Stage 2: Measures to reduce radon concentrations in the workplace if the reference level is exceeded

Even if the annual averaged annual radon concentration at the workplace is below the reference level of 300 Becquerels per cubic metre, the BfS recommends examining whether voluntarily reducing the radon concentration is possible with reasonable effort.

Initiate, implement, and review measures

However, if the averaged annual radon concentration in the workplace exceeds 300 Becquerels per cubic metre, employers are obliged to take immediate action to reduce the radon concentration at the workplace. The same applies to voluntary measurements at indoor workplaces as it is a nationwide reference value.

The measures to reduce radon concentrations at affected workplaces must be implemented within 18 months of receiving the results. This is the only way to check the success of the measures taken within 30 months of the result of the first measurement by means of a new 12-month measurement (control measurement).

The control measurement must also be carried out with measuring devices from recognised providers. Employers are obliged to measure the radon concentration; they are also obliged to they are also obliged to inform workers and, if applicable, third parties about the results and to keep the report on the results of the measurement.

If measures are not feasible or are difficult to implement in time to meet the deadline for control measurement, the competent authority must be contacted. In exceptional cases, Stage 2 actions may be waived in agreement with the competent authority if there are special reasons for doing so (e.g. prevailing interests of occupational safety or health protection or the nature of the workplace). For example, a ventilation plan for an operating theatre would be contrary to the applicable hygiene regulations and the Infection Protection Act. The competent authority provides further information.

Further steps

If the radon concentration at the workplace cannot be reduced below 300 Becquerels per cubic metre, Stage 3 takes effect.

Stage 3: Registration of the workplace and estimation of radiation exposure if the reference level is continually exceeded

If the radon concentration at the workplace cannot be reduced below the reference level of 300 Becquerels per cubic metre, the workplace must be registered with the competent authority. The registration includes

• information on the type of workplace and the number of affected workers,
• the results of the measurements from Stage 1,
• information on the measures taken to reduce radon concentrations and the results of the control measurements from Stage 2,
• an outlook on which (additional) measures are planned to reduce the radiation exposure of the workers concerned by the inhalation of radon.

Within 6 months, employers must also estimate the expected exposure to radon (i.e. radon exposure) for the workers at this workplace. The result of the assessment has to be reported to the competent authority and kept for 5 years.

• If the estimate of the radon exposure shows that the expected effective dose at a workplace per calender year remains below 6 millisieverts, employers are obliged to minimise the exposure to radon at this workplace (taking all circumstances into account) and to review their assessment regularly. Measures to reduce exposure to radon can include restricting working hours in certain places or targeted ventilation.
  Employers must inform the competent authority if the registered workplace is abandoned. The same applies if they prove through a new measurement (as in stage 1) that the radon concentration is now below the reference value due to changes at the workplace.
  
• If the estimate of the radon exposure shows that the effective dose may exceed a value of 6 millisieverts per calender year, Stage 4 applies.

Stage 4: Requirements of occupational radiation protection take effect

If the estimate of the expected radon exposure at a workplace shows that the effective dose per calender year may exceed a value of 6 millisievert, requirements of occupational radiation protection must be met.

In addition to individual measures to reduce the radon exposure, these include the keeping of a radiation passport when working in external operating sites or medical supervision with regular examinations. The competent authority may, among others, also arrange for the establishment of radiation protection areas at the workplace.

The radiation dose of the workers concerned must also be determined continually in order to monitor the extent to which these workers are exposed to ionising radiation at the workplace. The dose meters for this purpose are provided by a measuring body appointed by the competent authority.

Employers are also obliged to register the affected workers in the Radiation Protection Register of the BfS. The Radiation Protection Register ensures that the limit values for the permissible annual radiation exposure and the occupational lifetime dose of all workers recorded in the register are complied with.

If the registered workplace is demonstrably changed in a way to make it impossible for the effective dose per calender year to exceed a value of 6 millisievert, employers have to report this fact to the competent authority.