Pesticide companies like Amvac Chemical have paid "volunteers" to drink or otherwise expose themselves to doses of toxic pesticides, including one derived from World War II nerve gases, often at levels far above those considered to be safe. Unlike patients in clinical drug studies, human subjects don't benefit from being dosed with toxic pesticides. That's one reason why human pesticide testing violates several international agreements, including the Nuremberg Code. Worse, a congressional analysis showed that companies repeatedly misled people about the nature of the pesticides being tested on them, dismissed negative test results, and failed to gain the proper consent of their volunteers. More PIRG info here.