Oil Spill Won't Hurt National Economy: Report

May 20, 2010 — -- As big as the Gulf of Mexico oil slick is, it won't have a major impact on the national economy, according to a new report by Moody's Economy.com.

The oil spill caused by the explosion of the Deepwater Horizon oil rig last month is hurting businesses in areas of Louisiana, Mississippi, Alabama and Florida -- but those places represent only 1 percent of the gross domestic product and national employment "so broad macroeconomic effects are unlikely, at least in the near term," the report said.

The spill's impact, locally, however, will be uncertain. According to Moody's Economy.com:

"If the spill reaches coastal waterways where the marine life hatches and develops, the industry could face years of disruption," the report said.

Fish caught in the region -- mostly shrimp and oyster harvest -- is worth nearly $400 million per year dockside. The retail value of the catches, however, is much greater.

The port of New Orleans is most at risk, but if the slick continues to move west, it also could hurt operations near the port of Morgan City, La. Cargo moving through the two ports accounts for just under 7 percent of total U.S. waterborne cargo shipments.

BP, the owner of the oil well where the rig was based, has said it has spent $350 million in cleanup costs so far. Exxon spent a total of roughly 11 times that much on its cleanup of the infamous Exxon Valdez oil spill of 1989.

The Gulf of Mexico spill and its expected economic impact often have been compared to Exxon Valdez, but a number of other spills in the years following Exxon Valdez also have taken heavy tolls on economies around the globe.

On the following pages, ABCNews.com takes a quick look at some of the biggest oil spills to damage bottom lines since 1989.