During part time, he worked as a volunteer EMT with the voluntary ambulance in Brighton, New York.

[1] Following the collapse of the South Tower, Zeng, due to his EMT experience, collected medical supplies from his office and informed his colleagues that he was heading to World Trade Center site to help the rescue workers and aid the injured.

[1][4][3][5][6] Zeng was killed when the North Tower of the World Trade Center collapsed at 10:28 a.m.[2] In May 2002, he was posthumously awarded certificate of commendation by the Governor of New York George Pataki.

Memorial services honoring Zeng were also held in Fengqing Shouyue Primary School and his alma mater No.

[7] In December 2003, Manhattan Community Board #3 passed a motion to name a block in Bayard Street in New York's Chinatown as Zhe "Zack" Zeng Way.