Regarding the "alcohol seriously impairs an operator's judgment" example, is it right to say that the referential 'that' is referring to the whole clause: "alcohol seriously impairs an operator's judgment"? It seems to me that this is a claim about the capacity of alcohol to impair judgment, which is not in and of itself that which poses a threat to the team's safety. Rather, the serious impairment of the operator's judgment in itself poses the threat. I appreciate any clarification.