While responsible for the structural engineering on a large number of prominent buildings, including Boston City Hall, the Federal Reserve Bank of Boston, the Singapore Treasury Building and Dallas Main Center, LeMessurier is perhaps best known for a structural controversy. As the result of the questions of a student, LeMessurier re-assessed his calculations on the Citicorp headquarters tower in New York City in 1977, after the building had already been finished, and found that the building was more vulnerable than originally thought (in part due to cost-saving changes made to the original plan by the contractor). This triggered a hurried, clandestine retrofit which was described in a celebrated article in The New Yorker. The article, titled "The Fifty-Nine-Story Crisis," is now used as an ethical case-study.
LeMessurier died in Casco, Maine on June 14, 2007 as a result of complications after surgery he underwent on June 1 after a fall the day before.