On April 20, the US Environmental Protection Agency (EPA; Washington, DC) rejected a petition filed by the environmental group Greenpeace in January calling for the revocation of current licenses for Bt transgenic crops. The day before EPA's announcement, anticipating the rejection, Greenpeace released a report criticizing the research EPA subsequently cited in defending the licensing process, claiming that the agency “acknowledges that Bt crops could pose risks to monarch butterflies.” Although the EPA did refer to additional research done since the original licenses were granted, including a highly publicized laboratory study that suggested that pollen from Bt transgenic corn might be harmful to monarch butterfly larvae (Nat. Biotechnol. 17, 627, 1999), an EPA source familiar with the situation said that that study was cited only to explain voluntary measures implemented in 2000 to reduce butterfly exposure to Bt crop pollen while field studies continue. Despite the apparent misinterpretation, Ellen Kramer, an EPA spokesperson, says the agency does not plan to engage in a public relations battle with Greenpeace. The petition was part of a lawsuit filed against EPA by Greenpeace in 1999.