Compostable vs. Biodegradable
While “biodegradable” and “compostable” may appear to be synonymous terms, there are important differences.  From geometry we know that while every square is a rectangle, not every rectangle is a square.  That’s a lot like the difference between the terms “biodegradable” and “compostable”.  While everything that is compostable is biodegradable, not everything that is biodegradable is compostable.

“Biodegradable” only means that it will decompose by bacteria or other living organisms.  There are no specifications on environments or timeframes for this decomposition.  Technically speaking, many things are biodegradable, but the rate and success of decomposition depend on the specific environment and access to active bacteria or other organisms to break it down.

“Compostable”refers to a specific timeframe and environment that is validated by a set of standards from organizations like ASTM.  These standards are designed to provide scientific verification that a material can safely break down in a commercial compost facility and will not negatively impact compost quality.

In this way, “biodegradable” is not an appropriate attribute for describing the end of life for products and packaging because it lacks specificity on timeframe and environment.  This term is generic and misleading, which is why it is illegal to market products as “biodegradable” in 4 states.

Common Materials and Finished Products
BPI-certified products cover a wide range of materials but can be roughly organized into a few categories.  Rigid, resin-based items are products like clear cold cups, clear containers, and cutlery that are made predominantly from different bioplastic resins.  Fiber-based items like plates, bowls, and containers are typically made from fibers like bagasse, wheat straw, or other molded pulp.  Coated paper items like hot cups and soup cups utilize paperboard with bioplastic coatings.  Film-based items like compostable liners and flexible snack packaging combine bioplastic resins with other technologies.  BPI’s searchable database of certified products offers a complete list of BPI-certified materials and items.

Need for BPI Certification
BPI’s third-party certification program distinguishes products that meet ASTM standards (and BPI’s other requirements) from those that do not.  When looking at a product that is self-declared to be compliant by the manufacturer or brand, a consumer or composter will not know what standards have been met for the product.  The third-party certification process ensures that correct components are used and that the correct tests have been conducted to ensure safety for the environment.  Imagine seeing “organic” written on a food product but not seeing the USDA Organic mark.  The USDA Organic mark tells the consumer that a third-party has confirmed the claim.  The BPI Certification Mark serves the same purpose for industrially compostable products in North America.  Additionally, Washington State requires third-party certification for products making “compostable” claims.  Other states are expected to follow Washington’s lead on labeling requirements like this one.

Importance of Labeling Compostable Products
The BPI Certification Mark indicates the end-of-life opportunity for a compostable product.  BPI Certification guides manufacturers in designing items, understanding what ingredients they can use, and how to make an independent compostability claim that consumers and composters can trust.  The BPI Certification Mark helps consumers to identify and trust that an item is compostable and can be diverted with food scraps where programs exist.  Composters are able to identify and trust that certified products mixed with food scraps and yard trimmings will break down during the regular composting process and will not negatively impact compost quality.  Considerations and recommendations for thoughtful labeling are contained in BPI’s “Guidelines for the Labeling and Identification of Compostable Products and Packaging”.