ATLANTA (AP) — Federal health officials say the lead poisoning rate for U.S. adults has fallen by more than half in the last 15 years, but it remains unusually high in Pennsylvania, Missouri and Kansas.

The Centers for Disease Control and Prevention on Thursday said that about 6 out of every 100,000 employed adults had lead poisoning in 2009, down from 14 per 100,000 in 1994.

Lead poisoning in adults is almost always due to at-work exposures. CDC officials say the decline may be tied to a reduction in the number of manufacturing jobs that involve lead, lead paint or lead dust.

The report focuses on adults who have elevated lead levels that are high enough to cause irritability and concentration problems as well as other symptoms.

(© Copyright 2011 The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten or redistributed.)