Hi again Tom,
Sorry, now I see where you are going, you would not be able to drink water treated with ClO2 if it had no test data in relevance to human toxic effects, so you will see from the sites below how that is done, human testing has been done for this!
If you dont want to read all the third one CIADS (Concise International Chemical Assessment Documents) is ago one to read as it takes information from the WHO, EPA etc to form it's evaluation.
The forth is the EPA standards and test requirements for using ClO2 and amount of treatment plants, they also show the results of those tests and list any plant or reading problems that occurred during the 12 month period