The monthly board meeting of the Port Authority of New York and New Jersey will mark a milestone for the powerful bistate agency.

Thursday's session will be the first board meeting held at the World Trade Center site since shortly before the Sept. 11 attacks leveled the trade center towers. Among the nearly 3,000 people killed that day were 84 Port Authority employees.

The Port Authority's new offices in 4 World Trade Center overlook the Sept. 11 museum and memorial pavilion. Agency officials say the human resources department set up a program to ease the transition for employees, some of whom had concerns about returning to the trade center site.

The agency moved to offices on Park Avenue in Manhattan after Sept. 11.