Twelve hundred more hurricane-destroyed houses in South Mississippi will be torn down under looser asbestos-handling requirements thanks to a federal extension granted late last week.

The U.S. Environmental Protection Agency-approved No Action Assurance runs until Sept. 30 for houses in Hancock, Harrison, Jackson and Pearl River counties. About 4,200 residential structures will have been demolished when the extension ends, officials at Mississippi's Department of Environmental Quality said.

The MDEQ regulates air emissions of asbestos from building demolition and renovations for the state.

"We appreciate the efforts of the EPA in recognizing the continued need for this flexibility," said Trudy Fisher, MDEQ executive director. "This flexibility has substantially helped the progress of hurricane recovery efforts along the Mississippi Gulf Coast, and its continuance is necessary to ensure the current pace toward recovery."

The looser regulations mean county and city governments do not need to examine each structure they allow to be torn down for asbestos if the structure appears to be unsound. They can also fill out one set of paperwork to demolish entire streets or subdivisions, said Maya Rao, the chief of DEQ's air division.

Rao said months of monitoring by EPA during the heaviest demolition phase on the Coast showed no asbestos was being released into the air.

Bickham Forshee, DEQ's asbestos section supervisor, said demolition contractors will still need to follow worker safety guidelines for handling asbestos and a supervisor certified to work with the material will need to be on the job site. Asbestos is a natural mineral fiber that has been shown to cause cancer and lung disease.

"Most houses are going to have some asbestos because it's in more materials than you would realize," Forshee said. "We will be having a weekly presence on the Coast monitoring for it."