Two days ago the Boston City Council voted to ban single-use plastic bags in stores, restaurants, and pharmacies, and charge at least a 5 cent fee for reusable, paper, or compostable bags. This joins a wave of legislation enacted or proposed around the country in the last 10 years banning single-use plastic bags. This should make a small dent, locally, in reducing plastic in the waste stream and in the environment. However, the allowed exception to the ban, "compostable plastic bags", should be removed. We do not want compostable plastic bags either.
The underlying problem is not just single-use plastic bags, but rather, all thin film plastic packaging. Each year more and more consumer products are sold with thin film plastic to protect and preserve the product. Bread is sold in bags, cereal boxes contain plastic liners, dry-cleaning is sent home in bags, newspapers are delivered in plastic sleeves, inflated bags are used as shipping pillows inside boxes. Single use grocery bags make up less than 40% of the plastic bags that a typical consumer takes home. The real problem is that all bags are difficult to recycle, and this is where "compostable" bags become a problem.
It is highly unlikely that we will be able to ban the use of all thin film plastic packaging, so we are going to need to find a way to reduce/reuse/ and recycle it. While compostable bags sound environmentally smart, the fact is that they contaminate the recycling stream for all other thin film plastic. Compostable plastic bags look and feel just like other plastic bags, and people combine them together when they recycle, and they become impossible to remove. No human sorter can work cheaply enough and no machine has been invented yet (and it has been tried) to remove this type of contaminant from the plastic bag recycle stream. Compostable bags break down when exposed to water, air, and light, and this is not a property that recycled plastic buyers are looking for.
The proposed law, with it's allowed exception for compostable bags, should be revised. Please remove compostable bags from the legislation, they are bad for the recycle stream which makes them bad for the environment.