It has been contended that assuming current money saving advantage examinations had been applied to choices, for example, regardless of whether to order the expulsion of lead from gas, block the development of two proposed dams simply above and underneath the Grand Canyon on the Colorado River, and control laborers' openness to vinyl chloride, the actions could not have possibly been executed [albeit all are considered profoundly successful].[39] The US Clean Air Act has been refered to in review studies as a case in which advantages surpassed costs, however information on the advantages linferable generally to the advantages of lessening particulate contamination) was not accessible until numerous years later,[39]