A permanent memorial to honor Port Authority employees killed in the 1993 World Trade Center bombing and on September 11 has been installed at the World Trade Center — and a former Port Authority architect who worked on the reconstruction of the site brought it to life.

The 13-foot-tall sculpture is a 3D interpretation of a drawing created by Port Authority employees following September 11 that depicts the Twin Towers. The symbol was used throughout the Port Authority community, appearing on hard hats, patches, flags and other materials.

The memorial was financed by the WTC Memorial Fund in collaboration with the Port Authority and designed and engineered by the architecture firm HNTB, which had a personal connection to the project: members of their team previously spent decades working for the Port Authority.

“For 15 years, I worked on the reconstruction of the World Trade Center site with this symbol on my hard hat every day,” said architect Thomas Grassi, HNTB fellow and associate vice president, who served as project lead and architectural signatory. “To be asked years later to help give that same symbol a permanent physical form is deeply gratifying.”

Grassi was a Port Authority employee for 30 years and was working on the 82nd floor of One World Trade Center when the first plane struck. Beginning the following day, he spent the next 15 years supporting reconstruction of the World Trade Center site, and then joined HNTB in 2016.

The HNTB project team also included Roger Prince, who spent more than three decades with the Port Authority and serves as a trustee on the World Trade Center Fund board.

The new memorial will be installed at the southern end of the 9/11 Memorial Plaza and incorporates the names of Port Authority employees who died in the terrorist attacks on its base. The formal unveiling is scheduled for September 8 during an invitation-only ceremony.