(FORTUNE Magazine) – How much is America overpaying for environmental regulations? Robert Crandall, a senior fellow at the Brookings Institution, reviewed a score of serious efforts to quantify the costs since the early 1970s. His paper, published by Washington University's Center for the Study of American Business, suggests that the excess could amount to several hundred billion dollars a year. / The most comprehensive estimate puts the total cost of federal air and water legislation in 1990 at some $320 billion. Economists Michael Hazilla of American University and Raymond J. Kopp of Resources for the Future, anenvironmental research group, found $79 billion in direct costs; the balance came from curtailed job growth, lower saving, and reduced capital formation. The reallocation of resources, they calculate, reduced GDP by 5.8%. And the costs are growing every year. Hazilla and Kopp did not try to figure out what portion of the costs were excessive, but other studies provide clues. The 1990 legislation to ease the putative damage of acid rain was passed despite a $500 million study by the National Acid Precipitation Assessment Program (Napap) -- funded by Congress itself -- that found only negligible damage. Napap research director J. Laurence Kulp calculates the cost at $4 billion a year -- and benefits at just $100 million. New fuel and auto emission standards could cost $2 billion to $6 billion annually, according to the Office of Technology Assessment. Yet only 12 million people -- all in California -- suffer from elevated smog levels for more than 100 hours annually. Most other problem areas could meet EPA levels by cutting emissions just one or two days per year. Regulations for solid-waste disposal and toxic waste cleanup cost an estimated $5 billion to $9 billion a year. If they prevented half of the additional 1,100 cancers the EPA estimates these wastes cause annually, Crandall estimates, the cost per case avoided would be $10 million to $18 million. Why do legislators do these things? Crandall, though a certified moderate, speculates that it's ''a desire to purge ourselves of guilt for succeeding too well in taming nature.'' In other words, some people just want to curb growth.