The substance in question is chlorine trifluoride, which is in a gas cylinder. The substance had been previously used for the analysis of rock samples. ETH Zurich has requested support from the Zurich Cantonal Police and other specialist institutions in planning and carrying out the disposal.
Precautionary measures on 7 June 2026
The gas cylinder is being stored in a laboratory accessible only to authorised personnel. According to the assessment of external experts, there is no acute danger. However, increased safety requirements will apply during its loading and transport. The Zurich Cantonal Police has therefore laid down various precautionary safety measures to ensure this is carried out in a controlled and safe manner:
The following ETH buildings will remain closed and cannot be accessed on this day: CLA, CLD, CLT, EKZ, LEE, LEO, ML, ML-FHK, MLY, NO (including Focus Terra), NW and TAN.
The parking garages in ML and HG will not be accessible on this day.
The following residential buildings, which ETH rents out to students and visiting lecturers, must be temporarily vacated from 10:00 to 16:30: CLX, CLE, CLF, CLG, SOQ, SOR, SOK, SOP, SON.
The ETH Main Building will remain accessible via the main entrance and the Polyterrasse; the side entrances will remain closed.
There will be temporary evacuations as well as traffic and public transport restrictions in the immediate vicinity of the buildings in question. The Polybahn will continue to operate. Residents affected by these measures have been directly informed by the Zurich Cantonal Police.
According to current plans, the ETH buildings affected will be accessible again as usual starting Monday, 8 June 2026.
ETH Zurich would like to apologise for the restrictions imposed on staff, students, residents and other affected parties due to the safety measures. We would like to sincerely thank the emergency services and specialist agencies for their professional support in planning and carrying out the work.