A look at history shows that in Europe specific THC limit values for industrial hemp were first determined in 1984. For the marketing years until 1987 a limit of 0.5 %, for subsequent marketing years a limit of 0.3 % was set. „Protection of public health“ was the justification for this decision.
This was in line with the proposals from science, originally it was also set to 0.5 %, then in 1976 Small and Cronquist used a concentration of 0.3 % THC (dry weight basis) to distinguish between „hemp” (non-drug Cannabis) and „marijuana” (drug Cannabis). Since then, the 0.3% THC limit value for industrial hemp has been used internationally. These values are also currently determined in Canada and the USA.
Surprisingly the regulation in the European Union were tightened up in 1999. The limit was lowered from 0.3 % to 0.2 %. This further lowering of THC level was justified to prevent the cultivation off illicit drug type Cannabis in industrial hemp fields. Yet no evidence was ever presented to support this opinion.
The aim of the European Industrial Hemp Association (EIHA) is now to restore the former, science-based and well-functioning THC limit of 0.3% for hemp crops.