The most controversial decisions of the INCB are those in which it assumes the power to interpret the Single Convention. Germany, the Netherlands, Switzerland, and Spain continue to experiment with medically supervised injection rooms, despite the INCB's objections that the Single Convention's allowance of "scientific purposes" is limited to clinical trials of pharmaceutical grade drugs and not public health interventions. These European nations have more leverage to disregard the Board's decisions because they are not dependent on licit psychoactive drug exports (which are regulated by the Board). As international lawyer Bill Bush notes, "Because of the Tasmanian opium poppy industry, Australia is more vulnerable to political pressure than, say, Germany."