Closed due to Agent orange?

What Jonathan said, and they are cleaning up areas and expanding/opening new trails. There are big plans for the future as well, connecting several smaller trails into one large system, ostensibly from Marina (or farther north) to Monterey (or farther south).

I've not heard of any Agent Orange. Parts of the base are permanently closed/off-limits due to munitions danger. But that's publicly stated on the map you can get.