The city’s Landmarks Preservation Commission is formally considering landmark designation for 70 Pine Street — one of Lower Manhattan’s great Art Deco towers and a skyline fixture since 1932.

When a building is granted official city landmark status, it may not be demolished or altered without the commission’s approval.

The 66-story edifice, previously owned by AIG, was designed by architects Clinton & Russell, Holton & George. The tallest building downtown since the fall of the Twin Towers, it’s the only major skyscraper of its era that does not yet enjoy landmark protection — unlike Donald Trump’s nearby 40 Wall St., and the Empire State Building and Chrysler Building uptown.

The Landmarks Commission has “calendared” a public hearing on 70 Pine St. for May 10. The hearing doesn’t necessarily mean the panel will make a designation, but it’s the first step in the process toward doing so. The panel will consider proposals to landmark not only the tower’s exterior, but also the Deco-style first floor interior.

AIG sold 70 Pine St. to New York developer Youngwoo & Associates in 2009. Youngwoo plans to lease the lower floors to offices and convert the upper portion to luxury condo apartments.