(AP) – University of Missouri Libraries officials are trying to decide what to do with about 600,000 books damaged by mold at an off-campus storage site.

Libraries Director Jim Cogswell says the volumes were stored at Subtera, an underground storage site in north Columbia. The damage was discovered last October.

The Columbia Daily Tribune reports (http://bit.ly/1jILYhw ) a health and safety officer said last week that the mold involved didn’t endanger public health.

Cogswell says it’s likely fewer than half the books will be saved because it would cost $3 per volume to remove the mold – a tab of about $1.8 million.

He says the goal is to save books published before 1870.