Regarding Paradichlorobenzene (Para Moth)
I would purchase ONLY crystals specifically labelled for use on bee equipment. It may cost a little more but you are exposing yourself to risk of fines and lawsuits if you use any formulation that is not labeled for bees.
Furthermore, the label has the US EPA registration number and the instructions for disposal. It says right there that you can put materials that have been fumigated into a landfill. The EPA can't fine you if you follow their own instructions.
I used to use burning sulfur fumes to fumigate my honey house. This may be less toxic than pdb, but sulfur fumes can destroy metal in the building. I think using pdb crystals is the safest and most effective way that is currently approved.
The laws are meant to protect people and the environment. If you don't agree with them, try to get them changed -- but please don't take chances with chemicals. Even common chemicals can be hazardous, if used incorrectly.
Peter Borst
Ithaca, NY USA
http://www.people.cornell.edu/pages/plb6/