A federal report obtained by The Associated Press shows that the Legionnaire's disease outbreak that killed 12 residents of the Illinois Veterans Home in Quincy this summer and sickened dozens was likely spread by an aging water system at a 129-year-old facility that lacked several safeguards.

The Centers for Disease Control report was released to the AP through a public records request.

CDC environmental health specialists cited an "extensive and poorly understood water distribution system" and a "general lack of understanding of water system details" at the home.

The state already is pursuing a $4.8 million project to replace the home's water system and make other emergency repairs at Illinois' oldest and largest home for veterans and their spouses.