It’s a good question. The Port Authority of New York & New Jersey is responsible for rebuilding the World Trade Center. They have an internal audit group and they may be doing some audits of the construction projects. Those audits serve the management of the Port Authority and most likely are not public.
The New York State Comptroller though is supposed to be serving the public’s interest and has not yet issued any reports on the construction work that is occurring. As one of the world’s largest construction project, it rightfully should be audited by the State Comptroller.