Question answered - EPA approves Enlist Duo


Despite ample evidence illustrating the ability of 2,4-D (also known as 2,4-dichlorophenoxyacetic acid) to impact the delicately balanced thyroid system, and the uncertainty associated with the levels at which humans might be exposed to its increased use, the Environmental Protection Agency (EPA) announced its approval of Enlist Duo™ today. 

As I detailed in my last blogpost, Enlist Duo™ is the chemical combination of two herbicides: 2,4-D and glyphosate (the active ingredient in “Roundup®”).  Intended for use with corn and soy that have been genetically modified to be resistant to both herbicides, Enlist Duo™ is the chemical industry solution to our herbicide resistance problem.  In other words, to stop the growth of weeds that are resistant to single herbicides, farmers should just use more herbicide.  To continue the metaphor from my last post, by approving Enlist Duo™, EPA relied on the flawed logic of solving a problem with a problem, and let the old lady swallow the spider.

As NRDC has commented in the past (see our comments to USDA and EPA), Enlist Duo use has the potential to increase human exposure to 2,4-D - a worrisome trait given that scientific studies suggest that exposure to 2,4-D could increase the risk of birth defects, decrease fertility, and lead to improper thyroid functioning (normal thyroid function is critical for brain development and other metabolic processes).  

Enlist Duo™ should not have been approved for a host of reasons, including some that are directly relevant to human health, like:

  • Multiple streams of evidence (including molecular, animal, and epidemiologic studies) demonstrating adverse impacts of 2,4-D on the thyroid;
  • High potential for infants, children, and women of child-bearing age to be exposed to Enlist Duo™ via air, food, and water;
  • The complete absence of information on how the combination of 2,4-D and glyphosate will impact human and ecological health (including habitats for the iconic Monarch butterfly); and
  • EPA’s hopelessly out-of-date health risk assessment for glyphosate (the last EPA human health risk assessment for glyphosate was completed over 21 years ago).

In response to EPA’s inadequately protective approval decision, NRDC immediately filed a lawsuit challenging EPA’s decision to register Enlist Duo™.  By holding EPA accountable for its mission “to protect human health and the environment”, the NRDC suit seeks to protect the people, places, and populations (including Monarchs) that we all know and love.