The Portland Cement Building is an interesting one...I've seen if from the bridge approach many times. It's on the National Register of Historic Places. Portland Maps shows it as being owned by a company, "Pro Lab Northwest Inc," which has a Gresham address (at a house which sold just last summer, so that address might not be current). Anyway, I hope those people will be OK.
http://www.youtube.com/watch?v=983_qqatdTQ