I have obtained several packaged bundles of Kiln-dried firewood. Several pieces of the split wood have mold growing on them, olive drab in color. Are these safe to use in my fireplace?

Here is a resource: Wood Mold (mould), woodsmoke, wood smoke contains active mold spores that are not killed in the fire. (http://www.burningissues.org/mold2005.htm)

It would seem you would be wise to not burn it.