Regular showers could pose a health risk and even result in brain damage, according to U.S. researchers.

Dr. John Spangler of Wake Forest University School of Medicine in Winston-Salem, N.C., says breathing in small amounts of manganese dissolved in the water may harm the nervous system -- even at levels normally considered safe, reported Sky News Sunday.

Although manganese levels in public water supplies are monitored, government regulators have not considered the long-term effects of inhaling vaporized manganese while showering, Spangler said.

"Nearly 9 million people in the United States are exposed to manganese levels that our study shows may cause toxic effects," the researcher said. "Inhaling manganese, rather than eating or drinking it, is far more efficient at delivering manganese to the brain."

Copyright 2005 by United Press International