DES MOINES (AP) - Federal environmental officials say the air in Parkersburg, a northeast Iowa town heavily damaged by a tornado last month, poses no health risk.

The U.S. Environmental Protection Agency has been testing the air in the town of about 1,900 for asbestos and other particulates.

The EF5 tornado that hit there on May 25 was the state's strongest in 32 years and spread debris throughout the area. Officials say it destroyed about 240 homes and damaged 400 more.

The EPA began its air monitoring activities earlier this month and says the efforts will continue as storm debris is transported.