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Compliance 12 May 2026 · 4 min read

The landlord fallacy: who is actually liable for workplace radon?

The single most common compliance mistake among Helsinki SMEs is assuming the building owner handles radon. The law says otherwise.

By the Cazdon Labs team · physics-led indoor air science
Part of our Radon guide

Ask a restaurant owner who is responsible for radon and most will point at the landlord. It feels intuitive - the building is the owner’s. But Finnish law draws a sharp line between the building’s structure and the people working inside it.

Under the Radiation Act (859/2018, §155), the duty to ascertain occupational radon exposure rests with the employer operating the workspace - explicitly including tenants in rented premises. [7] The workplace reference level is 300 Bq/m³ as an annual average for regular work over 600 hours a year. [5]

What even counts as a workplace?

More than people expect. The obligation reaches any workspace that is wholly or partly underground, any ground-floor space on permeable soil or an esker, and any ground-floor space in a STUK-designated obligation area. [5] A basement prep kitchen, a street-level café, a back-office storeroom - all can be in scope.

Why this trips people up

Inspections routinely find deficiencies, and they cluster among small businesses in rented spaces precisely because of this misunderstanding. [7] The owner is responsible for the building’s structural integrity under separate health-protection rules - but that does not discharge the employer’s measurement and reporting duty.

What to do about it

Check whether your premises fall under the obligation, measure during the September–May season, and keep the documentation audit-ready. If a structural fix is ever needed, that’s the conversation to have with your landlord - but the measurement, and the liability for not doing it, sit with you.

References

  1. [5] Säteilyturvakeskus (STUK) - Radon at the workplace
  2. [7] Finnish Occupational Safety & Health Administration - Radon (Radiation Act 859/2018, §155)

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