled composting conditions, no more than 10 percent of the original dry weight may remain on a 2 mm sieve. In other words, almost all of it has to fall apart small enough to pass through.
- Biodegradation. The material has to be converted to carbon dioxide, measured against a reference material, within 180 days.
- No harm to the compost. Limits on heavy metals and a plant growth test, so the finished compost is usable.
BPI uses D6400 as its base and adds its own rule on fluorinated chemicals: no intentionally added fluorinated chemicals and a test showing less than 100 ppm total organic fluorine (BPI, fluorinated chemicals).
What the FTC Green Guides let you say
The Green Guides in 16 CFR Part 260 set out how the FTC views environmental claims. The points that matter on a mailer:
- A compostable claim needs competent and reliable scientific evidence that every part of the item, including the seal strip and the ink, breaks down into usable compost in a safe and timely way in an appropriate composting facility or home compost pile (16 CFR 260.7).
- If composting facilities that take the item are not available to a substantial majority of the people where it is sold, the claim must be qualified. "Compostable in commercial facilities, which may not exist in your area" is the usual form.
- An unqualified "biodegradable" claim is risky. The FTC treats it as deceptive unless the item will completely break down within a reasonably short time, which it defines as one year, after customary disposal, and most mailers end up in landfill (16 CFR 260.8). We do not print "biodegradable" on mailers.
State labeling laws
Some states go further than the FTC. Washington, for example, requires products labeled "compostable" to meet ASTM D6400 or D6868, and requires compostable film bags to carry a certification logo and use green, beige or brown coloring or striping with the word compostable at a set size, so shoppers can tell them from ordinary plastic (RCW 70A.455). If you sell into Washington, design the bag around that rule from the start. Other states have their own rules on compostable and recyclable claims, so check every state you ship to.
What Tria's compostable mailer carries
The Tria compostable mailer is a 2.5 mil blend of PBAT and corn starch with a compostable peel and seal strip, printed one or two colors in water-based ink, from 200 units in 10 to 12 business days. The certification documentation for the film, the seal strip and the ink comes with the quote, and it names the marks and claims it supports. A mark goes on the proof only when it matches that documentation. What we will not print is a general phrase like "eco-friendly" with nothing behind it.
Two practical notes. Compostable film has a shelf life of about 12 months from manufacture stored cool and dry, so order what you will use in a year. And it is not recyclable with plastic film, so the bag should say so; we print a short disposal line on the back on request.
| Need | Better choice | Why |
|---|---|---|
| A plastic-free soft mailer for apparel | Compostable mailer | Certified film, under 4 pounds of contents |
| Stock that sits in a warehouse for more than a year | Poly mailer | No shelf life on the film |
| A rigid product or a planned unboxing | Eco kraft mailer box | Paper box that recycles with paper and gives structure |
Sources
- ASTM D6400, labeling of plastics designed to be aerobically composted
- BPI, commercial compostability certification
- BPI, fluorinated chemicals rule
- TÜV Austria, OK compost INDUSTRIAL
- TÜV Austria, OK compost HOME
- 16 CFR Part 260, FTC Green Guides (eCFR)
- Washington RCW 70A.455, compostable product labeling
Rules checked against these sources on October 5, 2026. Regulations change; check the current text before you print.
Questions people ask
What is the difference between BPI and OK compost certification?
BPI is the main US certifier and builds on ASTM D6400, adding a limit on fluorinated chemicals. TÜV Austria's OK compost INDUSTRIAL is based on the European standard EN 13432. Both cover industrial composting. OK compost HOME is a separate TÜV Austria scheme for lower temperature backyard composting.
Can I call my mailer home compostable?
Only if the documentation for the exact film, seal strip and ink covers a home composting certification such as OK compost HOME. A mailer certified only for industrial composting cannot be described as backyard compostable. The documentation that comes with our quote states which claims it supports.
What does the 2 mm sieve test in ASTM D6400 mean?
It is the disintegration test. After 12 weeks under controlled composting conditions, no more than 10 percent of the material's original dry weight may remain on a 2 mm sieve. Separately, the material must biodegrade within 180 days and pass heavy metal and plant growth limits.
Can a compostable mailer go in curbside recycling?
No. Compostable film contaminates plastic film recycling. It belongs in a composting program that accepts it, or in general waste where none exists. We print a short disposal line on the back of the mailer on request.
Can I print biodegradable on the mailer?
We advise against it and do not print it on mailers. The FTC Green Guides treat an unqualified biodegradable claim as deceptive unless the item fully breaks down within one year of customary disposal, and mailers mostly end up in landfill.
Should I choose a compostable mailer or a poly mailer?
Choose the compostable mailer when the brand has a plastic commitment and the stock will be used within about 12 months. Choose the poly mailer when bags will sit in storage for longer or carry heavy loads; it has no shelf life on the film. Both start at 200 units in 10 to 12 business days.