[
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Alabama",
    "state_abbreviation": "AL",
    "epa_source_rows": 67,
    "zone_1_rows": 13,
    "zone_1_share_percent": 19.4,
    "zone_2_rows": 33,
    "zone_2_share_percent": 49.25,
    "zone_3_rows": 21,
    "zone_3_share_percent": 31.34,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 67,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Alaska",
    "state_abbreviation": "AK",
    "epa_source_rows": 27,
    "zone_1_rows": 0,
    "zone_1_share_percent": 0.0,
    "zone_2_rows": 6,
    "zone_2_share_percent": 22.22,
    "zone_3_rows": 21,
    "zone_3_share_percent": 77.78,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 23,
    "legacy_or_unmatched_source_rows": 4,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Arizona",
    "state_abbreviation": "AZ",
    "epa_source_rows": 15,
    "zone_1_rows": 0,
    "zone_1_share_percent": 0.0,
    "zone_2_rows": 15,
    "zone_2_share_percent": 100.0,
    "zone_3_rows": 0,
    "zone_3_share_percent": 0.0,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 15,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Arkansas",
    "state_abbreviation": "AR",
    "epa_source_rows": 75,
    "zone_1_rows": 0,
    "zone_1_share_percent": 0.0,
    "zone_2_rows": 14,
    "zone_2_share_percent": 18.67,
    "zone_3_rows": 61,
    "zone_3_share_percent": 81.33,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 75,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "California",
    "state_abbreviation": "CA",
    "epa_source_rows": 58,
    "zone_1_rows": 2,
    "zone_1_share_percent": 3.45,
    "zone_2_rows": 29,
    "zone_2_share_percent": 50.0,
    "zone_3_rows": 27,
    "zone_3_share_percent": 46.55,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 58,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Colorado",
    "state_abbreviation": "CO",
    "epa_source_rows": 64,
    "zone_1_rows": 52,
    "zone_1_share_percent": 81.25,
    "zone_2_rows": 12,
    "zone_2_share_percent": 18.75,
    "zone_3_rows": 0,
    "zone_3_share_percent": 0.0,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": true,
    "matched_to_2025_census_rows": 64,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Connecticut",
    "state_abbreviation": "CT",
    "epa_source_rows": 8,
    "zone_1_rows": 4,
    "zone_1_share_percent": 50.0,
    "zone_2_rows": 3,
    "zone_2_share_percent": 37.5,
    "zone_3_rows": 1,
    "zone_3_share_percent": 12.5,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 0,
    "legacy_or_unmatched_source_rows": 8,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Delaware",
    "state_abbreviation": "DE",
    "epa_source_rows": 3,
    "zone_1_rows": 0,
    "zone_1_share_percent": 0.0,
    "zone_2_rows": 1,
    "zone_2_share_percent": 33.33,
    "zone_3_rows": 2,
    "zone_3_share_percent": 66.67,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 3,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "District of Columbia",
    "state_abbreviation": "DC",
    "epa_source_rows": 1,
    "zone_1_rows": 0,
    "zone_1_share_percent": 0.0,
    "zone_2_rows": 0,
    "zone_2_share_percent": 0.0,
    "zone_3_rows": 1,
    "zone_3_share_percent": 100.0,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 1,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Florida",
    "state_abbreviation": "FL",
    "epa_source_rows": 67,
    "zone_1_rows": 0,
    "zone_1_share_percent": 0.0,
    "zone_2_rows": 9,
    "zone_2_share_percent": 13.43,
    "zone_3_rows": 58,
    "zone_3_share_percent": 86.57,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 67,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Georgia",
    "state_abbreviation": "GA",
    "epa_source_rows": 159,
    "zone_1_rows": 4,
    "zone_1_share_percent": 2.52,
    "zone_2_rows": 55,
    "zone_2_share_percent": 34.59,
    "zone_3_rows": 100,
