Positives: 

1. Will degrade in commercial or municipal aerobic composting facilities in 6 months
   (As per ASTM 6400).
   Please note: these plastics will NOT degrade in landfills.
    

Negatives:  
 

1. Not sustainable- uses more fossil fuels than polyethylene as per “How Green are Green Plastics” in Scientific American”, Aug. 2000. The author states this belief on the cradle to cradle development of the product. Please consider the treatment of the soil before planting with a chemical, “Roundup”, which reportedly reduces the fertility of the soil; then the machine that plants the seed corn; then fertilization of chemicals; then the watering of the corn; then the harvest by machines; then the process where the corn is made into a finished product by shredding, heat, and fermenting the corn. NatureWorks’ website has an article that shows that their sustainability claims of using 68% less fossil fuel resources than traditional plastics are based on buying renewable energy certificates. (“Sams Club Partners with NatureWorks PLA to help the environment”, October 21, 2005.) See part of the article below. Follow the asterisk*
   
   NatureWorks PLA offers many other environmentally preferred benefits. From cradle to resin, its production uses 68 percent less fossil fuel resources than traditional plastics and it is the world's first greenhouse-gas-neutral polymer. *
   
   About NatureWorks LLC
   Based in Minnetonka, Minn., USA with manufacturing facilities in Blair, Neb., NatureWorks LLC, a stand-alone company wholly owned by Cargill Inc., is the first company to offer a family of commercially available polymers derived 100 percent from annually renewable resources with cost and performance that compete with petroleum-based packaging materials and fibers. The company applies its unique technology to the processing of natural plant sugars to create a proprietary polylactide polymer, which is marketed under the NatureWorks PLA and Ingeo™ fiber brand names. For more information about NatureWorks PLA, please visit www.NatureWorksPLA.com
   
   
   NatureWorks and the EcoPLA design are registered trademarks of NatureWorks LLC.
   
   *Based on the purchase of Renewable Energy Certificates by NatureWorks LLC.
   
   Also this lack of sustainability is noted in Popular Science, Sept. 2007, where they state that one should not take “eco claims at face value. Companies may tout the value of natural fibers without mentioning some of the unnatural methods used to produce them. Take corn and bamboo for example. Both have the potential to be green, but environmental concerns remain.” “Concerns: Energy from fossil fuels goes into producing pesticides, herbicides and fertilizer for corn.”
    

2. PLA will not degrade in landfills where most trash ends up. Normal plastics take hundreds of years to degrade in landfills. PLA which requires oxygen, moisture, and heat to degrade will probably last that long also.
    

3. Can break down in temperatures over 109 degrees such as in trucks or warehouses. (“Smart care program describes how to handle PLA containers” From Packexpo, May 19, 2006) Thus they require storage in temperature controlled warehouses and being shipped in temperature controlled trucks using more energy. A normal plastic does not need this kind of care.
    

4. Many have expiration dates of about 12 months.
    

5. Cannot be recycled with normal recyclable plastics. This has greatly affected plastic recyclers in the US according to articles in Plastic News. 
    

6. There are approximately 60 commercial or municipal compost facilities in the US that take food scraps which would include PLA. Most of these commercial or municipal compost facilities are in California and the Northwest –Oregon and Washington. Therefore it is safe to conclude that most biobased products do not end up in them when disposed of. Backyard composts, according to the Smithsonian Magazine, Aug, 2006, cannot break down PLA as they do not have high enough heat. (They require 140 degrees Fahrenheit and 90% humidity.)
    

7. The US is a “disposable” society. Recycling is a failure as only 8-10% of all plastics in the US are recycled according to the EPA. So the chances of biobased products being disposed of properly are slim. An article in California “Ventura County restaurants have nowhere to send biodegradable tableware”, March 20, 2009, illustrates the problem with PLA products. The restaurant owners want to do right by the environment by buying PLA products, but have no where to dispose of them so they end up in the landfill where they last as long as normal plastic.
    

8.  The extensive growing of corn for PLA and ethanol, instead of growing corn for cattle feed has caused the price of meat, chicken, pork, cheeses, flour, vitamins, and milk to go up. According to the Dept. of Labor, for the year ending in June, 2007, there have been increases from 10% to 13% in these products. A gallon of milk is at $4.00 a gallon where gasoline has dropped to $3.00 a gallon. Perdue and Smithfield Farms have both stated that the increase in cost of cattle feed has caused them to increase prices. Lance Foods announced on February 21, 2007 in an article in The Charlotte Observer, that there is less wheat being grown as farmers have switched to growing corn, thus increasing flour costs 30-40% in the last quarter alone.
    

9. The extensive growing of corn and the heavy fertilizing it requires has polluted aquifers in the Midwest according to the Salt Lake Tribune. The aquifers were also being depleted with the heavy watering needed for corn.
    

