This question cannot be answered in general. In any specific case it would depend on the degree of risk as well as the range and severity of possible harm that could come from it. Also the value of the testing would have to be taken into account. A test that did not need to be made would not be ethical even if the risks and dangers were quite small. However, if some degree of exposure is unavoidable by those whose job it is to handle it, then some carefully controlled testing might be ethical. Of course in any such testing it is assumed that the subjects are completely informed of all possible risks and that the subjects are capable of understanding these risks. If those conditions cannot be met, then the testing is unethical.
That’s interesting. You’re right, but I was thinking along different lines than that. These are low dose, no effect level tests, which are not what I was considering.
That was my point. If you are looking for one black and white answer that will cover all instances of “testing pesticides on humans”, you are not going to find it. The question cannot be answered without delving into the particulars of the instance in question.