Government health officials have estimated that as many as 1 million people may have been exposed during three decades of water contamination going back to 1957, a situation examined in a recent Associated Press investigation. The numbers include Marines in barracks and military families living on the sprawling Atlantic training and deployment base, and civilians who worked there.

Base officials hand-carried letters Wednesday to 900 homes in the base's Tarawa Terrace neighborhood, disclosing the testing. A small portion of those homes may be affected, Fahy said. Ventilation systems could be installed if danger is found, he said.

Dole's notification requirement was in an amendment she offered Wednesday to a broad military money bill before the legislation was pulled from the floor in a showdown over Iraq. The larger bill may be back as soon as September.