National Radon Zones - City-Data (more interactive than USEPA)

Alabama Zip Codes by Zip Code - WIth detail records by county and zip codes

Califormia Radon Levels Sorted by ZIp Codes - Database of 48,278 radon tests

Delaware Radon Levels by Zip Code - Data collected from 1993 to 2011

Florida Radon Levels - Searchable by zip code

Florida Residential Building Radon Protection Map - Detailed construction info

Ohio Radon Levels by Zip Code - 227,407 data points for 1494 zip codes

Oregon Radon Test Results by Zip Code - Long term and short term results by zip

Nevada Radon Test Results by Zip Code - Various years as well

Pennsylvania Radon Test Results by Zip Code - Searchable by zip code

South Carolina Radon Test Results by Zip Code - PDF provided by SCDHEC

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