For radon testing, you may want to consult the following sites: http://www.nrsb.org/nrsb-mem.htm http://www.aarst.com/ Regards, Bill Field bill-field@uiowa.edu ************************************************************************ The RADSAFE Frequently Asked Questions list, archives and subscription information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html