Tuesday, October 12, 2010

The Promise and Problems of Corn Plastic

Those of you who follow us know that we’ve been on an anti-petroleum-based-plastic crusade of sorts.

Because we’re trying to change an industry notorious for pimping tons of plastic swag that ends up languishing in landfills, we tend encourage the use of biodegradable alternatives to petroleum-based plastic materials whenever possible. We also advocate eliminating plastic use altogether when it’s not really needed.

We‘ve sourced a fairly wide selection of promotional product alternatives made in the USA from a promising biodegradable polymer called PLA, better known as corn plastic. PLA can also be made from other renewable plants, including soy, peanuts, and potatoes.

PLA is an alternative to plastic polyethylene terephthalate (PET), the petroleum-based material used in many consumer goods and product packages.

You may have seen PLA packaging recently at Whole Foods, Wal-Mart, Target and Wild Oats Stores. The material was used to package the DVD of Al Gore’s film, An Inconvenient Truth. And from pens and heavy-duty coffee mugs (see photo above) to trade show badges, you can now put your logo on many practical corn plastic goods that might otherwise be made of conventional plastic.

Innovation is seldom without controversy. And there is a serious controversy in sustainability circles about whether or not corn-based plastic is really better for the environment. We recently attended an Eco Tuesday function in San Francisco, where several of us lingered after the event to carry on a spirited discussion about the pros and cons of corn-based plastics.

What follows are some points made on both sides of that discussion, and also our nuanced take on the issue:


• PLA biodegrades into harmless natural compounds in the right conditions. It is made in the USA from a renewable resource and can be composted into fertilizer. (On the flip side: conventional plastic is made from oil, contains toxins, and takes between 100 to 1000 years to break down.)

• PLA is recyclable as well as biodegradable – if you have the right facilities to do those things.

• PLA is part of a broader solution to keep petrol-plastic out of our environment and could take pressure off our bulging landfills and our environment (plastics already take up 25 percent of dumps by volume, and scientists recently reported a toxic vortex of plastic debris twice the size of Texas swirling around the Pacific Ocean).

• Producing PLA uses 65 percent less energy than producing regular plastics, according to independent analysis (funded by its maker). It also generates 68 percent fewer greenhouse gases, and contains no toxins.

• PLA is an affordable alternative to conventional plastic, so it’s reasonable for industry to adopt it.


• Yes, it’s fully biodegradable within a few months, but you can’t just throw it in your backyard’s compost pile. To decompose, PLA requires a temperature of close to 200 degrees and a special type of composting facility.

• There are currently few facilities nationwide that accept PLA, and most municipalities don’t now have the capacity to sort it or accept it for compost or recycling. As such, under current systems, most PLA could end up in landfills, where it may not break down any faster or more thoroughly than other forms of plastic

• Corn is proving to be a less-than-ideal solution for fuels (Google: "corn ethanol problems") and some question its use for products and packaging at a time of growing global food shortages.

• Corn production is relatively energy and water intensive, uses pesticides and fertilizers to grow, and some genetically modified corn has reportedly been used in PLA. Corn production is also heavily subsidized by the U.S. government.

• Corn plastic products aren’t stable at high temperature, so it isn’t a good plastic alternative in all applications. PLA tends to melt at temperatures above 115 degrees. So your lightweight compostable corn plastic soda cup could morph into a pancake if you leave it in your car on a hot day.


We acknowledge that there are many legitimate concerns with corn plastic, but we believe it should be further adopted and improved.

Our hope is that the use of alternatives to petroleum-based goods will encourage further innovation and perhaps even a revolution in composting. PLA is a relatively new technology in terms of mainstream usage and it has a great deal of promise if more people got behind it.

It’s wise to be wary of PLA’s limitations, but we should not dismiss it outright because the technology or systems to sort and compost it have not yet been perfected.

When I was a kid, very few people recycled, but today nearly every municipality has convenient recycling systems in place. While we’ve made real progress on that front, petrol-plastic usage and disposal is still not perfect. Some plastics can’t be easily recycled today, even here in San Francisco.

Corn plastic is not the “green bullet” some hype it to be. The technology needs improvement and it will take time to expand composting alternatives and create a convenient collection system that includes biodegradable plastics. What we really need to mainstream biodegradable plastic and other alternatives is a collective push for change. And change is what our environment needs right now.