WASHINGTON - Within five months of the crash of TWA Flight 800 in 1996, the National Transportation Safety Board suggested a federal regulation to address the fuel tank explosion that caused the jet's destruction.

But for the next 12 years - until yesterday - that regulation was delayed by a stiff wind from the hard-pressed airline industry, complaining about the rule's cost and technical practicality, say safety experts.

Just weeks ago, on April 28, airline industry lobbyists met White House regulatory officials at the Office of Management and Budget, records show, to make one last pitch with a 15-page presentation.

The Federal Aviation Administration should withdraw the rule because "it has not made a 'reasoned determination' that the proposal's benefits outweigh its costs," said Air Transport Association lobbyists.

Yet this time, unlike many other occasions in the past dozen years, federal policymakers were not swayed: the new rule requires what the lobbyists opposed - filling a tank with nitrogen to prevent ignition of gas vapors.

That's because of the dogged efforts of the families of the victims, said Jim Hall, the safety board's chairman at the time of the crash.

"It's a credit to them that any rule, even this particular rule, was passed," said Hall, who later advised the families.

James Hurd, a leader in Families of TWA Flight 800 Association, whose son died in the crash, said, "We just kept calling until we got some people started making changes."

As for the delays, Hall said, "It is the typical Washington at its worst."

"The driving fact of why it took so long was that the cost-benefit analysis had not tilted very hard to saving lives," Hurd said.

Two FAA panels, dominated by industry, reached the same conclusion: fuel tank inerting, used by the military, was too costly and impractical.

The industry preferred to deal with the source of the ignition, the wiring. Even after two FAA engineers made a breakthrough in 2002, finding a less expensive system, most of the industry balked. Only Boeing, whose plane exploded in 1996, embraced it.

Airbus and the European Union objected to the proposed FAA rule. Airbus said its planes were made differently from Boeing's and were not vulnerable in the same way.

Former NTSB managing director Peter Goeltz said, "I think it was a matter of cost. The industry understands this is a rare event and they would prefer not to spend the kind of money that this is going to take to eliminate a rare event."

In 2004, the FAA announced it would propose a rule, but waited until the end of 2005. The comment period was extended in 2006 as airlines and manufacturers lobbied against the rule as too costly.

Rep. Tim Bishop (D-Southampton) became so exasperated, he inserted language into the 2007 House FAA authorization bill requiring the FAA to issue the rule.

Finally, in April, the OMB opened its review, meeting with industry and the families.

"If they had another explosion, we told them of what sort of damages that really does to a family and to people themselves," Hurd said.

Hall said, "I welcome this. But I also welcome it with the reality that by the time it is implemented, it will have been 20 years since TWA 800."

Staff writer Bill Bleyer contributed to this story.