University of La Laguna Closes 65 Rooms Over High Radon Levels

The University of La Laguna (ULL) has closed 65 rooms after discovering radon gas levels that exceed legal safety limits for workplaces. The decision follows the largest radon testing campaign ever conducted in the Canary Islands.

Radon is a naturally occurring radioactive gas that rises from the ground. The World Health Organization identifies it as the second leading cause of lung cancer after smoking. In Spain, the legal limit for enclosed spaces is 300 becquerels per cubic meter. When levels exceed this, institutions are required to take immediate action to protect students and staff.

The university’s study began last October, with 1,454 sensors placed across campus for three months to ensure accurate annual readings. So far, 921 results have been processed. In addition to the 65 rooms that exceeded 500 becquerels, another 62 rooms showed intermediate levels between 300 and 500 becquerels.

To address the issue, the university is prioritizing natural ventilation and ongoing monitoring to bring gas levels down before these spaces reopen. The impact varies by location: the Anchieta campus—home to the Biology, Pharmacy, Chemistry, and Engineering faculties—is the most affected. In contrast, the Guajara campus is largely unaffected, and issues at the Central Building and the Faculty of Education are considered minor and easily fixed with better airflow.

Most of the university’s facilities—794 areas in total—remain within safe limits. By acting now, at the end of the academic year, the university aims to resolve the air quality concerns while minimizing disruption to students and staff.