    "zone_3_share_percent": 62.89,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 159,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Hawaii",
    "state_abbreviation": "HI",
    "epa_source_rows": 5,
    "zone_1_rows": 0,
    "zone_1_share_percent": 0.0,
    "zone_2_rows": 0,
    "zone_2_share_percent": 0.0,
    "zone_3_rows": 5,
    "zone_3_share_percent": 100.0,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 5,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Idaho",
    "state_abbreviation": "ID",
    "epa_source_rows": 44,
    "zone_1_rows": 19,
    "zone_1_share_percent": 43.18,
    "zone_2_rows": 20,
    "zone_2_share_percent": 45.45,
    "zone_3_rows": 5,
    "zone_3_share_percent": 11.36,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 44,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Illinois",
    "state_abbreviation": "IL",
    "epa_source_rows": 102,
    "zone_1_rows": 56,
    "zone_1_share_percent": 54.9,
    "zone_2_rows": 43,
    "zone_2_share_percent": 42.16,
    "zone_3_rows": 3,
    "zone_3_share_percent": 2.94,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": true,
    "matched_to_2025_census_rows": 102,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Indiana",
    "state_abbreviation": "IN",
    "epa_source_rows": 92,
    "zone_1_rows": 57,
    "zone_1_share_percent": 61.96,
    "zone_2_rows": 35,
    "zone_2_share_percent": 38.04,
    "zone_3_rows": 0,
    "zone_3_share_percent": 0.0,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": true,
    "matched_to_2025_census_rows": 92,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Iowa",
    "state_abbreviation": "IA",
    "epa_source_rows": 99,
    "zone_1_rows": 99,
    "zone_1_share_percent": 100.0,
    "zone_2_rows": 0,
    "zone_2_share_percent": 0.0,
    "zone_3_rows": 0,
    "zone_3_share_percent": 0.0,
    "all_epa_source_rows_zone_1": true,
    "majority_epa_source_rows_zone_1": true,
    "matched_to_2025_census_rows": 99,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Kansas",
    "state_abbreviation": "KS",
    "epa_source_rows": 105,
    "zone_1_rows": 65,
    "zone_1_share_percent": 61.9,
    "zone_2_rows": 40,
    "zone_2_share_percent": 38.1,
    "zone_3_rows": 0,
    "zone_3_share_percent": 0.0,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": true,
    "matched_to_2025_census_rows": 105,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Kentucky",
    "state_abbreviation": "KY",
    "epa_source_rows": 120,
    "zone_1_rows": 30,
    "zone_1_share_percent": 25.0,
    "zone_2_rows": 82,
    "zone_2_share_percent": 68.33,
    "zone_3_rows": 8,
    "zone_3_share_percent": 6.67,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 120,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Louisiana",
    "state_abbreviation": "LA",
    "epa_source_rows": 64,
    "zone_1_rows": 0,
    "zone_1_share_percent": 0.0,
    "zone_2_rows": 0,
    "zone_2_share_percent": 0.0,
    "zone_3_rows": 64,
    "zone_3_share_percent": 100.0,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 64,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Maine",
    "state_abbreviation": "ME",
    "epa_source_rows": 16,
    "zone_1_rows": 12,
    "zone_1_share_percent": 75.0,
    "zone_2_rows": 4,
    "zone_2_share_percent": 25.0,
    "zone_3_rows": 0,
    "zone_3_share_percent": 0.0,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": true,
    "matched_to_2025_census_rows": 16,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Maryland",
    "state_abbreviation": "MD",
    "epa_source_rows": 24,
    "zone_1_rows": 8,
    "zone_1_share_percent": 33.33,
    "zone_2_rows": 8,
    "zone_2_share_percent": 33.33,
    "zone_3_rows": 8,
    "zone_3_share_percent": 33.33,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 24,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Massachusetts",
