Bio-based Chemicals: When Green is Toxic
Compostable cups. The PlantBottle. Polyethylene plastic from sugar cane. Bioplastics and other biobased chemicals – made from plants rather than petroleum – can slash a product’s carbon footprint.
Brand owners are driving demand for bioproducts to help meet corporate sustainability goals. And biobased makes economic sense as a hedge against the high price of crude and volatile fossil fuel markets.
But is bio-based enough? Consumers want safer products too. Simply replacing the carbon from oil with carbon from plants won't necessarily make a product safer, if the chemical in question is hazardous to health. If toxic petrochemicals are made with renewable biomass, will customers revolt? Let’s explore the challenge.
Ten years ago, Cargill launched NatureWorks to convert cornstarch to polylactic acid (PLA), the first biopolymer to compete head-on with petrochemical plastics and fibers. PLA scored so well against all 12 principles of green chemistry that the U.S. Environmental Protection Agency gave the company a prestigious national award for environmental safety.
Since then, biobased demand has exploded. Although just a few percent of all plastics are biobased today, analysts predict rapid annual growth will claim 20 percent market share within a decade. Getting to 90 percent is already technically feasible.
Major Benefits to Climate
Turning plants into products can reduce our dependence on fossil fuels in two ways. Manufacturing PLA produces 60 percent less greenhouse gases than the petrochemical plastics such as PET and polystyrene. Life cycle assessments show similar reductions for other biobased chemicals.
But bioproducts reap even greater climate benefits upstream of the production process. Biomass has a material carbon footprint of zero. That’s because plants fix carbon dioxide from the atmosphere in roughly the same timeframe (years) that greenhouse gases are released at the end of the useful life of bioproducts. But petrochemical products are made from fossil feedstocks formed millions of years ago. The eventual disposal of petro-products adds to man-made climate change.
Consider the material carbon advantage. Every hundred pounds of biopolymer that replaces fossil-based polyethylene avoids 314 pounds of carbon dioxide emissions over the life of the product. Substituting for petrochemical PET reduces greenhouse gas emissions by about 230 pounds.
Although the climate gains are real, the market rush to bioproducts has raised some old questions and a new concern.
Out with the Old Questions …
Some have questioned whether biobased materials from agricultural crops can ever be a truly sustainable feedstock. From energy intensive land use and chemical inputs to rising food costs, they argue that the benefits are marginal or worse.
Those concerns may be valid for biofuels such as ethanol. But biobased plastics and chemicals used in consumer products are materials, not fuels. The petrochemicals they aim to replace only account for about five percent of oil and gas consumption. And the next generation feedstocks, such as forest products and agricultural waste, are more sustainable than food crops.
Others have raised end-of-life issues. Some bioplastics are biodegradable, but too few systems exist to collect and compost those products when they become waste. And only about 10 percent of plastics are currently recycled. But those infrastructure gaps plague all compostable materials and all plastics; you can’t really blame bioproducts.
… in with the New Concern
Instead, I want to raise a brand new concern about bioproducts. Left unchecked, the emerging biobased chemicals industry could repeat many of the toxic chemical mistakes of the 20th century. That’s because just about any toxic chemical can be made from biomass instead of oil or gas. Two related trends trouble me.
First, the federal government lacks meaningful authority to regulate chemicals. Everyone agrees that the 37-year old Toxic Substances Control Act of 1976 (TSCA) is obsolete. Yet, Congress has repeatedly failed to fix our broken federal chemical safety system. Relentless opposition by toxic chemical manufacturers has thwarted passage of the Safe Chemicals Act. Until TSCA reform succeeds, toxic petrochemicals will largely get a free ride, with few questions asked.
Second, the emerging biobased chemicals industry has targeted drop-in replacements for existing chemical markets rather than new biobased molecules. That’s because building markets for new biopolymers like PLA remains too expensive in the short run for many.
A nasty synergy is brewing. Existing toxic petrochemicals are unfairly favored under our broken regulatory system. Now industry seeks to make those very same chemicals except with biomass instead of petroleum. Meanwhile, market barriers and lax regulation discourage introduction of new greener chemistries.
So far, the rush to renewable chemical feedstocks has largely ignored the health and safety profile of biobased materials across their lifecycle.
Industry applications raise concerns
Plans to produce biobased PVC plastic provide an extreme example. To make PVC, the poison plastic, add two carcinogens, pump the resin full of toxic additives and leave a trail of chlorinated waste from production and disposal. Replacing the petroleum in PVC with renewable carbon hardly greens its lifecycle.
The current pursuit of biobased PET plastic raises a similar concern. In Coca-Cola’s breakthrough PlantBottle, only 20 percent of the carbon is renewable. The bottle is PET plastic but with just one biobased ingredient made from sugar cane. The rest is fossil carbon from p-xylene, a hazardous chemical linked to brain damage in newborn animal studies.
A race is underway to produce biobased p-xylene to meet brand owner demand. In 2011, Coca-Cola announced a plan to bring a 100 percent bio-PET bottle to market. To get there, they launched a new Plant PET Technology Collaborative with Nike, Procter & Gamble, Ford and Heinz.
Biobased toxic chemicals are not the answer. As a society we need to design chemicals and chemical processes that are inherently safe for public health and the environment.
Tips for Business
Counting myself as one of the new biobased enthusiasts, I have some sage business advice for my fellow travelers among the brand owners, start-up biobased companies, agricultural giants and biobased divisions of major chemical manufacturers.
Apply a green chemistry lens to your target market and material selection. Use the GreenScreenTM or similar tool to benchmark the hazards associated with the chemicals you aim to replace with biobased substitutes. Avoid chemicals of high concern entirely. Think twice about making major investments in other chemicals of concern. Such markets will not be sustainable once public awareness and regulatory attention catch up to you, even when these chemicals are biobased.
Support the Safe Chemicals Act to ensure meaningful TSCA reform. The existing law unfairly grandfathered in most toxic petrochemicals without scrutiny when it passed. Chemical policy reform is inevitable, driven by a patchwork quilt of state policies and chaotic market movement away from toxic chemicals. When federal reform finally breaks, a backlog of demand for meaningful chemical regulation will sweep the nation. If you’re caught behind the regulatory curve, your market share may be washed away, regardless of whether it’s biobased.
The real business opportunity lies in products and materials that are both renewable and safe for people and the planet across their lifecycle. By advancing biobased green chemistry, industry can ride two waves longer, and avoid being wiped out by the inevitable cross current of consumer alarm and toxic regulation.
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