Amy and Others,
The.3% limit was created many years ago before high CBD (hence higher THC) hemp did not yet exist. It was a number that was determined to definitely be below the threshold where a consumer of the hemp flower from the industrial hemp varieties would not be affected in any way.
It is the standard in many countries (the EU is .2%) and in Canada and I feel it is time to relook at it.
I posted an extensive paper publilshed in 2003 that hits on this at this link.