TY - BOOK CN - EP 4.2: CY - [Washington, D.C.?] : DA - [1993] ID - 237997 KW - Radon KW - Radioactive pollution of soils KW - Indoor air pollution N1 - "This document was prepared ... in conjunction with the U.S. Geological Survey (USGS)"--1st prelim. p. N1 - Distributed to depository libraries in microfiche. N1 - Shipping list no.: 98-0371-M. N1 - "September, 1993." N1 - "402-R-93-052"--Cover. PB - Radon Division, Office of Radiation and Indoor Air, U.S. Environmental Protection Agency, PP - [Washington, D.C.?] : PY - [1993] T1 - EPA's map of radon zones. TI - EPA's map of radon zones. ER -