FORT WORTH, TEX. ? Americans donated more than $4.2 billion to the Hurricane Katrina relief effort, topping the previous high of $3 billion donated after Sept. 11, according to a group that spent nearly a year investigating how donations were spent.

“That’s a massive outpouring of funding,” said Trent Stamp, executive director of Charity Navigator, the New Jersey-based nonprofit charity watchdog group.

Stamp and his staff reviewed tax and other donor records for about 1,000 charities, including the Red Cross, Direct Relief International and the Salvation Army, that collected donations for Katrina recovery efforts last year.

Most charities, he said, did the right thing with donations, providing needed services like shelters, food, water, ice, clothes and medical care at a critical time.

Some went beyond that, offering financial support, rebuilding homes, evacuating animals and helping rebuild arts communities. “The biggest problem was people wading into this who had no business participating,” Stamp said. “They thought they could do this, but they had no experience, no infrastructure.

“Those who failed, or didn’t deliver as thoroughly as they should have, were overwhelmed by the situation. They literally were on the ground in the way. And they raised money that could have gone to more reputable charities who had experience.”