Citation standards

The approved sources

We cite EPA for radon background, the 4 pCi/L action level and the 2–4 consideration band, testing guidance and protocol, mitigation methods and system behaviour, real-estate testing practice, health risk framing, and the meaning of radon zone designations. Each EPA publication in our registry has a recorded scope — the specific class of claim it is permitted to support — and is not used outside it.

We cite state agencies for state programmes, state licensing and certification, and state testing guidance. We cite state statutes for what those statutes require, which is how disclosure obligations are sourced.

Each state resource centre names the agency that answers questions about that state, so a reader can go to the primary source directly rather than trusting our summary of it.

What we refuse as a source

Competitor content. Another mitigation company’s page is marketing, whatever it asserts, and citing it would launder a sales claim into an apparent fact.

Aggregator sites, content farms, and unattributed industry statistics. If a figure cannot be traced to the body that produced it, we do not publish the figure.

Our own pages, as authority for a factual claim. Internal links are navigation, not evidence, and we do not present them as sourcing.

How compliance is enforced

The approved sources live in a single registry in the codebase. Every citation rendered anywhere on the site comes from that registry, and the pre-deployment quality suite scans the built HTML and fails if any citation points at a host outside the approved list.

Two further checks run alongside it. Every source in the registry must be used by at least one page, so a citation cannot sit there as decoration. And pages making particular classes of claim — real-estate, action-level, mitigation-method, health-risk — must cite a source whose recorded scope actually covers that class.

That last check is the one that catches the common failure: a page carrying three general radon citations while making a specific transaction claim none of them supports.

A limitation we will state plainly

Citation URLs on this site are recorded in their canonical published forms and are not re-fetched during the build, because this build environment has no outbound network access beyond package and source repositories.

That means a link could in principle go stale between our recording it and your clicking it. The registry carries a note describing this and the command to verify every URL from an unrestricted machine. We would rather tell you that than imply a live check we are not performing.

Adding a source

A new source is added only when it is authoritative for a claim we need to make and no existing source covers it. Adding one requires recording what it is permitted to support, which forces the question of whether it is really needed.

Additions are logged in the revision history of this page, so the standard itself has a change record.