Pennsylvania radon directory comparison
Source reports: September 1, 2026. Retrieved and analyzed: September 14, 2026.
Analysis: RadonTestingCompanies.com
Article: https://radontestingcompanies.com/guides/pennsylvania-radon-directory-study

SCOPE
The four official Pennsylvania DEP reports are compared separately. Counts are
source entries with a printed PA state and a reported Pennsylvania county.
Entries mix firms, individuals, and employees; they are not counts of unique
people or companies. A listed county is not a service area. A zero does not
establish an absence of available service, a shortage, or a household radon risk.
No claim of a complete statewide or national workforce is made.

COLUMN DEFINITIONS: county-comparison.csv
county_fips: Five-character Census county identifier (Pennsylvania begins 42).
county: Pennsylvania county name.
testing_county: Entries in CountyTest.pdf with a PA address in this county.
testing_alphabetical: Entries in WebTestAlpha.pdf with a PA address in this county.
mitigation_county: Entries in CountyMitigation.pdf with a PA address in this county.
mitigation_alphabetical: Entries in WebMitigationAlpha.pdf with a PA address in this county.
same_presence_in_both_versions: True when both testing presence and mitigation
presence agree across versions; it does not mean entry counts agree.

All 67 counties are included. Source issue dates are September 1, 2026 throughout.
Research dates are separate from individual credential verification dates.

METHOD
Two extractions (PDF.js and Poppler) agreed on ID, state, and county for all 610
testing and 239 mitigation rows in the county-sorted reports. The alphabetical
reports were then compared using Poppler. IDs were unique within each report.
Other-state addresses were excluded from Pennsylvania county counts.
The reported county was retained rather than re-geocoding the address.
Testing ID 3501's alphabetical county label NORTHUMBERLAN was normalized to
NORTHUMBERLAND using the full county attached to the same ID and PA state in
CountyTest.pdf. No other Pennsylvania county normalization was needed.
All county totals reconcile to their corresponding report totals.

PA-address totals: county testing 501; alphabetical testing 542;
county mitigation 194; alphabetical mitigation 114.
Both versions produce the same presence groups: 35 counties with both services,
19 testing only, 13 neither, and zero mitigation only.
The alphabetical testing report has 46 additional IDs across all addresses.
The county mitigation report has 102 additional IDs, all in the 7000 series,
which DEP describes as mitigation firm employees. The full reason for the
different report populations has not been established. Reports were not combined
into a supposedly complete roster. Agreement does not establish completeness.

SOURCES AND REPRODUCTION
The accompanying source-manifest.json contains exact URLs, retrieval timestamps,
byte sizes, and SHA-256 hashes of the four original PDFs. Use those dated files
to reproduce the analysis. A hash change means a different source artifact.
Official directory:
https://www.pa.gov/agencies/dep/programs-and-services/radiation-protection/radon-division/radon-services-directory
Census county reference:
https://www.census.gov/geographies/reference-files/time-series/geo/gazetteer-files.2025.html
Research code and records:
https://github.com/Thestral12/radon/tree/99596823cd3638ea7a1b9dac587008eb8d635a03/docs/research/radon-credential-locations-2026-09-14

DEP has not reviewed or endorsed this analysis. No external professional review
is claimed. Historical research counts may differ from separately refreshed
directory listings. Source material is attributed without claiming an open-data
license for the original PDFs. This aggregate download contains no names,
addresses, email addresses, or phone numbers.