On an average day, a dozen giant freighters ply their way in and out of New York City's busy harbor to load and unload some 150,000 tons of goods, from electronics to automobiles. But Sept. 11 was not an average day, and for the New York Shipping Association, Inc., a cooperative headquartered on the 19th and 20th floors of the World Trade Center, it proved the ultimate test of the nonprofit's eight-year-old disaster recovery plan. In 1993, when terrorists with a truck bomb first tried to destroy the twin towers, NYSA—which coordinates the work assignments of the city's 2,900 longshoremen—was nearly forced to shut its doors for good: The nonprofit hadn't saved its computer data, some of its employees panicked and momentarily disappeared during the evacuation and some ships languished at their piers, others idled at anchor outside the harbor, and still others were diverted elsewhere, costing local shipping companies millions of dollars.

Not this time. Within 24 hours of the attack on the World Trade Center, all of NYSA's some 160 employees were back on the job in emergency offices in Jersey City, N.J., just across the Hudson River, and in Philadelphia. By Thursday morning, 48 hours after the attack, when the harbor was reopened to commercial shipping, NYSA was once again helping such companies as the Bermuda Container Line Ltd., China Shipping Agency Co., Essex Cement Co. and more than 70 other member organizations load and unload freighters. NYSA is still searching for permanent quarters, but the results so far look good. Says Executive Vice President James Melia: "After the 1993 bombing, it took us five weeks to get back in full operation. After that, we changed the way we do disasters."

How did the association do it? Having a good disaster plan in place certainly contributed much to NYSA's success. But nobody could anticipate the complete collapse of both towers. "I remember sitting in on a discussion this summer on how we'd handle a floor fire," says Kenneth Lepczyk, NYSA's IT manager for applications, who led the association's evacuation and is helping it sprint back into business. "Someone asked, 'What if the whole building blew up?' and I said, 'Yeah, right.'"

Indeed, just as critical, in the view of NYSA executives, was the group's culture: its employees, toughened by their experience in the 1993 attack, and its management, whose single-minded goal was to protect its people first, then worry about the technology. Some companies may let their workers take lunch during a disaster drill, but not NYSA. "We made attendance mandatory and made sure people knew what to do if they ever had to get out fast," Lepczyk says.

The day began routinely enough. NYSA's first shift of workers—those who track ships in the harbor and then determine which workers are needed at which terminals—were already up on the 20th floor of the World Trade Center, working the early shift since 7 a.m. Some 120 more back-office workers, who process benefit checks, vacation pay, pension and welfare payments to longshoremen, were just starting to arrive on the 19th floor to start work at 9 a.m., when Lypczyk felt a sharp jolt.

"I was in someone else's office on the 19th floor on the east side of Tower Two when it happened," he recalls. "I ran around to my office on the north side and saw Tower One engulfed in flames." Lepczyk, the association's highest-ranking executive on the floor at the time, sprang into action on the 19th floor. He called his colleague, IT systems manager Joseph Strcich, working on the floor above, and both began ordering all of NYSA's employees out of the building, turning away those just arriving at their desks. It was the first step in a disaster drill NYSA had run through countless times as part of its regular emergency operation plan. "We had everyone into the stairwell within 90 seconds," Lepczyk says.

Once down in the mezzanine-level lobby, Lepczyk and Strcich ordered the group to ignore World Trade Center security personnel, who were telling people that with debris and bodies falling from Tower One, they should return to their offices and stay there. Lypczyk recalls hearing a voice on the public address system urging people to "Go back up to your offices." As they searched for the safest lobby exit, Lepczyk recalls, "There was another huge explosion and the building shook even harder." It was about 9:15 a.m., and the second plane had just hit Tower Two. "I looked at Joe and said, 'Let's get our people out of here—now.'"