It's hard to know. Are they just balls of cedar wood? Or are they a "cedar wood" type product to discourage moths and insects? I looked at the National Library of Medicine's Household Products Database to see what I could find. They list an item called "Enoz Cedar Pine Moth Balls," which contain a chemical called Naphlalene. You can read about it here: http://householdproducts.nlm.nih.gov/cgi-bin/household/brands?tbl=chem&id=25
Household Products Database (http://householdproducts.nlm.nih.gov/index.htm) may also have information about the specific name brand product you have. Good luck with your search!
at 11:27 AM on Jun. 20, 2011