    "state_abbreviation": "MA",
    "epa_source_rows": 14,
    "zone_1_rows": 3,
    "zone_1_share_percent": 21.43,
    "zone_2_rows": 10,
    "zone_2_share_percent": 71.43,
    "zone_3_rows": 1,
    "zone_3_share_percent": 7.14,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 14,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Michigan",
    "state_abbreviation": "MI",
    "epa_source_rows": 83,
    "zone_1_rows": 9,
    "zone_1_share_percent": 10.84,
    "zone_2_rows": 32,
    "zone_2_share_percent": 38.55,
    "zone_3_rows": 42,
    "zone_3_share_percent": 50.6,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 83,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Minnesota",
    "state_abbreviation": "MN",
    "epa_source_rows": 87,
    "zone_1_rows": 68,
    "zone_1_share_percent": 78.16,
    "zone_2_rows": 19,
    "zone_2_share_percent": 21.84,
    "zone_3_rows": 0,
    "zone_3_share_percent": 0.0,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": true,
    "matched_to_2025_census_rows": 87,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Mississippi",
    "state_abbreviation": "MS",
    "epa_source_rows": 82,
    "zone_1_rows": 0,
    "zone_1_share_percent": 0.0,
    "zone_2_rows": 8,
    "zone_2_share_percent": 9.76,
    "zone_3_rows": 74,
    "zone_3_share_percent": 90.24,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 82,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Missouri",
    "state_abbreviation": "MO",
    "epa_source_rows": 115,
    "zone_1_rows": 11,
    "zone_1_share_percent": 9.57,
    "zone_2_rows": 97,
    "zone_2_share_percent": 84.35,
    "zone_3_rows": 7,
    "zone_3_share_percent": 6.09,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 115,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Montana",
    "state_abbreviation": "MT",
    "epa_source_rows": 57,
    "zone_1_rows": 50,
    "zone_1_share_percent": 87.72,
    "zone_2_rows": 7,
    "zone_2_share_percent": 12.28,
    "zone_3_rows": 0,
    "zone_3_share_percent": 0.0,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": true,
    "matched_to_2025_census_rows": 56,
    "legacy_or_unmatched_source_rows": 1,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Nebraska",
    "state_abbreviation": "NE",
    "epa_source_rows": 93,
    "zone_1_rows": 53,
    "zone_1_share_percent": 56.99,
    "zone_2_rows": 24,
    "zone_2_share_percent": 25.81,
    "zone_3_rows": 16,
    "zone_3_share_percent": 17.2,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": true,
    "matched_to_2025_census_rows": 93,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Nevada",
    "state_abbreviation": "NV",
    "epa_source_rows": 17,
    "zone_1_rows": 9,
    "zone_1_share_percent": 52.94,
    "zone_2_rows": 7,
    "zone_2_share_percent": 41.18,
    "zone_3_rows": 1,
    "zone_3_share_percent": 5.88,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": true,
    "matched_to_2025_census_rows": 17,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "New Hampshire",
    "state_abbreviation": "NH",
    "epa_source_rows": 10,
    "zone_1_rows": 1,
    "zone_1_share_percent": 10.0,
    "zone_2_rows": 9,
    "zone_2_share_percent": 90.0,
    "zone_3_rows": 0,
    "zone_3_share_percent": 0.0,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 10,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "New Jersey",
    "state_abbreviation": "NJ",
    "epa_source_rows": 21,
    "zone_1_rows": 7,
    "zone_1_share_percent": 33.33,
    "zone_2_rows": 11,
    "zone_2_share_percent": 52.38,
    "zone_3_rows": 3,
    "zone_3_share_percent": 14.29,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 21,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "New Mexico",
    "state_abbreviation": "NM",
    "epa_source_rows": 33,
    "zone_1_rows": 7,
    "zone_1_share_percent": 21.21,
    "zone_2_rows": 26,
    "zone_2_share_percent": 78.79,
