can anyone tell me which / what is the highest adr qualification available? ie how high does the classes go?
Try reading this–
http://www.hse.gov.uk and put dangerous goods inthe search box
this is where the list of dangerous goods is shown in their classes.
-Carriage of Dangerous Goods Manual - Classification
You will need to read through this site and take note then of what segment of information is of intrest to you.
cheers mate 