Huron Portland Cement Company v. Detroit 362 U.S. 440 (1960)
HURON PORTLAND CEMENT COMPANY v. DETROIT 362 U.S. 440 (1960)
In a case involving a major commerce clause issue, a 7–2 Supreme Court sustained Detroit's Smoke Abatement Code. That city sued a Michigan manufacturer operating ships in interstate commerce for violating its air pollution regulations. The manufacturer stressed its adherence to congressional regulations, claiming that Detroit could not impose stricter standards. Justice potter stewart's opinion, devoted primarily to rejecting claims that federal laws had preempted the field, accorded a high priority to the state police power. Exercise of that power must stand unless clearly discriminatory or violative of national uniformity, and nothing "suggest[s] the existence of any … competing or conflicting local regulations."