    "zone_3_rows": 0,
    "zone_3_share_percent": 0.0,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 33,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "New York",
    "state_abbreviation": "NY",
    "epa_source_rows": 62,
    "zone_1_rows": 34,
    "zone_1_share_percent": 54.84,
    "zone_2_rows": 13,
    "zone_2_share_percent": 20.97,
    "zone_3_rows": 15,
    "zone_3_share_percent": 24.19,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": true,
    "matched_to_2025_census_rows": 62,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "North Carolina",
    "state_abbreviation": "NC",
    "epa_source_rows": 100,
    "zone_1_rows": 8,
    "zone_1_share_percent": 8.0,
    "zone_2_rows": 31,
    "zone_2_share_percent": 31.0,
    "zone_3_rows": 61,
    "zone_3_share_percent": 61.0,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 100,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "North Dakota",
    "state_abbreviation": "ND",
    "epa_source_rows": 53,
    "zone_1_rows": 53,
    "zone_1_share_percent": 100.0,
    "zone_2_rows": 0,
    "zone_2_share_percent": 0.0,
    "zone_3_rows": 0,
    "zone_3_share_percent": 0.0,
    "all_epa_source_rows_zone_1": true,
    "majority_epa_source_rows_zone_1": true,
    "matched_to_2025_census_rows": 53,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Ohio",
    "state_abbreviation": "OH",
    "epa_source_rows": 88,
    "zone_1_rows": 53,
    "zone_1_share_percent": 60.23,
    "zone_2_rows": 35,
    "zone_2_share_percent": 39.77,
    "zone_3_rows": 0,
    "zone_3_share_percent": 0.0,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": true,
    "matched_to_2025_census_rows": 88,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Oklahoma",
    "state_abbreviation": "OK",
    "epa_source_rows": 77,
    "zone_1_rows": 0,
    "zone_1_share_percent": 0.0,
    "zone_2_rows": 9,
    "zone_2_share_percent": 11.69,
    "zone_3_rows": 68,
    "zone_3_share_percent": 88.31,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 77,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Oregon",
    "state_abbreviation": "OR",
    "epa_source_rows": 36,
    "zone_1_rows": 0,
    "zone_1_share_percent": 0.0,
    "zone_2_rows": 21,
    "zone_2_share_percent": 58.33,
    "zone_3_rows": 15,
    "zone_3_share_percent": 41.67,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 36,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Pennsylvania",
    "state_abbreviation": "PA",
    "epa_source_rows": 67,
    "zone_1_rows": 49,
    "zone_1_share_percent": 73.13,
    "zone_2_rows": 17,
    "zone_2_share_percent": 25.37,
    "zone_3_rows": 1,
    "zone_3_share_percent": 1.49,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": true,
    "matched_to_2025_census_rows": 67,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Rhode Island",
    "state_abbreviation": "RI",
    "epa_source_rows": 5,
    "zone_1_rows": 2,
    "zone_1_share_percent": 40.0,
    "zone_2_rows": 2,
    "zone_2_share_percent": 40.0,
    "zone_3_rows": 1,
    "zone_3_share_percent": 20.0,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 5,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "South Carolina",
    "state_abbreviation": "SC",
    "epa_source_rows": 46,
    "zone_1_rows": 1,
    "zone_1_share_percent": 2.17,
    "zone_2_rows": 8,
    "zone_2_share_percent": 17.39,
    "zone_3_rows": 37,
    "zone_3_share_percent": 80.43,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 46,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "South Dakota",
    "state_abbreviation": "SD",
    "epa_source_rows": 66,
    "zone_1_rows": 48,
    "zone_1_share_percent": 72.73,
    "zone_2_rows": 18,
    "zone_2_share_percent": 27.27,
    "zone_3_rows": 0,
    "zone_3_share_percent": 0.0,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": true,
    "matched_to_2025_census_rows": 65,
