Spraying "harmless plastic granules" in Afghanistan?

I have no idea what this is about, but all the vagary, classification, and departmental denials pique my interest.

In 2004, U.S.-contracted aircraft secretly sprayed harmless plastic granules over poppy fields in Afghanistan to gauge public reaction to using herbicides to kill the opium poppies that help fund the Taliban and al Qaida.

The mysterious granules ignited a major outcry from poor farmers, tribal chiefs and government officials up to President Hamid Karzai, who demanded to know if the spraying was part of a poppy eradication program. At the time, U.S officials up to the level of Ambassador Zalmay Khalilzad denied any knowledge of the program.

U.S. officials declined to identify the agency that oversaw the test spraying, but pointed out that the State Department oversees U.S. counter-narcotics efforts in Afghanistan. The department's bureau of international narcotics and law enforcement declined to comment. U.S. officials spoke to McClatchy Newspapers on condition of anonymity because the tests remain classified.

I don't know why I find this so curious....