A first-of-its-kind retrospective study concludes that environmental cleanup projects can provide high value to society, making them economically viable alternatives to coastal development projects. The analysis of Boston Harbor suggests the capitalized value of restored ecosystem services now stands at between $30 and $100 billion—far outweighing the $5 billion cleanup cost. Published in Frontiers in Marine Science, the study demonstrates that the post-cleanup value of healthy ecosystems and their associated benefits should be considered when evaluating options for coastal areas.