I read this book about 18-Nov-2013. This is the first time I've read this book. The book is copyright 1995. This note was last modified Sunday, 12-Jan-2014 22:42:03 PST.
This note contains spoilers for the book.
Anna's back in the Southwest, guarding Anasazi sites. And "ill" is a great word for reading confusion in most fonts, particular when in title case as "Ill".
This time the problem is definitely from outside greed, in this case a construction company doing illegal hazardous waste disposal, of stuff so hazardous, and so incompetently, that it's triggering asthma attacks and other problems in park visitors miles away.
Let us not forget to mention Frederick the Fed. FBI agent, this is his second book, and he and Anna are showing signs of interest in each other. She's kind of solitary, and still dealing with (or putting off dealing with) the death of her husband quite a while ago now.