Just days before a huge downtown marathon, Centennial Olympic Park officials said Tuesday they will have to dig up grass in some parts of the park to remove glass blown there by the March 14 tornado.

About one to two inches of sod will have to be replaced in an area of roughly 33,000 to 36,000 square feet, or less than an acre, right across the street from the Omni Hotel at CNN Center, said Mark Banta, general manager of the park.

Glass from the hotel's shattered windows has become embedded in the soil and efforts to remove the shards with high-powered vacuum machines have not worked.

"It's about the only way to guarantee we won't have glass in the grass," said Dan Graveline, executive director of the Georgia World Congress Center, which oversees operation of the park as well as the Georgia Dome and the convention center.

The ING Georgia Marathon is scheduled to be held at the 21-acre park on Sunday. About 15,000 runners are expected to participate.

Banta said the sod removal will not affect racers, who will be at the end of the park near the Georgia Aquarium and the World of Coca-Cola. The sod to be replaced runs from the fence at the park's north end to the amphitheater near the fountain of rings.

"We will have the area blocked off by barricades, and it will be clearly identified," Graveline said.

GWCC officials broke the news during a meeting Tuesday of the GWCC Authority, the governing body for the campus. Graveline updated authority members about physical damage from the storm, its impact on upcoming conventions and how it will affect the bottom line for the park, convention center and stadium.

He said despite losing or postponing some smaller events, large trade shows are still on the calendar. Two big events, The Atlanta Journal-Constitution International Auto Show and the FIRST student science competition, will go on as scheduled, said GWCC spokeswoman Katy Pando.

Graveline also said he hopes the facility can break even at the end of the fiscal year. "We have some hurdles to cross before I can guarantee this, but I think that's pretty amazing considering where we've been," he said.

Officials at other business affected by the storm said Tuesday they're also making progress.

At the Equitable Building, replacing the first of the 300 blown-out windows is under way, according to a statement released by building officials.

The window replacement project at the Georgia-Pacific Building is expected to begin today, said James Malone, Georgia-Pacific spokesman. He said the entire process will take 10 to 12 weeks.

The Westin Peachtree Plaza hotel probably will not begin to replace plywood with glass for another six to eight weeks, hotel general manager Ed Walls said.

Staff writer Ken Sugiura contributed to this article.