Seattleites, you have been composting wrong.

Seattle Public Utilities says people often put produce bags in the compost bin, but not all of those bags are biodegradable. That messes up the city's composting machines, which are costly to fix.

Sego Jackson at Seattle Public Utilities explains the issue is consumer knowledge.

Jackson: "People are confused about what's compostable and what is not. They are given bags that are tinted green, they used the words eco and bio, they have leaves and trees and symbols on them, and many of the public thinks that this means all bags are compostable, but they are not."

So the City Council plans to establish a color system for produce bags, under a proposed ordinance. Green or brown would be for compostable bags offered at grocery stores. No other takeout bags would be allowed those colors.