10. The nitrogen used in fertilizers for corn is also polluting rivers and the Gulf of Mexico. Corn requires heavy use of nitrogen in its fertilizing which has run off the fields into rivers and down the Mississippi into the Gulf of Mexico. This nitrogen feeds microscopic organisms that deplete oxygen levels as they die. The Gulf now has a dead zone 8,543 square miles according to Nancy Rabalais of the Louisiana University’s Marine Consortium. This area equals the size of New Jersey. And, unfortunately, this area is expanding. Nothing can live in this area including fish and shrimp. They suffocate unless they leave the area. Louisiana’s fishing industry is second only to Alaska. It has the largest catches of shrimp, oysters, and crawfish, according to state figures. The zone could be “catastrophic for the northern Gulf of Mexico’s $2.6 billion-a-year fishing industry” states Mike Rotta, program director at the Gulf restoration Network. “If this were happening in the middle of the country, people would be outraged,” he further commented. The dead zone has resulted in a 40% reduction in the number of licensed fishermen and shrimpers since 2001. The Chesapeake Bay has also been affected. (Taken from Bloomberg News, July, 2007 and the National Geographic, June 2008.)
     

11. The Franklin Associates, who does testing for the EPA, did a study in 2006 comparing High Density milk cartons versus PLA milk cartons. The results showed that the HDPE containers consume less energy, produce less post-consumer solid waste, and generate fewer greenhouse gas emissions than PLA milk containers. This was a life-cycle inventory analysis of half gallon milk cartons. Add to this the fact that milk cartons are frequently recycled, whereas, the PLA is not.
     

12. PLA is creating more global warming pollution than gasoline according to the Environmental Defense Org., November, 2007.
     

13. Most manufacturers of PLA use GMO plants which could adversely affect other plants.
     

14. GMO corn kills the larvae of beneficial pollinators, including the Monarch butterfly, and other beneficial insects. It fails, for example, to kill the African Cotton Worm, but kills the beneficial Green Lacewing that eats Cotton Worms. Insects develop resistance to the engineered Bt toxin over time, threatening to render natural Bt sprays useless for organic farmers — a tool allowed as a last resort.
    
    GMO corn threatens organic farmers and a sustainable environment. Pollen drift and genetic contamination reduce biodiversity. (Packaging and Plastics, July, 2006, by Natalie Reitman-White and Bob Doppelt
     

15. An article from the World Bank states that 75% of the increase in food prices is because of corn used for biofuels. The US claims of 3% are way off. One would also have to include any corn based plastics as they are also using corn that would normally be used for food. The Guardian; July 4, 2008, Aditya Chakrabortty
     

16. Smithfield Foods’ CEO C. Larry Pope, stated that the problems his company currently face are due to the high cost of corn, not to the recession. “Profits are down because of the recession. We’d be doing fine if corn prices hadn’t skyrocketed.” The Virginia-Pilot, Feb. 12, 2009. Smithfield was later sold in 2013.
     

17. There are currently 1 Billion people in the world that do not get enough food to eat every day. One in 6 people do not get a minimum of 1,800 calories every day according to the UN Food and Agriculture Organization. This is up from 11% from 2008’s 915 million people. Part of the reason? Food prices are up 24% from 2006 to 2008. (Alessandra Rizzo, Associated Press, June 20, 2009)
     

18. A Professor of Bio-Polymer Science and Engineering, Stephan Gilbert, stated that the use of certain bioplastics can come with “unwelcome ethical consequences”. Materials used to make bio-plastics such as cornstarch and sugarcane are important sources of food. By using these for packaging, food prices are being inflated in developing countries. Since some are not biodegradable in the soil and require special treatment for proper disposal, it makes little sense to use them in the first place.Guy Montague-Jones, Food Production Daily, Feb. 6, 2009,)
     

19. GMO corn fed to rats resulted in damage to several organs in the body: liver, heart, and lungs. (Natural Foods Merchandiser, Jan. 2010, “GM corn causes organ damage”. It only took 4 1/2 months for this damage to occur. This should raise red flags to consumers as the leaching that does happen with packaging, such as is the case of BHT, can happen with PLA. The study was published in the International Journal of Biological Science: “A Comparison of the Effects of Three GM Corn Varieties on Mammalian Health”, www.biolsci.org
     

20. Germany’s Institute for Energy and Environmental Research stated in June, 2009, that oil-based plastics, especially recycled ones, have a better life-cycle analysis than compostable plastics. This is due to biobased plastics having “less favorable environmental impact profiles than other raw materials examined.”
     

21. Soaring corn prices triggered hunger problems and riots around the world. An article quoted Frederic Scheer, CEO of Cereplast, that using corn for biofuels and biodegradable plastic products “could be an issue”. “You cannot have access to farmland without creating pressure on the food system.” Nov. 2010, “Scientific American”
     

22. Two million acres of grasslands in the US have been converted to growing corn in the years 2006-2011 thus increasing greenhouse emissions and increasing climate change.