More than 80,000 chemicals are produced and used in the United States. This is one of their stories.
Microwave popcorn -- what's in your bag?
Today's subject is another halogenated compound (others covered include triclosan, PCBs and PBDEs): Perfluorooctanoic acid, also affectionately known as PFOA, is perfluorinated, meaning that it consists of a chain of carbon atoms with fluorine atoms attached. It's sometimes called "C8" for short because of its eight carbons; its chemical formula is C8HF15O2.
Microwave popcorn bags are often designed with a coating of fluorotelomers, which, when exposed to high temperatures, break down into PFOAs, synthetic halogenated compounds that have been linked to health issues.
Within just a few years it was incorporated into the manufacture of fluoropolymers whose special abilities to resist water, oil stains, and fire helped make them a common component of clothing and furniture, including stain-resistant and non-stock coatings like Scotchgard, Teflon and Gore-Tex.
While PFOA is used to produce these everyday items, it's not supposed to actually show up in the finished product. Unfortunately it often does. And from there to the environment and your body is just a hop and a skip.
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As is the case of so many other halogenated organic compounds, the remarkable stability of PFOAs is also its curse. As best as we can tell, once PFOA enters the environment, it never breaks down. Consequently, PFOA is ubiquitous [pdf] throughout the environment -- on every continent, in the ocean, in fresh water systems, and in the bodies of animals around the globe. It's even a common component of household dust.
Studies indicate that likely pathways [pdf] for exposure from consumer items include food contaminated by packaging, dust inhalation or ingestion, and possibly direct contact with products treated with PFOA, especially carpets and the like.
No one should be particularly happy to learn that PFOA is coursing through one's veins, as the compound has been linked to a variety of health risks including cancer, liver disease, developmental problems and thyroid disease.
Things could have played out differently. Though PFOA first hit the marketplace in 1951, it escaped investigation under the Toxic Substances Control Act of 1976 (TSCA) which grandfathered in pre-existing chemicals. But as far back as 1961, a decade and a half prior to TSCA's passage, Dupont had evidence that PFOA posed health risks to its employees exposed to the chemical; unfortunately, the company failed to share such information with the Environmental Protection Agency as required by TSCA.
It wasn't until a class-action lawsuit against Dupont lodged by residents near a Teflon plant in West Virginia in 2001 that it became clear the chemical maker had withheld critical safety information for decades. (EPA also ended up suing and winning millions in damages, and 3M was also eventually fined. Read more about the legal wranglings here and here [pdf].)
The tide has now turned on PFOA. EPA states on its Web site that it "is not waiting for all of the answers to be known before taking action. ... In January 2006, EPA asked eight companies in the industry to commit to reducing PFOA from facility emissions and product content by 95 percent no later than 2010, and to work toward eliminating PFOA from emissions and product content no later than 2015." 3M has already phased out all production of the compound, and Dupont has pledged to do the same by 2015.
The phase-out appears to be paying off: though the chemical shows up in the vast majority of Americans' blood, its levels are already declining. Problem solved, right? Not quite. And that's the other half of the PFOA story.
Fluorotelomers are another class of halogenated compounds with seemingly magical properties. One of those is its lipophobicity -- a really great technical term for something that repels oils and fat. If you've got a surface that you don't want to get stained, fluorotelomers are a great solution. And if you're using paper with fatty, oily foods, a layer of fluorotelomers will keep the paper clean and crisp.
An ideal place for fluorotelomers is a microwave popcorn bag. A coating of that stuff will keep the butter and oils on the popcorn where you want it and not in the bag where you don't. Ingenious. Except there's a problem.
Expose fluorotelomers to high temperatures and they break down into PFOAs. So every time you crunch on microwave popcorn you are more than likely munching on a little PFOA. Yum. How much? Well, if you eat just one bag of microwave popcorn per week, it's estimated that you'll receive enough PFOA to maintain levels found in the average American's blood. (Further reading here and here [pdf].)
Is that something to worry about? EPA doesn't recommend alarm: "Given the scientific uncertainties," its Web site reads, "EPA has not yet made a determination as to whether PFOA poses an unreasonable risk to the public, and there are no steps that EPA recommends that consumers take to reduce exposures to PFOA." In the meantime, as noted above, the agency is asking the manufacturers of PFOA to cease and desist.
If that doesn't give you the warm fuzzies, you might reconsider your popcorn source.
There is reportedly microwave popcorn out there that doesn't use fluorotelomers (if you know which, tell us in a comment), and it's been rumored that old-fashioned, stove-top popping still works, as does air-popping. Then there's always the do-it-yourself microwave method -- make your own bag or skip the bag and just pop it in a glass bowl and plate (ideas for DIY popping can be found here, and you might find this info from NASA on how popcorn pops useful).
Next time you're in the mood for one of America's favorite snacks, the choice is yours -- as you load your bags in the chemical marketplace, it's always good to know what's loaded in the bags.
Crossposted with www.thegreengrok.com.
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