Department of State's Comments on EPA August 19, 2002 Letter

The Department wishes to respond to three concerns raised by the EPA in its August 19 response to Secretary Powell. First, EPA expressed concern about the level of eye toxicity of the glyphosate formulated product which the Department has been using in the aerial spray program in Colombia (e.g., EPA Response at pp. 2, 33). Secondly, EPA replied that it could not evaluate the toxicity of the tank mixture (glyphosate formulation, water, surfactant) as sprayed in Colombia because the Department did not supply toxicity tests on that mixture (e.g., EPA Response at pp. 2, 33). These two concerns prompted EPA to recommend "that DOS consider using an alternative glyphosate product (with lower potential for acute toxicity) in future coca and/or poppy aerial eradication programs." (EPA Response at p. 12) Finally, EPA raised questions regarding the potential for spray drift to legitimate crops from aerial eradication (e.g., EPA Response at p. 59).

Glyphosate formulation:

As this report was being prepared, the Department has worked with its supplier of glyphosate to identify a slightly different formulation that is less of an eye irritant because it uses a different inert surfactant. This formulation is also known to have as low or lower toxicity ratings in all other categories as well. Although this alternative formulation has only recently been registered in Colombia, it has been extensively tested and widely used elsewhere, including the U.S., and is registered for non-agricultural use in the U.S. by the EPA.

This alternative formulation addresses EPA's concern in its response to the Department of State. The Department plans to switch to this alternative formulation for use in the aerial spray program in Colombia as soon as the alternative formulation can be manufactured, purchased, and delivered.

Toxicity tests:

EPA indicated that it could not verify the potential toxicity of the spray mixture: the glyphosate formulation diluted with water and fortified with additional surfactant. The Department has commissioned toxicity tests of the spray mixture being used in Colombia. The most relevant portion of the studies has been completed; it confirms that the risk of eye irritation is low to persons not handling or mixing the concentrated glyphosate formulation. The Department also expects the full tests to demonstrate that this mixture poses no health risk for humans. The EPA-certified laboratory that is performing the studies is doing so in a professional, scientific manner, which has required a considerable amount of time. The results will be forwarded to the Committees, and to the EPA, as soon as the Department receives final copies of the studies.

The Department has also commissioned toxicity tests for the spray mixture using the alternative glyphosate formulation discussed above. These will be performed as soon as that formulation is available for mixing in field conditions.

Spray drift:

The EPA used a computer model to indicate a possibility that non-target plants hundreds of feet away might be exposed to a fraction of the glyphosate application, depending on spray droplet size and wind conditions. USDA scientists and the Colombian Environmental Auditor to the spray program regularly look for evidence of spray drift as part of ground truth verification missions. These experts, who actually go to the fields, have concluded consistently that evidence of spray drift is rare. Post-spray field visits indicate that if this drift occurs, it is most often in trace amounts that have no observable adverse consequences on non-target plants.