By 1959, the USDA's Agricultural Research Service responded to the criticism by Carson and others with a public service film, "Fire Ants on Trial"; Carson called it "flagrant propaganda" that ignored the dangers that spraying pesticides posed to humans and wildlife. That spring, Carson wrote a letter, published in "The Washington Post", that attributed the recent decline in bird populationsin her words, the "silencing of birds"to pesticide overuse. The same year, the 1957, 1958, and 1959 crops of U.S. cranberries were found to contain high levels of the herbicide aminotriazole and the sale of all cranberry products was halted. Carson attended the ensuing FDA hearings on revising pesticide regulations; she was discouraged by the aggressive tactics of the chemical industry representatives, which included expert testimony that was firmly contradicted by the bulk of the scientific literature she had been studying. She also wondered about the possible "financial inducements behind certain pesticide programs".