The business magazine Fast Company is reporting that the EPA, perhaps erroneously, released a memo which “shows it knowingly allowed pesticide that kills honey bees.” A review of the report is not quite so dramatic as this pesticide is clearly persistent and highly toxic to honey bees at certain levels. However, toxicity alone is not a reason to withhold a pestcide’s EPA registration. In fact, most pesticides are highly toxic to invertebrates and insects. That is why they are pesticides. The real question is whether the pesticide poses a risk to honey bees when used according to the label. The report does outline some devastating and well-documented impacts on honey bees when the pesticide was improperly applied due to formulation errors (no “stickers”) or bad equipment (drill settings).

The part of the study that is most interesting is found on page 11 in which the EPA review team found that a previous field study that investigated the effects of clothianidin on whole hives had been erroneously classified as acceptable. According to the memo, the study does not satisfy guideline 850.3040 and “another field study is needed to evaluate the effects of clothianidin on bees through contaminated pollen and nectar.”

The memo does mention a Bayer study in which Clothianidin used to pre-treat seeds was “expressed” in maize seedlings and that honey bees were affected when they resorted to the seedlings for water supply. (page 54).

The implication is that it is possible that additional studies may need to be performed before the EPA and Bayer can say with certainty that clothiandin does not pose a risk to honey bees when properly applied and used or even that it is not the cause of honey bee colony collapse disorder.

It is also possible that plaintiffs or environmental groups may file to have the pesticide deregistered given the apparent confusion between the EPA’s current regulatory posture toward this pesticide and the contents of this report. The memo will make it challenging for the Justice Department to defend the registration.

This particular memo was written in response to Bayer’s request to approve the use of the pesticide on cotton and mustard plants. Clothianidin had sales of $262 million in 2009 according to the Fast Company article. It is used to pre-treat corn and other crop seeds. According to the Fast Company article, the EPA decided to proceed with expanding the registration despite the memo’s text and the recommendations, which seem to have stopped at precautionary labels. The memo is dated November 2, 2010 and was prepared by Joseph DeCant and Michael Barret, ecologist and chemist for the Office of Chemical Safety and Pollution Prevention.