Regulation can produce a 'regulatory U-turn' where a rule passed in the name of a goal (e.g., clean air) produces the opposite outcome at higher cost: the 1970s Clean Air Act amendments mandating scrubbers on new coal plants led utilities, indifferent to coal type once a scrubber was required, to keep burning cheap dirty Eastern coal, so some pollution still escaped while costs soared—whereas using clean Western coal would have produced cleaner air without expensive scrubbers.