    "legacy_or_unmatched_source_rows": 1,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Tennessee",
    "state_abbreviation": "TN",
    "epa_source_rows": 95,
    "zone_1_rows": 38,
    "zone_1_share_percent": 40.0,
    "zone_2_rows": 32,
    "zone_2_share_percent": 33.68,
    "zone_3_rows": 25,
    "zone_3_share_percent": 26.32,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 95,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Texas",
    "state_abbreviation": "TX",
    "epa_source_rows": 254,
    "zone_1_rows": 0,
    "zone_1_share_percent": 0.0,
    "zone_2_rows": 39,
    "zone_2_share_percent": 15.35,
    "zone_3_rows": 215,
    "zone_3_share_percent": 84.65,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 254,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Utah",
    "state_abbreviation": "UT",
    "epa_source_rows": 29,
    "zone_1_rows": 7,
    "zone_1_share_percent": 24.14,
    "zone_2_rows": 22,
    "zone_2_share_percent": 75.86,
    "zone_3_rows": 0,
    "zone_3_share_percent": 0.0,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 29,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Vermont",
    "state_abbreviation": "VT",
    "epa_source_rows": 14,
    "zone_1_rows": 0,
    "zone_1_share_percent": 0.0,
    "zone_2_rows": 12,
    "zone_2_share_percent": 85.71,
    "zone_3_rows": 2,
    "zone_3_share_percent": 14.29,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 14,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Virginia",
    "state_abbreviation": "VA",
    "epa_source_rows": 136,
    "zone_1_rows": 64,
    "zone_1_share_percent": 47.06,
    "zone_2_rows": 28,
    "zone_2_share_percent": 20.59,
    "zone_3_rows": 44,
    "zone_3_share_percent": 32.35,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 133,
    "legacy_or_unmatched_source_rows": 3,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Washington",
    "state_abbreviation": "WA",
    "epa_source_rows": 39,
    "zone_1_rows": 7,
    "zone_1_share_percent": 17.95,
    "zone_2_rows": 14,
    "zone_2_share_percent": 35.9,
    "zone_3_rows": 18,
    "zone_3_share_percent": 46.15,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 39,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "West Virginia",
    "state_abbreviation": "WV",
    "epa_source_rows": 55,
    "zone_1_rows": 20,
    "zone_1_share_percent": 36.36,
    "zone_2_rows": 29,
    "zone_2_share_percent": 52.73,
    "zone_3_rows": 6,
    "zone_3_share_percent": 10.91,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 55,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Wisconsin",
    "state_abbreviation": "WI",
    "epa_source_rows": 72,
    "zone_1_rows": 28,
    "zone_1_share_percent": 38.89,
    "zone_2_rows": 44,
    "zone_2_share_percent": 61.11,
    "zone_3_rows": 0,
    "zone_3_share_percent": 0.0,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": false,
    "matched_to_2025_census_rows": 72,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  },
  {
    "dataset_version": "2026-07-24.1",
    "state_name": "Wyoming",
    "state_abbreviation": "WY",
    "epa_source_rows": 23,
    "zone_1_rows": 21,
    "zone_1_share_percent": 91.3,
    "zone_2_rows": 2,
    "zone_2_share_percent": 8.7,
    "zone_3_rows": 0,
    "zone_3_share_percent": 0.0,
    "all_epa_source_rows_zone_1": false,
    "majority_epa_source_rows_zone_1": true,
    "matched_to_2025_census_rows": 23,
    "legacy_or_unmatched_source_rows": 0,
    "underlying_map_model_year": 1993,
    "source_file_vintage": "September 2025",
    "verification_date": "2026-07-24",
    "verification_tier": "★",
    "source_url": "https://www.epa.gov/radon/epa-map-radon-zones-0",
    "denominator_note": "Counts refer to rows in the EPA September 2025 source file. They are not counts of homes or radon tests, and source geography may differ from current Census county equivalents."
  }
]